TECH-X-FLEX Hand-Held Tester User Manual Manual_Tech_X_Flex_Base_Issue1 Spirent Communications

Spirent Communications Hand-Held Tester

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Tech-X Flex™
Base Unit User Guide
Spirent Communications
20324 Seneca Meadows Parkway
Germantown, MD 20876 USA
+1 301.444.2400
800.385.0110 (USA only)
www.spirent.com
Tech-X Flex™
Base Unit User Guide Issue 1
Contents
1: Introduction
1.1 Documentation notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1.1 Document purpose and scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1.2 Definitions of terms and acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1.3 Additional documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2 Product introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2.1 Product purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2.2 User prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.2.3 Base unit features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.2.4 Front panel controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.2.5 LED indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1.2.6 Base unit physical interfaces (ports) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
1.3 General product handling and operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
1.3.1 Powering on/off and sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
1.3.2 Attaching, detaching, and handling modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
1.3.3 Attaching the Wi-Fi antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
1.3.4 Attaching the strap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
1.3.5 About the touchscreen display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
1.3.6 Selecting the active interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
1.3.7 Starting a function or test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
1.3.8 Stopping a test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
1.3.9 Saving results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
1.3.10 Interpreting results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
1.4 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
1.4.1 Battery replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
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Base Unit User Guide Issue 1
Tech-X Flex™
1.5 Technical support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
2: Wi-Fi Testing Menu
Intro
2.1 Functionality note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2 Wi-Fi overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Wi-Fi
2.2.1 Wi-Fi support details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
2.2.2 Wi-Fi testing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
2.2.3 If you cannot connect (troubleshooting tips) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-3
2.2.4 About the connection history and “auto-connect” networks . . . . . . . . . . . . . . . . . . . .2-4
2.3 Wi-Fi Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
10/100
2.3.1 Wi-Fi Setup > Scan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
Setup - Scan (Wi-Fi Setup) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6
Results - Scan (Wi-Fi Setup) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6
2.3.2 Wi-Fi Setup > Connect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6
Setup - Connect (Wi-Fi Setup) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-7
Results - Connect (Wi-Fi Setup) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9
2.3.3 Wi-Fi Setup > Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-9
2.3.4 Wi-Fi Setup > View Auto-Connect Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10
System
2.4 IP Network Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
2.5 Ping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
IP/Video
2.6 Traceroute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
2.7 Web Browser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
3: 10/100 Testing Menu
3.1 Functionality note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Specs
3.2 About the 10/100 ports and connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3.3 10/100 testing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3.4 IP Network Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3.5 Ping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3.6 Traceroute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3.7 Web Browser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3.8 IP Video Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
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Tech-X Flex™
Base Unit User Guide Issue 1
3.9 Passive testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Intro
3.9.1 Unit setup for passive testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.9.2 Passive Video Quality of Service (QoS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
4: System Menu
4.1 Record Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Wi-Fi
4.2 10/100 Admin Port. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
4.3 Set Date and Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
4.4 Auto Sleep Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
4.5 Version Info . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
10/100
4.6 Battery Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
4.7 Channel Guide/Network Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4.7.1 About channel guides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
4.7.2 Importing channel guides to the unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
System
4.8 Download Channel Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
4.9 Wireless ON/OFF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
4.10 Calibrate Touchscreen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
4.11 Licensed Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
IP/Video
4.12 Update Firmware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
5: IP and Video Testing
5.1 IP Network Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Specs
5.1.1 Setup - IP Network Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
5.1.2 Results - IP Network Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.2 Connection Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.3 Ping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
5.3.1 Setup - Ping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
5.3.2 Results - Ping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
5.4 Traceroute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
5.4.1 Setup - Traceroute test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
5.4.2 Results - Traceroute test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
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5.5 Web Browser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
5.5.1 Setup - Web Browser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-7
Intro
5.6 IP Video testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Wi-Fi
5.6.1 Video Quality of Service (QoS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-8
Setup - Video Quality of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-8
Results - Video Quality of Service (VQM test) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-14
Digital video concepts overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-20
About basic video and audio compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
About MPEG transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23
About IP multicast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-25
Quality measurement overview and additional results descriptions . . . . . . . . . . . . . . .5-27
How the analysis works - An overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27
About MOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28
About gap and burst states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29
Other test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29
Additional video testing notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-30
About the IP address specified for testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30
About encrypted (scrambled) signals and frame type recognition . . . . . . . . . . . . . 5-30
5.6.2 Channel Change Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-30
Setup - Channel Change Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-31
Results - Channel Change Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-32
How channel change time is calculated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-32
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System
IP/Video
6: Specifications
6.1 General specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
6.2 Wi-Fi specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Specs
6.3 FCC compliance statements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
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1: Introduction
This section provides an overview of the Tech-X Flex product and includes the following information:
•
Documentation notes on page 1-1 - Describes this document and the terminology within.
•
Product introduction on page 1-2 - Describes the physical unit and includes a high-level overview of
system features and capabilities.
•
General product handling and operation on page 1-9 - Describes basic procedures for handling and
operating the unit.
•
Maintenance on page 1-15 - Describes maintenance requirements and procedures for the unit.
•
Technical support on page 1-17 - Provides contact information.
1.1 Documentation notes
1.1.1 Document purpose and scope
This document is intended for field technicians and other personnel who use the product for circuit and
network testing. Depending upon your licensing agreement, your unit may not include all the
functionality presented in this document. For more information about licensing arrangements, please
contact a Spirent account manager.
1.1.2 Definitions of terms and acronyms
For clarity, the following terms are defined:
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Tech-X Flex™
Unit - A Tech-X Flex device in general, with or without a module attached, as applicable to the
respective context.
•
Base Unit - The core handheld component to which modules attach. The base unit has an
independent suite of functionality which is described in this document. The use of modules does not
change base unit functionality.
•
Module - A modular hardware component designed to attach and interface with the Tech-X Flex base
unit that provides additional functionality. Documentation for modules is provided separately from this
document.
•
Provider - A broadband service provider, such as a telephone or cable company.
•
Subscriber - A customer receiving broadband services from a provider.
Intro
•
Wi-Fi
Additionally, note the following common acronyms:
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System
•
FTTH/FTTP - Fiber To The Home/Fiber To The Premises
•
IP - Internet Protocol
•
IPTV - IP Television
•
LAN - Local Area Network
•
MoCA® - Multimedia over Coax Alliance
•
STB - Set-Top Box
•
WAN - Wide Area Network
1.1.3 Additional documentation
IP/Video
Additional documentation (including an electronic version of this document) can be found on Spirent’s
Customer Service Network. Support requests and training information are also available on the site. Use
the URL below to register and gain access:
http://assure.spirentcom.com/extranet/
Specs
1.2 Product introduction
The following sections provide a high-level overview of the unit.
1.2.1 Product purpose
The unit is designed to assist with the setup and troubleshooting of home networks, especially as related
to broadband services delivered by high-speed DSL, cable, and fiber-to-the-premises (FTTP)
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Wi-Fi
Primarily, the unit is able to emulate various devices within a home network and perform testing to
sectionalize problems. For example, if a subscriber cannot access the internet, the unit can emulate a
home computer and verify whether ISP connectivity is actually available. The unit can also perform a
variety of other connectivity-related and statistics-gathering functions. Using detachable modules, the
unit can be expanded to support different types of protocols and devices, such as the MoCA module
which provides an interface for in-home MoCA network testing.
Intro
architectures. It serves as a small and versatile in-home tester for technicians who are increasingly
required to troubleshoot networking issues from within the home, including the isolation of trouble to the
provider or subscriber sides of the network.
System
To use the unit and this documentation effectively, you should have some knowledge of network
architectures, especially Ethernet-based networks typically found in the home. While this document
attempts to explain unit functionality in reasonable detail, it cannot substitute for a basic understanding of
networking principles. If you are new to networking and related technologies, consider additional training
before attempting to use the unit and/or understand this document.
10/100
1.2.2 User prerequisites
1.2.3 Base unit features
Specs
IP/Video
NOTE: Your unit may or may not include all of the features described here, dependent upon your
licensing agreement with Spirent. Please contact Spirent for more information.
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Intro
Wi-Fi
10/100
•
Ethernet and IP connectivity testing - With its 10/100 interface, the unit can link to an Ethernet
network at any standard transport device such as a home router, hub, or Ethernet switch. Once
linked, the unit can join an IP network and perform testing such as ping, traceroute, and internet
webpage access. These abilities make the unit ideal for verifying connectivity within the home and
isolating problems to either the provider or subscriber networks.
•
Wi-Fi testing - The unit includes a Wi-Fi interface that can sync with wireless devices using 802.11b,
including support for WEP security. Similar to Ethernet testing, the Wi-Fi interface allows you to join a
wireless network and perform IP-based testing to verify connectivity and sectionalize issues.
•
IP video analysis - The unit is able to join a video stream and measure video quality and channel
change time. In this fashion, it can emulate a set-top box (STB) and provide a comprehensive
evaluation of IPTV quality. It can also bridge an existing stream on a link for passive monitoring. For
example, it can be placed between a home router and a real STB to passively monitor the video
communications between the devices, even while the video is simultaneously displaying on a TV.
•
Expansion of features with modular hardware - The unit is designed for expansion by attaching
feature-specific modules, such as the MoCA module for testing of home MoCA networks. For more
information on available modules, please contact Spirent. For more information on the operation of
any specific module, see the documentation for that module.
System
1.2.4 Front panel controls
IP/Video
Specs
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LED indicators
Intro
Power on/off
Wi-Fi
antenna
Strap mount
Tech-X Flex
CHARGE
Wi-Fi
ERRORS
[System]
Back
0: Record Manager
1: 10/100 Admin Port
2: Set Date and Time
3: Auto Sleep Mode
4: Version Info
5: Battery Status
6: Channel Guide/Network Setup
7: Download Channel Guide
8: Wireless ON/OFF
MoCA
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F2
F3
F1
Exit
System
F4
Arrow keys
ENTER
Backlight
EXIT
Help
GHI
ABC
JKL
DEF
MNO
PQRS
TUV
WXYZ
N1
HELP
Alphanumeric
keypad
Specs
N1
Function keys
IP/Video
Enter
Wi-Fi
Touchscreen
display
10/100
DATA
System
SYNC
Figure 1-1 Front panel controls
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Table 1-1
Tech-X Flex™
Front panel feature descriptions
Intro
Wi-Fi
10/100
System
IP/Video
Indicator
Function
Power on/off
Powers the unit on and off, and is also used to place the unit into sleep mode (see
Powering on/off and sleep mode on page 1-9).
LED indicators
See LED indicators on page 1-6.
Strap mount
See Attaching the strap on page 1-11.
Wi-Fi antenna
See Attaching the Wi-Fi antenna on page 1-10.
Enter
Engages the active control on the screen, such as a button or a text entry box.
Exit
Halts the current action or test, often returning the display to the previous screen.
Backlight
Adjusts the brightness of the display backlight.
Help
Used as a backspace on the text entry pad. Future versions will include onscreen
help launched with this button.
N1
Used to enter special characters on the text entry pad, such as periods.
Function keys
Used to select the active test interface and/or functional area, such as the Wi-Fi
interface or the System configuration menu.
Arrow keys
Provide navigational control over numerous display items, such as scroll bars,
multi-item lists, parameter entry screen controls, tabs, and more.
Alphanumeric
keypad
Used for text entry.
1.2.5 LED indicators
Specs
Tech-X Flex
SYNC
1-6
DATA
ERRORS
CHARGE
1: Introduction
Tech-X Flex™
Indicates the status of the link over the active interface. For example, when using the WiFi interface, the LED indicates the status of the Wi-Fi link. The general behavior is as
follows:
• Solid green - The unit is properly linked and/or synchronized with a comparable farend device. For the 10/100 interface, the LED is solid green any time the interface is
configured with IP information, but does not necessarily indicate that the information is
valid and routable.
• Red - The unit is attempting to configure the active interface and/or link with a far-end
device.
DATA
Flashes when sending or receiving data over the active interface. For example, when
using the 10/100 interface, the LED flashes when an Ethernet frame is sent or received.
ERRORS
Indicates errors at the data link level on the active data stream. For example, on the
10/100 interface, the LED may indicate Ethernet frame CRC errors.
CHARGE
Indicates power source and charging status, as follows:
Specs
• Solid red - Unit is connected to an external power source and the battery is charging
• Solid green - Unit is connected to an external power source and the battery is nearly
or fully charged
• Off - Unit is not connect to external power (unit on or off) and/or the unit has no battery
installed
Note that the unit includes a system feature for reporting detailed information about
battery status. For more information, see Battery Status on page 4-4.
Wi-Fi
SYNC
10/100
Function
System
Indicator
Intro
LED indicator description
IP/Video
Table 1-2
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1.2.6 Base unit physical interfaces (ports)
Ethernet (10/100) port 1
Ethernet (10/100) port 2
Intro
Wi-Fi
1-2
10/100
Figure 1-2 Base unit right side
Mic/headset jack
USB port
AC power/charge
System
IP/Video
12V
2A
Figure 1-3 Base unit left side
Specs
Note the following:
1-8
1: Introduction
Modules have their own physical interfaces. See the documentation for the respective module for
more information.
•
The two Ethernet interfaces are used for 10/100 testing and for administrative functions on the unit,
such as upgrading firmware.
•
The 2.5 mm mic/headset jack and USB port are for future use.
1.3 General product handling and operation
10/100
This section provides basic information for general operation. For most functions and tests, the buttons,
display, and other components operate in a similar fashion. Once you become familiar with general
operation, you should be able to set up and run most functions and tests, referring to this document only
as necessary for specific technical details, contained elsewhere in this document.
Wi-Fi
•
Intro
Base Unit User Guide Issue 1
1.3.1 Powering on/off and sleep mode
When the unit is off, the power button turns it on. When the unit is on, the power button prompts you
whether to power off the unit or to place it into sleep mode. Sleep mode allows the unit to save power but
return to active testing more quickly than a full boot up. To restore the unit from sleep mode, press the
power button once again. Note that the restoration process causes the unit to recheck module and
licensing status, after which it returns the screen to the default menu, not necessarily the menu that was
active when sleep mode was activated.
IP/Video
The unit supports automatic sleep mode activation after a specified amount of idle time. For more
information, see Auto Sleep Mode on page 4-4.
System
Tech-X Flex™
1.3.2 Attaching, detaching, and handling modules
placed into sleep mode. Failure to do this could result in damage to the module
or base unit firmware. For more information on initiating sleep mode, see
Powering on/off and sleep mode on page 1-9.
NOTE: To prevent damage to the module bay and to keep electrical connections clean, you should
keep the module placeholder (the “dummy” module) installed when no module is in use. New
units are shipped with the placeholder attached.
Modules are fastened to the base unit using fastener screws attached to the upper “feet” of the unit. To
remove a module, loosen/disengage the two screws and gently pull the module from its electrical
1: Introduction
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Specs
CAUTION: Before attaching or detaching a module, the unit must be powered off or
Base Unit User Guide Issue 1
Tech-X Flex™
connection. Likewise, to attach a module, gently press the module into the base unit to seat the electrical
connection, then finger-tighten the screws.
Intro
Fastener screws
Wi-Fi
10/100
Module
System
Figure 1-4 Rear of unit with a module installed, showing the fastener screws
IP/Video
Once a module is attached and has booted up, a menu corresponding to the module functionality will
appear over the F1 function key. For example, when the MoCA module is attached, the F1 menu shows
“MoCA.” If no module is attached, the F1 key shows no menu.
1.3.3 Attaching the Wi-Fi antenna
Specs
The antenna should be attached before using the Wi-Fi interface. The base of the antenna screws onto
the unit by hand. Note that the process is easier if the antenna is straightened while attaching and
detaching:
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Intro
Tech-X Flex™
Wi-Fi
CHARGE
10/100
Figure 1-5 Attaching the antenna
Figure 1-6 Antenna positioned for typical use, following attachment
1.3.4 Attaching the strap
A strap with a hook is provided to hang the unit while working. To attach the strap, first make sure that the
buckle is facing up, then slide the open end around and through the strap mount at the top of the unit:
1: Introduction
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Specs
IP/Video
System
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(To hook)
Intro
Strap end
Wi-Fi
Tech-X Flex
10/100
SYNC
DATA
ERRORS
CHARGE
Figure 1-7 Sliding the open strap end through the strap mount
Next, feed the open end through the bottom of the buckle as shown in the following figure:
System
Buckle
(To hook)
IP/Video
Strap end
Specs
Figure 1-8 Feeding the strap through the buckle
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The unit display includes touchscreen functionality which allows you to operate most display controls by
touching the screen. You should use a plastic stylus or a similar device. It is recommended to avoid using
your fingers because it is difficult to control selections with precision.
Intro
1.3.5 About the touchscreen display
CAUTION: Never use a sharp or metallic object which will damage the screen. Likewise,
1.3.6 Selecting the active interface
While testing with the unit, the first step is to select the appropriate interface with one of the function
keys, such as the 10/100 or Wi-Fi interface, or perhaps another interface associated with an attached
module. The interface and any associated hardware remain active only while testing in the respective
area continues. If you switch to a different interface, the previous interface shuts down and loses its IP
configuration, if any. For example, if you switch from the Wi-Fi interface to the 10/100 interface, the Wi-Fi
interface will shut down and any IP configuration will be lost.
IP/Video
An exception exists with the Wi-Fi interface, which can be optionally configured to remain active all the
time. For more information, see Wireless ON/OFF on page 4-9.
System
For new units, units with new firmware, or units with a new battery, a calibration of the touchscreen
should be performed. For more information, see Calibrate Touchscreen on page 4-10.
10/100
Wi-Fi
do not use a ballpoint pen, pencil, or any other writing device which will mar
the screen.
1.3.7 Starting a function or test
Specs
To run any function or test, the following steps generally apply:
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1. Using the function keys or the touchscreen, select the correct menu/interface.
Intro
A function key selects the
function/test/menu directly above
8: Wireless ON/OFF
Wi-Fi
MoCA
F1
Wi-Fi
F2
10/100
F3
System
F4
10/100
2. Using the up/down arrows, number pad, and/or touchscreen, select the desired menu item and
possibly submenu items to activate the desired function/test.
System
3. For tests that require input parameters, adjust those parameters as necessary, using the navigation
arrows and/or touchscreen. For free-form text entries, place the cursor in the field and press any
number key to produce the text entry window:
IP/Video
Specs
Using the touchscreen and/or the number keys, enter the desired data. Note the following:
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The text entry pad is similar to a standard text message device, where you must press a key
multiple times to cycle through the associated letters. For example, to enter a “b”, press the “2”
key three times quickly, then pause.
•
The N1 key allows you to enter special characters, such as a period.
•
The Help button on the physical keypad acts as a backspace.
Intro
•
NOTE: The unit is designed to be controlled by either the keypad or the touchscreen, or a combination
of both. You should become familiar with both methods of unit control, because you may find
that a combination of the two provides the most efficiency.
Wi-Fi
4. Press the appropriate button to start the respective action, normally “Start” or “OK.”
1.3.10 Interpreting results
In some cases, this document provides results samples and references to industry standards for pass/fail
criteria. None of this information should be construed as a recommendation or mandate on how any
given organization should interpret results. In all cases, you should consult local and corporate protocol
for the standards by which you interpret results. This document does not intend in any way to serve as an
authorized or approved standard for the operation and maintenance of any telecommunications network.
1.4 Maintenance
The only maintenance task that should be performed by users is battery replacement. For all other
maintenance requirements, return the unit to Spirent. Do not remove the cover of the unit during battery
replacement or at any other time. For more information on battery replacement, see Battery replacement
on page 1-16.
1: Introduction
1-15
System
Most tests allow you to save the results using the Save button on the results screen (F4 key). Results are
saved to the active record within the Record Manager. For more information, see Record Manager on
page 4-1.
IP/Video
1.3.9 Saving results
Specs
Tests can be stopped immediately with the EXIT key. Also, the Back button in the upper left corner of the
screen normally exits the current test. Some tests may require a small amount of shutdown time before
terminating completely.
10/100
1.3.8 Stopping a test
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1.4.1 Battery replacement
Users may perform field replacement of the battery pack. Note the following:
Intro
•
New battery packs should be ordered from Spirent.
•
Batteries contain hazardous contaminants and should be disposed of according to local regulations.
It may be illegal to discard batteries in the general trash.
To replace the battery pack
Wi-Fi
1. On the back of the unit, remove the two battery pack anchor screws, under the base of the kickstand.
Be careful not to accidentally remove the unit cover screws (see Figure 1-9).
10/100
Battery pack
screws
System
Unit cover
screw
Figure 1-9 Battery pack screws
IP/Video
2. Gently slide the battery pack from the bottom of the unit.
Specs
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3. Using the two screws at the base of the battery pack unit, remove the old battery from the plastic
holder and replace with the new battery,
4. Carefully reinstall the battery pack and screws.
NOTE: Do not overtighten the screws, which could cause the battery pack cover to crack.
1.5 Technical support
If you need product assistance or want to report problems with the product or the documentation, please
contact us.
Phone:
or
+1 301.444.2400
+1 800.321.0780 (USA)
Fax:
+1 301.444.1010
1: Introduction
Specs
Client Services
Spirent Communications
20324 Seneca Meadows Parkway
Germantown, MD 20876
USA
IP/Video
Figure 1-10 Removing the battery pack
System
10/100
Wi-Fi
Intro
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E-mail: systemssupport@spirent.com
Intro
Wi-Fi
10/100
System
IP/Video
Specs
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2: Wi-Fi Testing Menu
Wi-Fi testing on the unit includes:
•
Scanning for available wireless access points
•
Connecting to an existing network and obtaining IP information
•
Basic network-level testing such as ping, traceroute, and web browsing
All Wi-Fi testing is performed from the Wi-Fi menu. When this menu is active, all testing uses the Wi-FI
interface only. That is, no other interface will process test requests.
NOTE: You must have a Wi-Fi connection established before any other Wi-Fi functions become
available. Furthermore, when you leave the Wi-Fi menu, the Wi-Fi interface is shut down and
the existing connection, if any, is dropped, unless you have the unit configured to keep the
interface active. For more information, see Wireless ON/OFF on page 4-9.
Figure 2-1 Wi-Fi main menu
2: Wi-Fi Testing Menu
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2.1 Functionality note
Wi-Fi connection and testing is a purchasable option. Please contact Spirent for more information.
Intro
2.2 Wi-Fi overview
The following sections describe general information about the unit and Wi-Fi.
Wi-Fi
2.2.1 Wi-Fi support details
10/100
The unit supports connection to IEEE 802.11b (“Wireless-B”) networks using the 2.4GHz range. It
supports open access and Wired Equivalent Privacy (WEP) authentication, both WEP-40 (64-bit key)
and WEP-104 (128-bit key). If WEP is used, you must know the passphrase or key required by the target
network in order to gain access.
Most home network routers currently support 802.11b and use WEP authentication, if any. Therefore, the
unit is ideal for testing a wireless home network. By emulating a wireless PC in the home, you can
perform troubleshooting activities such as:
System
IP/Video
•
Verifying ISP availability and therefore ruling out the provider network as the cause of internet
connectivity problems. If the unit can access the internet but a subscriber PC cannot, it is likely that
the problem resides in the PC and/or its wireless interface.
•
Determine whether Wi-Fi “dead zones” exist at the premises and whether they are affecting network
performance. In some cases, wireless network troubles may be caused by equipment that is simply
out-of-range of the source.
Detailed technical information about Wi-Fi and 802.11b is beyond the scope of this document. If you are
having trouble connecting, see If you cannot connect (troubleshooting tips) on page 2-3.
Specs
2.2.2 Wi-Fi testing diagram
The following diagram shows a typical setup for Wi-Fi testing.
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Intro
Tech-X Flex™
Home
computer
Wi-Fi
Wireless
router
Ping
10/100
Provider
network/ISP
Ping, traceroute, web browsing
System
Figure 2-2 Typical Wi-Fi testing diagram
2.2.3 If you cannot connect (troubleshooting tips)
Specs
IP/Video
If you are in range of a wireless access point but cannot connect, verify the following:
2: Wi-Fi Testing Menu
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Intro
Wi-Fi
•
The Wi-Fi antenna is properly connected to the unit (see Attaching the Wi-Fi antenna on page 1-10.)
•
If entering all information manually, you have properly identified the network. Because this is an errorprone process, it is recommended that you use the auto-scan feature to find the network and
prepopulate many of the parameters (see Wi-Fi Setup > Scan on page 2-5.)
•
The network is not an “adhoc” network, which the unit does not support.
•
The access point supports 802.11b (“Wireless-B”) and is actively permitting connections with it. Most
home routers that advertise support for Wireless-G (802.11g) also support Wireless-B; however, it
may be possible to configure the router to disallow Wireless-B. If the router has been configured this
way, you will not be able to connect.
•
You have identified the proper security protocol in use and have the necessary information for
connection. If the wireless network is not secure, this is normally not an issue. However, if it uses
WEP, you must have the required WEP information. If it uses a different protocol that the unit does
not support, such as WPA or MAC address restrictions, you will not be able to connect.
10/100
2.2.4 About the connection history and “auto-connect” networks
System
When a wireless connection is successful, the unit stores the connection parameters in its internal history
up to 10 networks, according to the network SSID (the network name). Then, during subsequent
connection attempts, you can choose the network by SSID, which automatically populates all the original
connection parameters for quick access. If the unit connects to a network that has the same SSID as a
previous network, the new network settings overwrite the old ones. In other words, only one network can
be stored for any given SSID.
IP/Video
The unit also maintains a separate list of “auto-connect” networks, up to 15 networks, each of which
qualifies for automatic connection when the unit is powered up. Auto-connection is only attempted if
enabled in the system configuration. For more information, see Wireless ON/OFF on page 4-9.
Specs
When auto-connection runs, it first performs a scan of all available networks and checks the results for
any networks in the auto-connect list. If any are found, it attempts connection with them in order until a
connection is successful. If the unit cannot connect to any auto-connect networks in the scan results, it
then attempts connection with any remaining networks in the auto-connect list, even though they were
not detected by the scan.
NOTE: Once the unit is completely booted up, the SYNC LED will light green if a Wi-Fi connection was
successful. If you have multiple networks in the auto-connect list, you must use the Wi-Fi Setup
> Details function to determine which network the unit connected to (see Wi-Fi Setup > Details
on page 2-9). If the SYNC LED remains off, the unit failed to connect to any network.
The auto-connect network list can be edited by several means:
2-4
2: Wi-Fi Testing Menu
•
When you initiate a connection with Wi-Fi Setup > Connect or with the Connect shortcut from the
Wi-Fi Setup > Scan results, you can specify whether to add the network to the auto-connect list
following the connection attempt. The network is added whether or not the connection is successful.
(see Setup - Connect (Wi-Fi Setup) on page 2-7).
•
When you view the current connection details with Wi-Fi Setup > Details, you can use the Auto
On/Auto Off shortcut to add/remove the network from the list, respectively.
•
When you list all auto-connect networks with Wi-Fi Setup > View Auto-Connect Networks, you can
use the Delete shortcut to remove the network from the auto-connect list (see Wi-Fi Setup > View
Auto-Connect Networks on page 2-10.)
Intro
Base Unit User Guide Issue 1
Wi-Fi
Tech-X Flex™
2.3 Wi-Fi Setup
Wi-Fi Setup > Connect on page 2-6
•
Wi-Fi Setup > Details on page 2-9
•
Wi-Fi Setup > View Auto-Connect Networks on page 2-10
System
•
2.3.1 Wi-Fi Setup > Scan
The Scan function auto-detects all wireless networks within range of the unit and lists them on the
display. Once the list is produced, you can select the desired network and use the Connect shortcut to
connect. This method of connecting to a wireless network is preferred because:
•
You can ensure that you are connecting to the correct network on the correct channel. In denselypopulated areas, it is not unusual for multiple wireless networks to be available within any given
residence, including networks with the same SSID (name).
•
When the connection action is initiated, the unit prepopulates many of the parameters which would
otherwise need to be entered manually with potential for error.
•
Even if the network is familiar and/or you know all the parameters, the Scan function will verify that it
is actually available.
Once you successfully connect to the network through the Scan function, it is added to the history of
networks where it is available for the manual connection process (see Wi-Fi Setup > Connect on
page 2-6).
2: Wi-Fi Testing Menu
2-5
IP/Video
Wi-Fi Setup > Scan on page 2-5
Specs
•
10/100
The Wi-Fi Setup menu contains all the functions associated with finding and connecting to Wi-Fi
networks, including:
Base Unit User Guide Issue 1
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Setup - Scan (Wi-Fi Setup)
Intro
The Wi-Fi Scan requires no setup parameters. The process launches immediately following the menu
selection
Results - Scan (Wi-Fi Setup)
Wi-Fi
The scan lists all networks within range of the unit, including the SSID (name), signal strength, and
channel number for each network. For more information on these fields, see the descriptions under Wi-Fi
Setup > Details on page 2-9.
10/100
System
Figure 2-3 Wi-Fi Scan results
IP/Video
Results screen shortcuts:
Specs
•
Connect - Launches the Wi-Fi Connect function for the selected network (see Wi-Fi Setup > Connect
on page 2-6)
•
Details - Displays details of the selected network, similar to those displayed when you request the
details of a currently-connected network (see Wi-Fi Setup > Details on page 2-9)
•
Refresh - Reruns the scan
•
Save - Saves the Scan results (see Record Manager on page 4-1)
2.3.2 Wi-Fi Setup > Connect
The Connect function attempts a connection with a wireless network according to the specified
parameters. If you used the Wi-Fi Setup > Scan function results to launch the Connect, many of the
parameters are automatically populated. For this reason, the Scan function is generally recommended as
a prerequisite.
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NOTE: If you have trouble connecting, see If you cannot connect (troubleshooting tips) on page 2-3.
Intro
Once the unit successfully connects, the network parameters are saved in memory under the respective
SSID (name).
Setup - Connect (Wi-Fi Setup)
Description
SSID
(Service Set Identifier) Network name.
Channel Number Channel used by the network, typically 1 to 11 with variances possible based on the
country of operation and applicable regulations. A Wi-Fi connection is based on a
single channel which you must have correctly specified.
Network Type
Type of network:
INFRASTRUCTURE - A centralized network where the unit will negotiate with a
single access point that manages the network overall.
NOTE: Connection to “adhoc” Wi-Fi networks is currently not supported.
Security Type
Type of security in use on the network:
Specs
IP/Video
• WEP-64 - Wired Equivalent Privacy using a 40-bit key.
• WEP-128 - Wired Equivalent Privacy using a 104-bit key.
• NONE - No security (open access)
10/100
Parameter
Wi-Fi
Connect (Wi-Fi Setup) - Setup parameters page 1
System
Table 2-1
2: Wi-Fi Testing Menu
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Table 2-2
Tech-X Flex™
Connect (Wi-Fi Setup) - Setup parameters page 2
Intro
Parameter
Description
Key Type and Key
Type of key and the key itself, as follows:
Wi-Fi
• If Key Type = HEX, the Key must be a hexadecimal number. A hex digit
occupies four bits, so for WEP-64, a hex Key must be 10 digits (40 bits total).
For WEP-128, a hex Key must be 26 digits (104 bits total).
• If Key Type = PASSPHRASE, the key must be the appropriate string that can
be converted to the correct key using standard WEP algorithms. For WEP-64,
a passphrase Key must be 5 characters/digits. For WEP-128, a passphrase
Key must be 13 characters/digits.
10/100
WEP Authentication Type of initial authentication used by the wireless access point:
System
• OPEN - Effectively no authentication to associate and connect; however, all
communications following the connection will be WEP-encrypted and
therefore the unit must still have the correct key specified.
• SHARED - Requires matching keys to establish the initial connection, which
involves a more detailed handshake transaction between the devices.
Afterwards, all communications are WEP-encrypted similar to open
authentication.
NOTE: This setting does not affect how you specify the Key Type and
Key. It controls how the unit attempts initial negotiations only. Both
open and shared WEP require a valid key.
IP/Video
WEP Key Slot
Table 2-3
Specs
2-8
WEP key slot.
Connect (Wi-Fi Setup) - Setup parameters page 3
Parameter
Description
Auto-Connect
Specifies whether to add this network to the internal auto-connect list when the
connection is launched, ON (yes) or OFF. For more information, see About the
connection history and “auto-connect” networks on page 2-4.
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Base Unit User Guide Issue 1
Wi-Fi
Intro
Tech-X Flex™
Results - Connect (Wi-Fi Setup)
The unit reports whether the connection was successful or not. If the connection is successful, the SYNC
LED lights as solid green. If the connection failed and you don’t know why, see If you cannot connect
(troubleshooting tips) on page 2-3.
NOTE: After connection, you must obtain an IP address if you want to do any IP-based testing. For
more information, see IP Network Setup on page 5-1.
IP/Video
2.3.3 Wi-Fi Setup > Details
This function reports the details of the currently-active Wi-Fi connection. Results include:
Table 2-4
System
10/100
Figure 2-4 Wi-Fi Connect parameters (Page 1)
Details (Wi-Fi Setup) - Results
Description
SSID
(Service Set Identifier) Network name, as configured in the wireless router.
MAC Address
The hardware address of the physical interface at the wireless access point. This
should be a unique identifier of the hardware.
Mode
Network type, normally MANAGED. Adhoc networks are not supported.
2: Wi-Fi Testing Menu
Specs
Result
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Table 2-4
Tech-X Flex™
Details (Wi-Fi Setup) - Results
Intro
Result
Description
Security
Type of security in use by the network:
• NONE - No security (open access)
• WEP - Wired Equivalent Privacy
Wi-Fi
10/100
Signal Strength
Signal power level.
Channel Number
Channel used by the network, typically 1 to 11 with variances possible based on
the country of operation and applicable regulations. A Wi-Fi connection is based
on a single channel which you must have correctly specified when attempting to
connect.
Auto-connect
Indicates whether the network is on the auto-connect list (see About the
connection history and “auto-connect” networks on page 2-4).
2.3.4 Wi-Fi Setup > View Auto-Connect Networks
System
This function displays the current list of auto-connect networks. You can use the Delete shortcut to
remove the selected network from the list. For more information, see About the connection history and
“auto-connect” networks on page 2-4.
IP/Video
2.4 IP Network Setup
IP Network Setup allows you to assign IP routing information to the unit in order to perform IP-based
testing. This function operates similarly to other interfaces; however, note that when launched from the
Wi-Fi menu, the assigned IP information applies to the wireless interface/connection only.
For more information on IP Network Setup parameters and results, see IP Network Setup on page 5-1.
Specs
NOTE: The unit must have an active wireless connection before IP Network setup is available (see WiFi Setup on page 2-5).
2.5 Ping
Ping testing over the Wi-Fi interface is similar to other interfaces. For more information, see Ping on
page 5-4.
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2.6 Traceroute
Intro
Traceroute testing over the Wi-Fi interface is similar to other interfaces. For more information, see
Traceroute on page 5-5.
NOTE: The web browser is a purchasable option. Please contact Spirent for more information.
Specs
IP/Video
System
10/100
Use of the web browser over the Wi-Fi interface is similar to other interfaces. For more information, see
Web Browser on page 5-6.
Wi-Fi
2.7 Web Browser
2: Wi-Fi Testing Menu
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Intro
Wi-Fi
10/100
System
IP/Video
Specs
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3: 10/100 Testing Menu
With the 10/100 testing menu, the unit is able to join a 10/100 Ethernet link and perform the following
functions and tests:
•
IP address retrieval/assignment (See IP Network Setup on page 5-1)
•
IP ping (See Ping on page 5-4)
•
Traceroute (See Traceroute on page 5-5)
•
Internet web page request (See Web Browser on page 5-6)
•
IP video testing (See IP Video testing on page 5-7)
•
Ethernet bridging and passive testing (See Passive testing on page 3-4)
Figure 3-1 10/100 main menu
NOTE: On the unit, you can use either 10/100 port for single-ended tests such as ping and traceroute.
For more information, see About the 10/100 ports and connections on page 3-2.
3: 10/100 Testing Menu
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3.1 Functionality note
Intro
Your unit may or may not include all the functionality described in this section, dependent upon your
licensing agreement with Spirent. Please contact Spirent for more information.
3.2 About the 10/100 ports and connections
Wi-Fi
The unit has two physical 10/100 ports which are connected internally by a functional Ethernet switch.
Therefore, when performing single-ended tests such as ping or traceroute, you may use either port.
When setting up an Ethernet bridge for passive tests, the order of the ports is likewise not important.
NOTE: On the physical port, the unit is able to auto-detect the receive and transmit channels; therefore
you may use straight-through or crossover Ethernet cables for any application.
10/100
3.3 10/100 testing diagram
System
The following diagram shows a typical setup for active, single-ended tests. For more information on the
setup for bridged, passive testing, see Passive testing on page 3-4.
IP/Video
Home
computer
Specs
Home
router
Ping
Provider
network/ISP
Ping, traceroute, web browsing, IPTV video testing
Figure 3-2 Typical 10/100 testing diagram
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IP Network Setup allows you to assign IP routing information to the unit in order to perform IP-based
testing. This function operates similarly to other interfaces; however, note that when launched from the
10/100 menu, the assigned IP information applies to the 10/100 interface/connection only.
Intro
3.4 IP Network Setup
NOTE: The unit must be connected to a suitable access device before attempting IP Network setup
(see 10/100 testing diagram on page 3-2).
Wi-Fi
For more information on IP Network Setup parameters and results, see IP Network Setup on page 5-1.
Ping testing over the 10/100 interface is similar to other interfaces. For more information, see Ping on
page 5-4.
10/100
3.5 Ping
Traceroute testing over the 10/100 interface is similar to other interfaces. For more information, see
Traceroute on page 5-5.
3.7 Web Browser
NOTE: The web browser is a purchasable option. Please contact Spirent for more information.
Specs
Use of the web browser over the 10/100 interface is similar to other interfaces. For more information, see
Web Browser on page 5-6.
3.8 IP Video Tests
NOTE: Video testing is a purchasable option. Please contact Spirent for more information.
Active IP video testing on the 10/100 interface is similar to other interfaces. For more information, see IP
Video testing on page 5-7.
3: 10/100 Testing Menu
IP/Video
System
3.6 Traceroute
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3.9 Passive testing
NOTE: Passive testing is a purchasable option. Please contact Spirent for more information.
Intro
Passive testing allows non-intrusive testing on a bridged Ethernet link. The following sections describe
passive testing and bridge setup in more detail.
Wi-Fi
3.9.1 Unit setup for passive testing
10/100
Because the two 10/100 ports are joined internally by a functional Ethernet switch, the unit is inherently
capable of bridging an Ethernet link when placed in the middle. With a bridged link, the unit can passively
monitor traffic between the ports (that is, the traffic flowing across the “bridge”), such as during a passive
measurement of video quality. The ports are always active; therefore, the bridge capability is always
active, with the monitoring feature activated when a passive test is run.
System
With a passive test, the unit does not send any traffic on the link, nor does it interfere with any traffic
passing through the link. However, an active link will be naturally disrupted when the unit is physically
placed in the middle. For a passive test to run, it is required that the desired traffic is activated or restored
between the bridged endpoints before the testing begins. Using the example of passive video testing,
consider the following typical setup:
IP/Video
Active video stream
Set-top box
Ethernet
ISP / IPTV
video service
Specs
Router/
gateway
Passive
monitoring
Figure 3-3 Bridged (passive) video testing
To set up the video test in this example, you should:
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Tech-X Flex™
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1. Connect the physical wires between the endpoints, from router-to-unit and unit-to-STB.
3. Set up and run the desired test on the unit.
The following notes apply:
•
Following successful IP Network Setup, you can also perform single-ended active tests while the link
is bridged, in either direction. In the previous example, you should be able to ping the STB if you
know its IP address, as well as anywhere upstream, including the internet.
•
You can use either crossover or straight-through Ethernet cables for any connections to the unit.
Wi-Fi
Intro
2. Verify that communications between the bridged endpoints are restored. In this example, you should
be able to see the video on the TV.
The passive video quality test operates identically to the active version, with the following exceptions:
•
Instead of actively joining a video stream, the unit monitors an existing stream on the bridged link.
Therefore, the video stream must be active between the bridged endpoints before the test can begin.
•
Because the unit itself does not need to join the stream, the passive test supports both unicast and
multicast streams. Existing stream traffic can be identified by the specified IP address and port alone.
Specs
IP/Video
For detailed information on the video QoS test parameters and results, see Video Quality of Service
(QoS) on page 5-8.
System
Select 10/100 menu > Passive Tests > Video Quality of Service.
10/100
3.9.2 Passive Video Quality of Service (QoS)
3: 10/100 Testing Menu
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Intro
Wi-Fi
10/100
System
IP/Video
Specs
3-6
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4: System Menu
The System menu provides access to general system configuration.
Figure 4-1 System main menu
4.1 Record Manager
Select System > Record Manager.
The Record Manager is used to create, delete, and view record files, which are special files used to store
test results. When you invoke the “Save” function in a results screen, they are saved to a record file. For
non-continuous, self-terminating tests, the full results set is saved at the end of testing. For continuous
tests, you can control when saving is active, during which time a full results set is saved following the end
of each reporting interval.
At any given time, a single record file is considered the active file, which is where results are saved when
you invoke the Save function. If you have never created any record files, the unit uses a “DEFAULT”
record file until you specify otherwise. If you do not have the need for multiple record files, the default
record may be sufficient for general use.
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NOTE: All records and associated results remain on the unit until manually deleted. A unit shutdown
will not delete record data.
Intro
The unit has no specific maximum to the number of record files or the amount of results that any record
can contain. However, it does have a certain overall limit related to the constraints of physical memory. A
general rule which might be useful is to have no more than 30 record files on the unit at once, each with
no more than 20 sets of test results. The actual numbers can vary, though, especially considering the
type of results you are saving. For example, the results data set from a video test is many times larger
than a ping test.
Wi-Fi
The Record Manager lists record files in the Name column and indicates the currently-active file in the
Active column. The actions that may be invoked by the respective function key include:
Table 4-1
Record Manager functions
10/100
Function
Description
New
Creates a new record file. The name can have any alphanumeric name, often reflecting a
work order number or a customer location.
System
NOTE: Do not begin a record name with a period (N1 key), otherwise it will not
appear in the Record Manager.
IP/Video
Delete
Deletes the selected file. This action cannot be undone.
Active
Makes the select file the active file, where results will be stored during subsequent save
actions.
View
Opens the selected file for viewing in the form of a tree view of results. Normally, a results
set includes one branch with shows details on the original test setup, with a second branch
indicating the success or failure of the operation with additional details as applicable.
Specs
4.2 10/100 Admin Port
Select System > 10/100 Admin Port.
This function assigns IP data to the internal management interface of the unit. It is similar to the IP
Network Setup for the 10/100 test interface, except that it provides access to the internal management of
the unit, rather than the test interface. If successful, this function allows management communication
through the same physical 10/100 ports used for 10/100 testing.
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Tech-X Flex™
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Intro
Currently, this function is used as a prerequisite for management activities such as firmware upgrades
and channel guide imports. It does not provide general access to the operating system of the unit. For
more information on firmware upgrades, see Update Firmware on page 4-10.
4.3 Set Date and Time
The date and time are used to timestamp all saved results in the Record manager. They are also used for
various internal functions, described in this document elsewhere as appropriate.
Wi-Fi
Select System > Set Date And Time.
Date - YYYY-MM-DD
•
Time - HH:MM:SS
To set the date or time, select either parameter and press a number on the keypad to initiate the numeric
entry screen. You must enter all characters that are requested, using leading zeros as necessary to pad
empty spaces. For example:
09:10:00
Specs
IP/Video
...would set the time to 9:10 a.m. Note that the unit uses 24 hour time. For example, 9:10 p.m. would be
set as 21:10:00.
System
•
10/100
The date and time must be entered using the following formats:
Figure 4-2 Setting the date and time
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4.4 Auto Sleep Mode
Select System > Auto Sleep Mode.
Intro
This function sets the maximum amount of idle time after which the unit automatically enters “sleep
mode” in order to save battery power. It does not apply when the unit is powered by an external source.
For more information on sleep mode, see Powering on/off and sleep mode on page 1-9.
Wi-Fi
4.5 Version Info
Select System > Version Info.
10/100
This function provides information about hardware and firmware versioning currently applicable to the
unit, including the attached module, if any. This information may be required when obtaining technical
support from Spirent. It may also be useful for verification before and/or after firmware upgrades.
System
IP/Video
Figure 4-3 Version Info
Specs
4.6 Battery Status
Select System > Battery Status.
This function provides detailed information about the battery and current charging conditions. For the
general user, the Estimated Remaining Capacity percentage may be the most useful.
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4.7 Channel Guide/Network Setup
Parameters
Description
Use Guide
Indicates whether a channel guide is currently active for video test setup. For
more information, see About channel guides on page 4-7.
Guide Name
Name of the active channel guide, only applicable when Use Guide is set to
Yes. The field allows you to select from the guides currently on the unit, if any. If
the field is blank, no channel guides have been imported. For more information,
see About channel guides on page 4-7.
Channel Format
If Use Guide = Yes, this setting determines how channels from the guide are
initially sorted in a video test setup screen, either by number or abbreviation. In
either case, the number or abbreviation comes directly from the guide.
IGMP Version
Version of IGMP to use for multicast join/leave requests. This must reflect an
IGMP type in use on the network where the request is made.
4: System Menu
1 - IGMP version 1
2 - IGMP version 2
3 - IGMP version 3
D - Dynamic. The unit attempts to monitor existing IGMP traffic on the
network to determine the type in use.
Specs
•
•
•
•
IP/Video
Options include:
10/100
Channel Guide/Network Setup - Page 1 parameters
System
Table 4-2
Wi-Fi
This function allows you to set common parameters for all video testing, including testing on different
interfaces. In most cases, these are global configuration parameters that are set once and remain static
for subsequent testing. In cases where the same parameter appears in a video test setup screen, the
setting here acts as the default.
Intro
Select System > Channel Guide/Network Setup.
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Table 4-3
Tech-X Flex™
Channel Guide/Network Setup - Page 2 parameters
Intro
Parameters
Description
Int’l Code
Country/continent code. This specification allows the analysis to adjust the
quality metric scores according to statistical data available in different parts of
the world.
Wi-Fi
Options include:
10/100
•
•
•
•
•
•
•
Coder Class
NA - North America
SA - South America
EU - Europe
AF - Africa
AS - Asia
JP - Japan
AUS - Australia
System
Video coder class, which describes the ability of the stream to tolerate packet
loss with respect to perceived quality. The coder class is determined by two
contributing factors:
IP/Video
• Codec - Some codecs, particularly older codecs, are very sensitive to packet
loss and degrade very quickly with small amounts of loss.
• Error correction and concealment - A number of loss mitigation techniques
may be employed to conceal packet loss, typically involving coordination
between the video server and client where checksum and other validation
methods allow missing data to be supplemented.
The specified value determines how heavily the analysis weights the effects of
packet loss. For example, if you specify an operation at high rates of loss, any
detected loss will have less of an effect on final quality scores. This is normally a
static setting on any given network that does not change between tests.
Specs
Options include:
•
•
•
•
4-6
A - Stream can operate over networks with up to 20% packet loss
B - Operation with up to 10% loss
C - Operation with up to 5% loss
D - Operation with up to 0.5% loss
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Within the channel guide file itself (not on a video test screen), a sample entry might appear as follows:
...where the element names intuitively denote each respective parameter, such as  and
. To be functional, a channel guide must be well-formed and conform to the proper schema.
For more information on schemas and channel guide generation, please contact Spirent.
IP/Video
System
10/100

001
ESPN
239.255.1.101
3002
UDP
MPEG2
FIXED
GOP_C
15
0
2
0

Wi-Fi
A channel guide provides a shortcut for specifying IP video channels during video testing. When the unit
joins and/or monitors a video stream for testing, it requires the IP address and port of that stream. If you
do not have a channel guide on the unit, you must enter the address and port manually. However, if you
do have an active channel guide that includes the respective channel, it allows you to select a simple
channel number or a more intuitive channel abbreviation, such as CNN or HBO. The unit then looks up
the address and port in the guide instead of requiring a manual entry. A channel guide also provides a
series of other default testing parameters for each channel, such codec type and media stream
information.
Intro
4.7.1 About channel guides
To import channel guides to the unit, you must follow the procedures described in this section. Channel
guides cannot be imported by any other means.
NOTE: The procedures in this section are an abbreviated version. If you need further assistance,
please contact Spirent Technical Support.
The import requires two basic steps:
4: System Menu
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Specs
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Tech-X Flex™
1. Place the channel guides on a networked computer that has an approved FTP server running. This
section describes how to install and set up that server.
2. Run the import function on the unit.
Intro
Note the following:
•
You must be able to connect the unit to the FTP server host computer over Ethernet/IP
•
All existing channel guides on the unit are deleted or overwritten during the import
•
Spirent recommends a maximum of eight channel guides during an import
Wi-Fi
To install and set up the FTP server
Currently, the only approved FTP server is FileZilla, a free, open-source application available at
http://filezilla-project.org/ at the time of this writing. The FileZilla server runs on the Windows platform
only. To set up FileZilla on a host computer:
10/100
1. Download the FileZilla server package (not the client).
2. Launch the package and install according to default settings, unless customization is desired.
3. Open the Server Interface, normally with a new icon on the desktop. For new installs, you can leave
the password blank in the Connection prompt.
System
4. In the interface window, select Edit > Users.
5. In the Users window, click Add to add a new FTP user account, which the unit will use to retrieve
channel guide files.
6. In the Add user account window, specify a user name (such as techxflex) and click OK.
IP/Video
7. Back in the Users window, click the General page link, and specify a password if desired.
Important! The password is optional, but if you specify one, you must remember what it is when
launching the import on the unit.
8. In the Users window, click the Shared folders page link, then click Add to specify the folder where
the channel guide files are stored.
Important! When you run the import, every file from this folder is imported from the unit. Therefore,
the folder should contain channel guide files only.
Specs
9. In the Users window, click OK to save the new user.
To run the import on the unit
With FileZilla running on the host computer:
1. Connect the 10/100 interface of the unit to the network where the host computer resides.
2. On the unit, select System > 10/100 Admin Port and obtain an IP address for the admin interface
(see 10/100 Admin Port on page 4-2).
3. On the unit, select System > Download Channel Guide and enter the requested information, as
follows:
4-8
4: System Menu
The IP address or DNS name of the host computer where the FTP server application
is running.
Port
The port on which the FTP server is listening for requests. The default is 21 but can
be changed in the FTP server setup.
User ID
The name of the user account that you set up in the previous procedure.
Password
The password of the user account, if one was specified.
4. On the unit, click Start to initiate the import.
If the import is successful, you can select System > Channel Guide/Network Setup and verify the
import by looking at the list in the Guide Name field.
If the import fails, check the FTP server setup and the network connection between the unit and the
host computer. Either device should be able to ping the other.
4.8 Download Channel Guide
Select System > Download Channel Guide.
IP/Video
For more information on importing channel guides to the unit, see Importing channel guides to the unit on
page 4-7.
10/100
Wi-Fi
Server
Intro
Base Unit User Guide Issue 1
System
Tech-X Flex™
4.9 Wireless ON/OFF
If set to ON, this setting causes the following to occur:
•
When the unit is powered up, a Wi-Fi connection is automatically attempted, based on the internal list
of auto-connect networks. For details on how auto-connection works, see About the connection
history and “auto-connect” networks on page 2-4.
•
The current Wi-Fi connection remains active while other menus and interfaces are in use. If the autoconnection was successful, it is immediately available for use and remains active as long as the unit
is within range.
If set to OFF, the Wi-Fi interface can still be used for testing; however, its general behavior is identical to
other interfaces. For more information, see Selecting the active interface on page 1-13.
4: System Menu
4-9
Specs
Select System > Wireless ON/OFF.
Base Unit User Guide Issue 1
Tech-X Flex™
4.10 Calibrate Touchscreen
Select System > Calibrate Touchscreen.
Intro
This function calibrates the touchscreen display for optimal response. Calibration should be done after
firmware upgrades, after battery replacement, or if the screen response begins to degrade after heavy
use.
Wi-Fi
The process requires you to touch the screen in several places with a stylus or other approved device.
Follow the instructions on the screen.
4.11 Licensed Options
10/100
Select System > Licensed Options.
This function reports which optional features are currently enabled for the base unit and modules (if any),
which may be required when seeking technical support. It also allows you to manually enable features by
entering valid key codes, which is may be required to enable licensed features on a new unit. To enter a
key code, press Update Key (F1) and enter the key exactly as provided by Spirent. Note the following:
System
IP/Video
•
For licensing changes to take effect, you must reboot the unit or cycle it through sleep mode. For
more information, see Powering on/off and sleep mode on page 1-9.
•
The unit requires a unique key code for each licensed feature. For example, to enable both the web
browser and IP video testing, you need to enter two different codes.
•
You do not need to enter anything except the code itself. The unit will recognize the feature to which it
applies and then list that feature as enabled.
•
A key code is specific to a unit and will not work on any other unit.
•
Key codes must be provided by Spirent. In some cases, the codes required for your licensed feature
set are shipped in the package with the unit. If you have trouble with the codes or require new codes
for any reason, please contact Spirent.
Specs
4.12 Update Firmware
Select System > Update Firmware.
This function initiates the firmware upgrade process. You must supply the IP address of a networked host
on the active 10/100 link from which the unit will retrieve the firmware package. Note the following:
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4: System Menu
Base Unit User Guide Issue 1
•
The host that contains the firmware must be set up in a specific manner. Please contact Spirent for a
separate document that provides details on this setup and other information about firmware
upgrades.
•
The 10/100 admin port must be set up before this menu command becomes available (see 10/100
Admin Port on page 4-2).
Intro
Tech-X Flex™
Specs
IP/Video
System
10/100
Wi-Fi
Please contact Spirent for additional information about upgrading firmware.
4: System Menu
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Base Unit User Guide Issue 1
Tech-X Flex™
Intro
Wi-Fi
10/100
System
IP/Video
Specs
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Tech-X Flex™
Base Unit User Guide Issue 1
5: IP and Video Testing
This section describes the suite of IP and video (IPTV) functions available on the unit. These tests are
available over various interfaces on the unit, including the Wi-Fi and Ethernet interfaces, and modular
interfaces such as MoCA. Not all tests are available for all interfaces; see the respective documentation
for specific testing support.
Once an interface is correctly configured with routable IP information, testing from that interface should
be generally identical to any other. For example, ping testing from the Wi-Fi interface should be identical
to ping testing from the Ethernet interface, except that it is launched from a different menu. Therefore, the
information is consolidated here and applies generally to any interface that supports the respective test.
To configure an interface with routable IP information, use the IP Network Setup function (see IP Network
Setup on page 5-1). Once setup is successful, the following tests may be available, depending upon test
support of the respective interface:
•
IP Network Setup on page 5-1
•
Connection Information on page 5-3
•
Ping on page 5-4
•
Traceroute on page 5-5
•
Web Browser on page 5-6
•
IP Video testing on page 5-7
NOTE: Your unit may or may not include all the functionality described in this section, dependent
upon your licensing agreement with Spirent. Contact an account manager for more information.
5.1 IP Network Setup
This function is used to configure the active interface as necessary to join an IP network. For example, if
you are using the 10/100 menu, this function configures the 10/100 interface with the IP routing
5: IP and Video Testing
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Base Unit User Guide Issue 1
Tech-X Flex™
information required to send and receive IP traffic. For any interface, IP Network Setup is a required
prerequisite to any test that sends and/or receives IP data over that interface.
Intro
IP Network Setup must be performed each time the unit is started up, for the interface(s) that you intend
to use. Furthermore, you may need to run the setup again after switching test menus, if the menu change
activates a different interface on the unit. To facilitate frequent setup actions, the unit supports DHCP,
which is the preferred method of configuration if a DHCP server is available. By using DHCP, you can
more easily assure that valid IP routing information is assigned which does not conflict with any other
host on the network.
Wi-Fi
Before attempting IP Network Setup, the unit must be linked up with the proper access device, according
to interface type. For example, if you are performing 10/100 testing, the unit should be connected to a
switch or router with an Ethernet cable. Or, for Wi-Fi testing, the unit should be within range and
synchronized with an active Wi-Fi node.
10/100
NOTE: If you disconnect the unit and reconnect it to another network, you should rerun the network
setup. IP information for one network may not be routable on another.
5.1.1 Setup - IP Network Setup
System
Table 5-1
Parameter
Type
IP Network Setup - Setup parameters
Description
Method for assigning IP information:
IP/Video
• STATIC - Static assignment. If you select this method, the unit will request the
static address information.
• DHCP - DHCP assignment. If a DHCP server is available, all IP information is
assigned automatically. DHCP is a common method for IP address
assignment within a home network and most home network routers include a
DHCP server.
NOTE: If the unit fails to get an address with DHCP, see Results - IP
Network Setup on page 5-3.
Specs
If you select static assignment, the unit requires you to manually enter the IP address, subnet mask,
default gateway, and DNS server. The unit will accept any information that you specify and attempt to use
it for active test traffic, whether it is routable or not. Therefore, you should be sure to enter valid
information, otherwise subsequent IP-based testing will fail. In addition, note the following:
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5: IP and Video Testing
Base Unit User Guide Issue 1
•
Ensure that you have specified generally valid IP information. For example, the unit cannot assign an
address of 0.0.0.0 because it is not valid for IP communications.
•
For static assignment, the DNS server address is optional. However, if you do not specify a valid
server, you must know the target IP address for any IP-based tests. That is, the unit will be unable to
resolve domain names such as www.google.com.
Intro
Tech-X Flex™
The unit is properly connected to an active, networked device. For example, when using the 10/100
interface, the Ethernet cable must be properly connected. Or, for the Wi-Fi interface, the unit must be
within range of an active wireless node.
•
The target network has an active DHCP server. In a home network, the DHCP server is normally
incorporated with the home router, in which case you may need to log into the router to ensure that
the DHCP server has not been disabled. See the router documentation for more information.
IP/Video
System
•
10/100
The results screen displays either the assigned IP information, or a failure message if the process failed.
If a DHCP operation fails, check the following:
Wi-Fi
5.1.2 Results - IP Network Setup
Specs
Figure 5-1 Successful IP Network Setup
5.2 Connection Information
This function reports the IP information that is currently assigned to the active interface and is identical to
the results screen from a successful IP Network Setup. For more information, see IP Network Setup on
page 5-1.
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Tech-X Flex™
5.3 Ping
Intro
IP Ping is a basic connectivity test that verifies whether a specific IP address can be reached. It sends a
set of ICMP echo requests to an IP address and reports whether replies are successfully received. The
request is sent via the active interface of the unit and requires that routable IP information is assigned to
that interface. For more information, see IP Network Setup on page 5-1.
5.3.1 Setup - Ping
Wi-Fi
Table 5-2
Ping - Setup parameters
10/100
Parameter
Description
Destination
Address
Target address for the ping request, either a dotted IP address or a URL if a DNS
is available. For example:
208.22.58.142
www.google.com
System
5.3.2 Results - Ping
Along with details about each individual ping request, the unit also reports the following summary
information:
IP/Video
Table 5-3
Specs
5-4
Ping - Results
Result
Description
Packets Sent
Number of ping requests sent to the address
Packets Received
Number of ping requests reported as successfully received
Packets Lost
Percentage of ping requests that were lost (Packets Sent - Packets
Received)
Approximate Round Trip
Average time for a ping requests to reach its destination and then for the
unit to receive the success report
5: IP and Video Testing
Base Unit User Guide Issue 1
Wi-Fi
Intro
Tech-X Flex™
5.4 Traceroute
This test is the standard ICMP traceroute function that sends three traceroute requests to a destination
address and reports every router “hop” along the path, up to 30 hops. The results provides a topological
view of the route that the packets used to reach the destination.
5.4.1 Setup - Traceroute test
Table 5-4
Traceroute - Setup parameters
Parameters
Description
Destination IP
Address
Target address for the traceroute request, either a dotted IP address or a URL if
a DNS is available. For example:
208.22.58.142
www.google.com
5: IP and Video Testing
5-5
Specs
IP/Video
The request is sent via the active interface and requires that routable IP information is assigned to that
interface. For more information, see IP Network Setup on page 5-1.
System
10/100
Figure 5-2 Successful Ping results
Base Unit User Guide Issue 1
Tech-X Flex™
5.4.2 Results - Traceroute test
Intro
The unit reports the IP address of each sequential hop along the path to the target, along with the
roundtrip time required for each hop to receive the request and the unit to receive acknowledgement.
Because three independent requests are sent, each hop shows three different roundtrip times. An
asterisk appears if a time cannot be determined, such as a response timeout when a network element
cannot or will not return a traceroute acknowledgement.
Wi-Fi
10/100
System
Figure 5-3 Successful Traceroute results
5.5 Web Browser
IP/Video
NOTE: The web browser is a purchasable option. Please contact Spirent for more information.
The web browser allows you to access web pages from the internet and view them on the screen. It may
be especially useful for verifying that internet access is available, beyond a simple ping test. If a
residential subscriber cannot view a web page but you can with the unit, you can normally conclude that
the trouble exists with the subscriber’s web browser, computer, or home network configuration. It may
also be used to verify that a DNS is available.
Specs
The web browser is similar to a browser used on a desktop computer, except that the smaller screen may
require more use of the scroll bars. Furthermore, aside from basic hyperlinks, most webpage controls
may not work correctly. In some cases, complex pages with extensive internal scripting may not display
correctly or at all, so it is recommended that you use simple, fast-loading web pages to perform tests. In
summary, the browser is intended as a testing tool, not as a fully-functional interface to the internet.
To access the web browser, the active interface must be configured with valid, routable IP information.
For more information, see IP Network Setup on page 5-1.
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Tech-X Flex™
Base Unit User Guide Issue 1
5.5.1 Setup - Web Browser
Web Browser - Setup parameters
Intro
Table 5-5
Parameters
Description
URL
Target address of the web page to load, either a dotted IP address or a URL if a
DNS is available. For example:
Wi-Fi
208.22.58.142
www.google.com
Note the following:
10/100
• When entering a URL, case is unimportant because all characters are
converted to lower case when the browser is launched.
• The unit remembers the recent addresses you entered.
IP video testing support includes:
•
Subjective quality assessment of viewer experience
•
Comprehensive statistics on multimedia transport streams
•
Video channel change times
Video testing is supported on IP multicast streams using the MPEG codec. During testing, the unit joins
the stream and emulates an IPTV subscriber, providing a comprehensive view of the subscriber
experience.
IP/Video
System
5.6 IP Video testing
Specs
NOTE: Depending upon the test interface, passive testing of video quality for unicast and multicast
streams may also be available.
Specific video functions include:
5: IP and Video Testing
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Base Unit User Guide Issue 1
Intro
•
Channel Guide/Network Setup on page 4-5 (System menu)
•
Video Quality of Service (QoS) on page 5-8
•
Channel Change Time on page 5-30
Tech-X Flex™
5.6.1 Video Quality of Service (QoS)
NOTE: Video testing is a purchasable option. Please contact Spirent for more information.
Wi-Fi
This test provides subjective no-reference quality scores on a specific IPTV channel stream, along with a
set of network parameters, picture frame statistics, and other transport stream information.
10/100
For a single-ended, active test, the unit must emulate a video endpoint and join a multicast stream, after
which it performs the quality assessment on the traffic sent directly to it. Some interfaces, such as the
10/100 interface, provide a bridging/mirroring mechanism where the unit can be placed between two
devices and passively monitor an existing stream. In this case, the unit does not join the stream itself and
therefore supports the measurement of unicast streams as well. For more information on how the
passive bridging process works with the Ethernet interface, see Unit setup for passive testing on
page 3-4.
System
For more details on how the quality assessment works, see How the analysis works - An overview on
page 5-27.
NOTE: The analysis focuses primarily on the data captured from the MPEG transport stream. For more
information about MPEG transport, see the information under Digital video concepts overview
on page 5-20, including About MPEG transport on page 5-23.
IP/Video
Setup - Video Quality of Service
Specs
NOTE: If the unit has an active channel guide, the display will first present a channel selection screen
when the test setup is initiated. After channel selection, the normal setup screen will appear,
with the certain parameters prepopulated, such as the IP Address and Port. The use of a
channel guide, if available, is generally recommended. For more information, see Channel
Guide/Network Setup on page 4-5.
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5: IP and Video Testing
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Wi-Fi
Intro
Tech-X Flex™
Description
Channel Num
If a channel guide was used, the channel number and abbreviation that was
selected in the previous screen. If no channel guide is active, these fields do not
appear. For more information on channel guides, see About channel guides on
page 4-7.
Channel Abbr
IP Address
IP address of the video stream. If you selected a channel from the channel guide,
this field is automatically populated.
The IP address specified must reflect the destination IP address for video stream
packets; that is, the first address contained in the IP packet headers. For a
multicast stream, this will be a multicast IP address, not an IP address of a host
on the network under test. For a unicast stream, this must be the IP address of
the destination device on the network, such as an STB. For a discussion on
multicast packet addressing and transport versus unicast, see About IP multicast
on page 5-25.
5: IP and Video Testing
5-9
System
Parameter
IP/Video
Video QoS test - Setup parameters
Specs
Table 5-6
10/100
Figure 5-4 Video QoS Setup - Page 1 (with channel guide)
Base Unit User Guide Issue 1
Table 5-6
Tech-X Flex™
Video QoS test - Setup parameters
Intro
Parameter
Description
IP Port
UDP port of the video stream. Similar to the IP Address, this must be the
destination port in the UDP packet header. If you selected a channel from the
channel guide, this field is automatically populated.
Wi-Fi
Optionally, you can select As IP Add from the drop-down list which indicates to
ignore the port and use the IP address exclusively for identifying video stream
packets. In the case of unicast streams where packets are addressed to a
network device such as an STB, it can be more difficult to determine the UDP
port than the IP address of that device. Therefore, this option allows traffic
analysis based on IP address alone. While the STB may be receiving some data
that is not part of the video stream, it is likely that most traffic will be video data
that qualifies for analysis.
10/100
System
Duration of the test in seconds, or Continuous to run the test until manually
stopped.
Interval
Interval at which to report a full set of current measurement results, applicable to
continuous tests only.
Encapsulation
Method
Encapsulation type of the stream under test.
IGMP Version
Version of IGMP to use for multicast join/leave requests. This must reflect an
IGMP type in use on the network where the request is made.
IP/Video
Duration
• RTP
• UDP
Options include:
•
•
•
•
Specs
Codec
1 - IGMP version 1
2 - IGMP version 2
3 - IGMP version 3
D - Dynamic. The unit attempts to monitor existing IGMP traffic on the network
to determine the type in use.
Video codec used for the stream under test.
• MPEG2
• MPEG4
• H264
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5: IP and Video Testing
Tech-X Flex™
Options include:
• F or FIXED - The jitter buffer uses a constant fixed delay. The jitter buffer is
bounded by a nominal and maximum delay, where the nominal delay dictates
the actual delay and the maximum delay dictates the maximum number of
packets that can be stored in the jitter buffer.
• A or ADAPTIVE - The jitter buffer is bounded by a minimum, nominal and
maximum delay, where the minimum delay dictates the minimal accepted jitter
buffer delay, nominal delay dictates the starting delay and the maximum delay
dictates the maximum delay of the jitter buffer. The maximum number of
packets that can be stored in the jitter buffer is a set fraction of the maximum
delay.
GOP Type
Video coder group of pictures (GOP) structure, representing the frame sequence
in use on the stream with respect to I, P, and B frames. This value is used only as
a default if the actual frame types and GOP structure cannot be dynamically
detected from the stream.
Options include:
• A - I-frames only, for example:
III…I
• B - One I-frame followed by P-frames, for example:
IPPP...PIPPP...
• C - One I-frame followed by P- and B-frames with two B-frames between each
pair of anchor frames, for example:
IBBPBBP...BBIBBP...
• D - All P-frames, for example:
PPPP...P
• E - One I-frame followed by P- and B-frames with one B-frame between each
pair of anchor pictures, for example:
IBPBP...BIBP...
For more information about MPEG pictures, see About IP multicast on
page 5-25.
5: IP and Video Testing
5-11
Wi-Fi
Type of jitter buffer emulation used.
10/100
Jitter Mode
System
Description
IP/Video
Parameter
Intro
Video QoS test - Setup parameters
Specs
Table 5-6
Base Unit User Guide Issue 1
Base Unit User Guide Issue 1
Table 5-6
Tech-X Flex™
Video QoS test - Setup parameters
Intro
Parameter
Description
GOP Length
Number of frames in a group of pictures (GOP) on the stream, related to the
GOP type. This is essentially the I-frame update interval; that is, the number of
frames from one I-frame to the next. This value is used only as a default if the
actual frame types and GOP structure cannot be dynamically detected from the
stream.
Wi-Fi
Range:
1 - 100
Loss Sensitivity
10/100
This defines how much the quality assessment should be sensitive towards
packet loss and discards. A higher value indicates the video stream is more
sensitive to packet loss/discard. When set higher, the calculation model will
respond more rapidly to packet loss on the network under test, and packet loss
will have a greater impact on the calculated score. If set lower, the results will be
less affected by packet loss. This setting makes the analysis tunable for different
varieties of encoders and various network environment conditions.
System
Concealment Level This parameter defines the effectiveness of the packet loss concealment
algorithm use by the encoder. A higher value indicates a better PLC algorithm.
This setting helps compensate for reduced packet loss due to regeneration by
technologies such as forward error correction (FEC). In other words, it affects
how sensitive the quality assessment is to packet loss, with some similarity to the
loss sensitivity setting. A higher setting indicates that overall packet loss will
affect the quality score less. A setting of zero or none indicates no concealment,
meaning that packet loss will have the most impact to video quality, with respect
to this parameter's influence.
IP/Video
Valid values are:
0 to 50
Complexity
Specs
This parameter defines the video content coding factor. A higher value indicates
the video stream can be encoded using a lower bit rate to achieve a given
quality.
Valid values are:
-50 to 50
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Tech-X Flex™
Video QoS test - Setup parameters
Parameter
Description
Original Quality
Original picture quality. This value represents the subjective quality of the video
before encoding, which is the theoretical maximum that the quality ever could be
after encoding, transport, and decoding.
Intro
Table 5-6
Base Unit User Guide Issue 1
Video coder class, which describes the ability of the stream to tolerate packet
loss with respect to perceived quality. The coder class is determined by two
contributing factors:
• Codec - Some codecs, particularly older codecs, are very sensitive to packet
loss and degrade very quickly with small amounts of loss.
• Error correction and concealment - A number of loss mitigation techniques
may be employed to conceal packet loss, typically involving coordination
between the video server and client where checksum and other validation
methods allow missing data to be supplemented.
The specified value determines how heavily the analysis weights the effects of
packet loss. For example, if you specify an operation at high rates of loss, any
detected loss will have less of an effect on final quality scores. This is normally a
static setting on any given network that does not change between tests.
10/100
Coder Class
System
256 - 1280, proportional to the 1.0 to 5.0 MOS range, scaled by a factor of 256.
For example, a value of 1242 is equivalent to a MOS of 4.85.
Wi-Fi
Valid values are:
Valid values are:
IP/Video
A - Stream can operate over networks with up to 20% packet loss
B - Operation with up to 10% loss
C - Operation with up to 5% loss
D - Operation with up to 0.5% loss
Specs
•
•
•
•
5: IP and Video Testing
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Table 5-6
Tech-X Flex™
Video QoS test - Setup parameters
Intro
Parameter
Description
International Code
Country/continent code. This specification allows the analysis to adjust the
quality metric scores according to statistical data available in different parts of the
world.
Valid values are:
Wi-Fi
•
•
•
•
•
•
•
10/100
NA - North America
SA - South America
EU - Europe
AF - Africa
AS - Asia
JP - Japan
AUS - Australia
Results - Video Quality of Service (VQM test)
System
Test results are presented in three different screens, each of which has two different pages. Use the
appropriate function key to switch between screens. Note the following:
IP/Video
Specs
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5: IP and Video Testing
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All quantitative measurements apply to the reporting period only. No measurements are cumulative.
•
Unless indicated otherwise, any reference to “packets” means MPEG packets, not IP packets.
Table 5-7
Intro
•
Video QoS results - Summary results, Plot tab
Description
MOS graph
Displays graph of calculated V-MOS, A-MOS, and AV-MOS, which updates regularly
for continuous tests. The graph assumes a fixed score of 4.0 as passing and 3.0 as
marginal. The standards for any given architecture may differ. For more information on
MOS scoring, see About MOS on page 5-28.
IP/Video
System
10/100
Result
Wi-Fi
Tech-X Flex™
Table 5-8
Specs
Figure 5-5 MOS graph
Video QoS - Summary results, MOS tab
Result
Description
IP Addr
IP address and port of the media stream, specified at test launch.
Port
MOS Scores
5: IP and Video Testing
See About MOS on page 5-28.
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Base Unit User Guide Issue 1
Table 5-9
Tech-X Flex™
Video QoS - Summary results, Stream/Expert Analysis tab
Intro
Result
Description
Codec Type
Stream type, as defined in ITU Spec ISO/IEC 13818-1.
Image Size
Horizontal resolution, indicating the left-right size of the image, in pixels.
-and-
Wi-Fi
Vertical resolution, indicating the top-bottom size of the image, in pixels.
Image Type
Type of the image.
Valid values are:
10/100
• SDTV
• HDTV
System
Loss
Percentage of the overall quality degradation that can be attributed to network packet
loss.
Jitter
Percentage of the overall quality degradation that can be attributed to jitter buffer
discards.
Codec Type
Percentage of the overall quality degradation that can be attributed to video
encoder/decoder selection.
Delay
Percentage of the overall quality degradation that can be attributed to delay.
IP/Video
Table 5-10 Video QoS - Stream results, Stream Metrics tab
Specs
Result
Description
Frames
Total number of frames received, by type.
Lost
Total number of packets lost containing data for the respective frame type; for
example, the total number of packets lost containing I-frame data. These results
are packet counts, not frame counts.
NOTE: If packets for one frame type show an inordinate amount of loss
compared to others, there may be a problem with network congestion
and/or configuration. For example, some NEs may be configured to
discard video B-frame data during periods of heavy congestion.
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Discards
Total number of packets discarded by the jitter buffer emulator containing data for
the respective frame type; for example, the total number of packets discarded
containing I-frame data. These results are packet counts, not frame counts.
Impairments
Total number of frames errored, by type. A frame is considered errored if a single
packet containing data for it is lost or discarded.
FEC Effect
Calculated effectiveness forward error correction if it were applied to the stream.
Opt FEC Blk Size
Number of packets in an FEC block which is used when calculating the FEC
effectiveness.
Opt FEC Crct Pkts Number of correctable packets in an FEC block which is used when calculating
the FEC effectiveness.
Table 5-11 Video QoS - Stream results, Stream Description tab
Result
Description
GOP Type
GOP structure type of the stream. If the structure was detected by the analysis,
this value represents the detected structure. Otherwise, it represents the default
specified at test launch.
For details on possible values, see Setup - Video Quality of Service on
page 5-8.
GOP Length
GOP length on the stream; that is, the total number pictures in a single GOP. If
the structure was detected by the analysis, this value represents the detected
structure. Otherwise, it represents the default specified at test launch.
Receive Rate
Speed of frames received, in kbits/sec.
Pk Rcv Rate
Peak speed of frames received, in kbits/sec.
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IP/Video
System
Ratio of peak packet receive rate to the mean receive rate.
Specs
Peak/Mean Rcv
Rate
Wi-Fi
Description
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Result
Intro
Table 5-10 Video QoS - Stream results, Stream Metrics tab
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Table 5-12 Video QoS - Stream results, Video Scores tab
Intro
Result
Description
VSTQ
Video service transmission quality. This is a codec-independent measure related
to the ability of the bearer channel to support reliable video.
Valid values are:
Wi-Fi
0 - 100
VSPQ
Video Service Picture Quality. This is a codec-dependent measure of the
subjective quality of the decoded video stream. It is equivalent to a V-MOS score,
using a different scoring range.
0 - 100
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System
Gap VSPQ
Video Service Picture Quality during gap state periods. This is a codec-dependent
measure of the subjective quality of the decoded video stream. It is equivalent to a
V-MOS score, using a different scoring range.
Burst VSPQ
Video Service Picture Quality during burst state periods. This is a codecdependent measure of the subjective quality of the decoded video stream. It is
equivalent to a V-MOS score, using a different scoring range.
VSMQ
Video Service Multimedia Quality. This is a codec-dependent measure of the
subjective quality of the decoded audio and video stream. It is equivalent to an
AV-MOS score, using a different scoring range.
IP/Video
Valid values are:
0 - 100
ESNR
Estimated average peak signal-to-noise ratio value for pictures in the stream, in
dB. This value is derived based on other metrics and is not measured directly.
Specs
Table 5-13 Video QoS - Transport results, Stream Metrics tab
Result
Description
Pkt Discard Rate
Number of packets discarded. Packets may be discarded by the jitter buffer
emulator for the following reasons, similar to an actual jitter buffer:
• The buffer is too full to handle all incoming packets
• A packet arrives too late to contribute to the media presentation
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Result
Description
OOS Pkt Rate
Number of video/audio stream packets that arrived out of sequence, as detected
by the jitter buffer emulator.
Burst Loss Rate
Average percentage of media independent units (MIUs) lost and/or discarded
during burst periods.
Wi-Fi
NOTE: For further information about bursts and gaps, see About gap and
burst states on page 5-29.
Average burst period length in milliseconds.
Gap Loss Rate
Average percentage of media independent units (MIUs) lost and/or discarded
during gap periods.
Gap Length
Average gap period length in milliseconds.
Description
MPEG Sync Loss
Number of times that the sync byte of a packet header was errored or not present
for two consecutive transport stream packets.
MPEG Sync Byte
Err
Number of times that a transport stream sync byte did not appear following a 188byte or 204-byte transport stream packet.
MPEG Cont Err
Number of times that the continuity count of a received packet did not increment
by one, as compared to the previous packet. The continuity count is a 4-bit field in
the packet header that increments from 0 - 15 for each transmitted packet,
resetting at zero as necessary. Continuity count errors are normally caused by lost
or out-of-sequence packets.
MPEG Trnspt Err
Number of packets that indicated a transport error, by means of the transport error
bit in the packet header. The transport error bit is set to "1" when at least one
uncorrectable bit error exists in the packet.
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IP/Video
Result
Specs
Table 5-14 Video QoS - Transport results, MPEG Stats tab
System
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Intro
Table 5-13 Video QoS - Transport results, Stream Metrics tab
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Table 5-14 Video QoS - Transport results, MPEG Stats tab
Result
Description
Intro
Wi-Fi
PCR Repetition Err Number of times that the interval between PCR (program clock reference)
transmissions exceeded 100 ms, if the discontinuity indicator is not set. The PCR
is used as a time synchronization tool between the encoder and decoder. If the
discontinuity indicator is not set, the encoder expects a 100 ms or smaller interval
between PCRs. Both the PCR and discontinuity indicator are part of the packet
header.
PTS Err
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Number of times that the PTS (presentation time stamp) repetition period
exceeded 700 milliseconds. The PTS is part of a packet header and indicates the
exact moment where a video frame or an audio frame has to be decoded or
presented to the user respectively. It is important for synchronization of the audio
and video streams.
Table 5-15 Video QoS - Transport results, Jitter/Delay Stats tab
System
Result
Description
MAPDV
The true average mean-absolute packet delay variation in milliseconds. This type
of measurement is sometimes referred to as jitter.
IP/Video
For more information on MAPDV, see About packet delay variation (PDV) on
page 5-29.
PPDV
The packet-to-packet delay variation in milliseconds, according to a calculation
model defined in RFC 3550.
For more information on PPDV, see About packet-to-packet delay variation
(PPDV) on page 5-29.
Specs
Digital video concepts overview
About basic video and audio compression
Compression techniques are vital to allow modern communication networks to handle the transmission
of packetized digital video. For example, without compression, a video stream with pixelized image
frames would require a large amount of data, far too much for efficient transport across networks to
multiple subscribers.
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Temporal redundancy - Adjacent video frames often have many similarities, especially with video of
still or slow-moving objects. In this case, sequential frames may have redundant information
expressed over time as the video is played.
In the end, the encoders/decoders effectively form a system where the technology is able to interpolate
redundant data, without the need to transmit it. This system allows for more efficient network capacity
utilization when transporting audio/video streams over communications networks.
Frame types
As part of the reduction in redundancy, the video is compressed and reorganized into three different
frame types, serving individual roles as follows:
•
I-frames (or “Intra pictures”) - I-frames are coded without reference to other pictures. That is, they
contain the full dataset required to render a video frame and do not interpolate based on references
to other frames. Therefore, they may employ compression to reduce spatial redundancy, but cannot
reduce temporal redundancy. I-frames are critically important for providing references to other frames
and serve as access points in the bitstream where decoding can begin. Because other frame types
do reduce temporal redundancy based on a dependence to the I-frames, the loss of I-frames in a
video stream has the most significant impact.
•
P-frames (or “Predictive pictures”) - P-frames are interspersed between I-frames and allow a
combination of spatial and temporal redundancy. They can use internal spatial coding like I-frames,
but they can also derive data through references to previous I and P-frames. Through this
referencing, a P-frame can render the picture without a full pixel-by-pixel dataset, using redundant
information presented in preceding frames.
•
B-frames (or “Bi-directional predictive pictures”) - B-frames are a further extension of the Pframe predictive methodology, except that they may reference preceding and/or following I and/or Pframes. The use of B-frames allows the highest degree of picture quality with the most efficient
compression. When a B-frame references a frame that comes after itself, the decoder must have
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Wi-Fi
•
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Spatial redundancy - Within any given video frame, certain data may be redundant, such as large
portions of the same color or geometrical design. In this situation, compression may be employed to
represent portions of the frame as smaller mathematical values, rather than expressing every single
pixel individually, when many pixels are the same.
System
•
IP/Video
Video compression involves multiple stages, beginning with the removal of spatial similarities from
individual frames using techniques similar to JPEG (Joint Photographic Experts Group) compression.
Then, similarities between adjacent frames are determined and removed from the stream, using complex
algorithms to reuse identical data that was already transmitted and to “predict” data where future
changes can be estimated. These processes serve to reduce the two primary forms of redundancy:
Intro
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Intro
received the referenced frame before the B-frame can be decoded, making the frame order different
from the actual display order. Therefore, B-frames can cause a delay in the decoding process,
because the decoder must buffer the input while reordering the frames for display. Of the three, the
loss of a B-frame generally causes the least impact to picture quality.
At the data level, a frame is divided into slices which represent horizontal sections of the frame. Each
slice is further divided into macroblocks which represent rectangular sections of the slice. This
organizational structure is the reason that digital video exhibits “rectangular” errors when data becomes
corrupted, rather than the general fuzz and/or static caused by a poor analog signal. For example:
Wi-Fi
•
If macroblock data is missing or corrupted, the video typically shows rectangles of missing picture on
the screen, amidst an otherwise clear picture. Likewise, if a whole slice can’t be rendered, a larger
rectangular portion is missing.
•
If whole frame data is missing or corrupted, the video may freeze on certain pictures altogether,
rendering the last known frame while waiting for new frame data.
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GOP types
System
For any video stream, a set of frames is called a group of pictures or GOP, with the specific sequence
known as the GOP structure. A common GOP structure would include one I-frame, followed by two Bframes, then followed by one P-frame, and so on, represented as “IBBPBBP…" The following figure
represents a simplified diagram of frame reference and interpolation, using a typical GOP structure:
IP/Video
Specs
I frames
P frames
B frames
Figure 5-6 Compressed video stream frames
Audio compression
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Audio compression has some similarity to video compression, in that techniques may be used to
eliminate redundant data. Furthermore, audio exhibits the concept of “masking,” where one frequency
may mask another and the human ear is unable to perceive it. Because it is unnecessary to transmit any
data for sounds that will never be heard, the removal of this data from the original audio stream provides
further possibilities for data reduction.
Intro
Tech-X Flex™
The MPEG standards refer broadly to a set of protocols for transporting compressed audio/video
programs over a communications network, such that a decoder can properly reconstruct the audio/video
programs at the destination. It is overseen by the Moving Picture Experts Group
(http://www.chiariglione.org/mpeg/).
System
A fundamental concept of MPEG transport is the “program,” the higher-level entity that end users receive
when they select a “channel.” Fully-decoded, an MPEG program is the entire dataset required to present
a single multimedia experience to the user, such as the complete and synchronized audio/video streams
required to watch a single IPTV channel.
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About MPEG transport
Wi-Fi
Additional details of encoding, decoding, and compression algorithms are complex and beyond the
scope of this document.
Specs
IP/Video
The preparation of the audio/video programs has two fundamental stages:
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Intro
Wi-Fi
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System
•
Elementary stream - The elementary stream is the basic compressed audio or video bitstream. In
the case of a video stream, this is the original content segmented into macroblocks, slices, and
frames, then packetized with header information required to reconstruct the stream at the far end. An
elementary stream is a single stream of video or audio only, relying on the transport stream layer to
associate it with other streams and create the concept of a program.
•
Transport stream - Once constructed, one or more elementary streams are packetized into a
transport stream that provides all the instructions necessary to identify the data associated with a full
program, synchronize with the encoder, and reconstruct and present the audio/video program
properly. The transport stream includes the program clock reference or PCR, which provides the
critical data required for the decoder to synchronize its internal clock with that of the encoder. Without
synchronization, the decoder would be unable to recreate the video with the same timing as it was
encoded. Furthermore, the transport stream includes information such as:
– Packet identifiers or PIDs - Used as unique identifiers for individual elementary streams, as well
as program-specific information as described below.
– Program map table or PMT - Lists the elementary streams in the transport stream and identifies
the respective program(s) to which they belong. A program includes one or more elementary
streams, typically one video elementary stream and one or more audio elementary streams.
– Program association table or PAT - Lists all the programs included in the transport stream, as a
high-level list of all programs available to the decoder (or in other words, channels available to the
end user). When a program is selected for decoding, the decoder uses the program identifier in
the PAT to look up the required streams in the PMT.
– Conditional access table or CAT - Includes pointers to the PIDs that contain the entitlement
control/management messages needed to unscramble audio/video content, useful for
subscription-based services where access is limited.
IP/Video
Once completed, a transport stream is a sequence of 188-byte MPEG packets, ready for encapsulation
and transport over a communications network. The header data of transport streams, as well as that of
packetized elementary streams, is extremely useful for performing audio/video quality analysis, and
therefore provides the great majority of data used to calculate quality scores and other metrics.
Specs
With respect to degradation that may be caused during transport, the impact on audio/video quality
depends heavily upon the specific portion of the transport stream that is affected. For example, at the
lowest level, a loss of macroblock data may only cause a momentary anomaly in the display, perhaps not
even perceptible by the viewer. At the other extreme, a loss of MPEG transport header data, such as a
loss of synchronization, can cause the complete loss of the video altogether. For this reason, modern
analysis techniques must carefully consider the nature of loss and its respective impact on quality.
Overall, it should be noted that the descriptions here are highly-simplified, provided as a general
overview only. The full architecture of a complete MPEG transport stream is multi-layered and very
complex, beyond the scope of this document to describe.
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IP multicast is a set of protocols that allows a single IP packet to be sent to multiple hosts (that is, “group
members”) without the need to send multiple redundant copies of the same packet from the source. It
serves to alleviate network congestion when multiple hosts need to receive the same traffic, such as the
case where multiple IPTV subscribers are watching the same channel and each will ultimately receive
the exact same data payload.
Intro
About IP multicast
Wi-Fi
Consider the following diagram, which represents a small network without multicasting:
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R1
R2
System
R5
IP/Video
R4
Figure 5-7 Hypothetical network without group multicasting
In the previous figure, three subscribers are watching the same channel. The shaded packets represent
the unicast IP streams required to deliver the service. The IP payload in each stream, however, is exactly
the same, resulting in a redundancy that creates congestion and scalability issues.
Alternatively, consider the following figure, which illustrates group multicasting:
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R1
Intro
R2
Wi-Fi
R5
R3
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R4
System
Figure 5-8 Hypothetical multicast network with multicasting and IGMP
IP/Video
In this example, the routers are multicast-aware and can make intelligent decisions about packet
forwarding. The routers control the forwarding of multicast packets, with those routers directly connected
to multicast group members using Internet Group Management Protocol (IGMP) to manage the
duplication and forwarding of packets to individual group members.
Specs
In a multicast-enabled network, multicast routers interact and dynamically maintain a logical tree for
routing multicast packets, in order to efficiently deliver the required packets to each subnet that requests
them. If no subscribers on a particular subnet are members of a given multicast group (for example, no
one on a particular subnet is viewing a particular audio/video stream), the network may automatically
adjust to avoid multicasting that stream to that subnet. Similarly, when a host on a subnet successfully
joins a group, the network will dynamically extend a branch of the respective multicast tree to the router
serving the host. In summary, therefore, multicasting improves transport efficiency both by eliminating
redundant packets from the same media source, and by eliminating the indiscriminate broadcast of any
packets to branches in the network that have no hosts requesting them.
Note that multicasting is a form of “selective broadcasting,” where packets from the source are simply
duplicated as necessary and forwarded onto the respective links, all the way down the multicast tree to
each requesting group member. IP multicast routers use specialized multicast routing protocols such as
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Protocol Independent Multicast (PIM) to build logical multicast trees and forward packets efficiently
between the multicast source and group members. Once multicast packets reach their destination
subnets, group members "listening" for packets with the specific IP multicast (destination) address will
receive and process the packets accordingly.
The IP address range of 224.0.0.0 - 239.255.255.255 is reserved for multicast packets. It should be
noted that these addresses are likely unroutable in a traditional sense on the destination subnets that
receive the packets. Rather, it is the suite of multicasting protocols that allows packets to be properly
forwarded and ultimately processed by the proper group member device(s). This is distinctly different
from unicast transmission, where IP packets are addressed for a specific source/destination pair and
exchanged exclusively between the two hosts.
Intro
Base Unit User Guide Issue 1
Wi-Fi
Tech-X Flex™
Quality measurement overview and additional results descriptions
•
Audio/video packet details - Comprehensive metrics describing the number of MPEG packets
received, lost, and discarded.
•
General audio/video stream information - Stream characteristics such as audio/video codec,
audio/video stream bit rate, video stream GOP size/structure, and video stream image size.
•
Degradation factors - Identification and quantification of the factors which have caused degradation
of the video signal, such as codec, packet loss, and packets discarded due to buffer underrun and/or
overrun.
•
General network metrics - Information on the overall packet transport network such as packet delay
variation and packet loss.
Quality is estimated based on general stream, packet, and frame characteristics that are known to have
a predictable impact on user experience. This methodology provides reliable measurements without the
need to decrypt a scrambled video signal. Packet loss is naturally the primary factor involved with
audio/video quality degradation, but the following types of considerations also affect quality calculations:
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IP/Video
The following metrics may be used to estimate the overall subjective quality of the audio/video stream,
some of which are also reported in the results:
Specs
How the analysis works - An overview
System
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The following sections describe the quality measurement process in more detail.
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Intro
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•
Other problems related to network impairments, such as packet delay variation and out-of-sequence
packets.
•
The inherent abilities of the codec and associated equipment to conceal network impairments such
as packet loss.
•
The structure and length of GOPs (MPEG Groups of Pictures), especially with regards to the varied
effects of packet loss on different frame types.
•
The bit rate and frame size (or resolution) used at the encoder, as smaller rates and lower resolutions
can degrade the quality of the image even if transport is flawless.
•
The impact of recency. Recency is the trend of human viewers to judge audio/video quality to be
lower immediately following a disturbance to the signal, and the subsequent trend for that perception
to improve gradually if time passes with no further disturbance.
•
Packet loss distribution. Bursty packet loss events in which consecutive packets are dropped have a
different effect on perceived audio/video quality than packet loss events in which single packets are
dropped and the time (or "distance") between the single loss events is significant.
•
Loss of synchronization between the audio and video signals.
System
While it does not measure signal-to-noise directly, the analysis does use codec and packet loss/discard
information to calculate an estimated peak signal/noise ratio (EPSNR). The EPSNR is then used as a
key input for quality score calculations.
About MOS
IP/Video
MOS (mean opinion score) is a numerical system used to grade the subjective perceptual quality of an
audio, video, or multimedia user experience. Originally based on ITU-T recommendations for the
evaluation of voice quality, it uses a scale of 1 - 5 to indicate viewer experience with the following typical
benchmarks:
Specs
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Score
Quality
Human perception of degradation
Excellent
Imperceptible. No degradation of video quality can be
detected by a human viewer.
Good
Perceptible. Degradation can detected, but does not
adversely impact the viewing experience.
Fair
Slightly annoying
Poor
Annoying
Bad
Very annoying or no stream present
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The software models the distribution of packet loss over the measurement duration, which allows for a
more detailed characterization of the packet loss experienced by the audio/video stream. This is a fourstate model in which two periods of loss exist, gap and burst periods, each of which has two states.
The stream is considered to be in a gap condition of loss when consecutive packet loss is less than or
equal to one packet. If two or more consecutive packets are lost, the stream is considered to be in a burst
condition. Following the entry into a burst period, 128 consecutive packets must be received in order to
return to the gap condition, a number determined though research of quality measurements. Note that
the successfully received packets will be considered to have arrived during a gap period.
Other test results
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About gap and burst states
Wi-Fi
Intro
MOS scoring is frequently produced by software algorithms that monitor video streams and attempt to
“emulate” a subjective viewer experience. Such software is intended to produce results that are similar to
MOS scores that would be recorded by actual human participants watching and evaluating the media.
...noting the use of absolute values. So, if a packet is expected to arrive at time1 but actually arrives at
time2, it has a PDV of | time1 - time2 |. Typically, individual PDVs are used for calculating an average for
multiple packets in a stream, or reporting the maximum PDV experienced during a measurement period.
NOTE: Packet delay variation is sometimes referred to as jitter. However, the use of PDV terminology
is preferred in this documentation due to its more specific definition.
About packet-to-packet delay variation (PPDV)
Packet-to-packet delay variation (PPDV) is a statistical calculation of delay variation, based on the
method described by the IETF RFC 3550. It differs from basic packet delay variation (PDV) which looks
at variations in arrival time overall, not necessarily variations between adjacent, sequential packets.
As an example, consider four sequential packets, whose delays in arrival are 40, 42, 38, and 39 msec
respectively. The delay variation of the second packet is 2 msec ( | 40 - 42 | ), the delay variation of the
third packet is 4 msec, and so forth. The measurements continue for all selected packets in the
measurement stream, with all measurements considered in the end for a calculation of statistical
variance.
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IP/Video
| Expected time - Arrival time |
Specs
Packet delay variation is a calculation based on the variation of a packet’s expected arrival time versus
its actual arrival time. Each packet has its own PDV, which is determined by:
System
About packet delay variation (PDV)
Base Unit User Guide Issue 1
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Note that the usage of PDV versus PPDV is a complex subject and is beyond the scope of this
document.
Intro
Additional video testing notes
About the IP address specified for testing
Wi-Fi
The IP address specified must reflect the destination IP address for video stream packets; that is, the first
address contained in the IP packet headers. For a multicast stream, this will be a multicast IP address,
not an IP address of a host on the network under test. For a unicast stream, this must be the IP address
of the destination device on the network, such as a set-top box (STB).
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About encrypted (scrambled) signals and frame type recognition
System
The analysis software does not perform any decryption of scrambled signals. For monitoring a scrambled
stream, this can affect the ability to recognize frame types because the type indicator data may be
encrypted as well. Because perceived effect of packet loss varies widely according to the type of frame
whose data was lost, the frame type is an important component when packet loss is evaluated. Therefore
the software exhibits the following behavior with regards to frame type recognition:
IP/Video
•
If the signal is not scrambled, the software should be able to recognize frame types according to
explicit data in the stream and precisely associate lost packets with the respective type.
•
If frame type data is encrypted but frame boundaries can be discerned, the software heuristically
attempts to determine frame type based on relative data size and expected patterns.
•
If frames cannot determined at all, the software uses default GOP structure and length information
specified when the analysis is launched to interpolate the probabilities of packet loss occurring within
any given frame type. Over time, if the defaults accurately reflect the GOP setup of the stream, the
measurements and estimations should be statistically correct.
Specs
While the lack of decryption by the software may appear initially as a limitation, it actually provides much
more flexibility with deployment and ease of maintenance. With the ability to interpolate encrypted frame
types, users are not required to maintain and deploy decryption algorithms that require processing time,
change periodically, and may be expensive and/or difficult to license.
5.6.2 Channel Change Time
NOTE: Video testing is a purchasable option. Please contact Spirent for more information.
The IPTV change channel test measures channel change time by measuring the time between IGMP
requests and resulting changes in the packet stream. The unit accomplishes this measurement by joining
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For more detailed information on the time calculation, see How channel change time is calculated on
page 5-32.
Intro
a multicast stream and initiating an actual channel change, emulating the behavior of IPTV subscriber
STB equipment.
With an active channel guide:
Figure 5-9 Change Channel Setup - Page 1 (with channel guide)
NOTE: The screen has a small display area and can only show a limited number of channels from the
guide at once. Remember to use the scroll bars on the table and/or the arrow keys on the key
pad to locate the desired channels. Furthermore, be sure that the From Channel and To
Channel at the bottom accurately reflect the channels you want to test.
Without an active channel guide:
The unit requires you to manually enter the following information for each channel:
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Specs
IP/Video
System
The unit presents a table with which you can select the two channels for the test. All other required
information is prepopulated from the channel guide, such as IP addresses and port numbers. For more
information on how the channels are used, see How channel change time is calculated on page 5-32.
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The Channel Change Time setup differs whether or not a channel guide is active. For more information
on channel guides, see Channel Guide/Network Setup on page 4-5.
Wi-Fi
Setup - Channel Change Time
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Intro
•
IP Address - IP address of the multicast stream
•
IP Port - UDP or TCP port of the stream, with respect to the Encapsulation Method
•
Encapsulation Method - Transport encapsulation used for the stream
•
Codec - Video codec type
Results - Channel Change Time
Wi-Fi
The test reports the channel change time in msec, along with other parameters used in the calculation.
For more information, see How channel change time is calculated on page 5-32.
How channel change time is calculated
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During a channel change test, the unit joins the first specified channel, leaves that channel, then joins the
second specified channel. During this process, four key events are used for the change time calculation,
as illustrated in the following figure:
Time
System
Channel A stream
First packet Ch. A
IP/Video
Multicast join
request - Ch. A
Channel B stream
Last packet Ch. A
LastA
Multicast leave
request - Ch. A
ML
First packet Ch. B
FirstB
Multicast join
request - Ch. B
MJ
Specs
Figure 5-10 Channel change calculation timeline
Referring to this figure, the basic formula for change time calculation is:
Time = (LastA - ML) + (FirstB - MJ)
...where the individual terms are temporal instances, not quantitative amounts of time. In other words,
channel change time equals time it takes to leave the first stream, plus the time it takes to join the second
stream, measured from the respective IGMP requests.
5-32
5: IP and Video Testing
Tech-X Flex™
Base Unit User Guide Issue 1
Channel Leave Time - Equals the (LastA - ML) term.
•
Channel Join Time - Equals the (FirstB - MJ) term.
Specs
IP/Video
System
10/100
Wi-Fi
•
Intro
For reference, the unit indicates the following test results:
5: IP and Video Testing
5-33
Base Unit User Guide Issue 1
Tech-X Flex™
Intro
Wi-Fi
10/100
System
IP/Video
Specs
5-34
5: IP and Video Testing
Tech-X Flex™
Base Unit User Guide Issue 1
6: Specifications
This section provides detailed information on physical components and specifications of the Tech-X Flex
base unit.
NOTE: Specifications are subject to change.
6.1 General specifications
Table 6-1
Physical specifications
Dimensions (H x W x D)
• 8.964 in x 4.208 in x 2.524 in
• 22.77 cm x 10.69 cm x 6.41 cm
Weight
2.0 lb. (0.91 kg)
Display
Color LCD with adjustable backlight. 320x420 pixels (1/4 VGA)
Case material
BAYBLEND FR-3000 HI ABS + PC (POLYCARBONATE)
Rubber components
TPU (DESMOPAN 9370A)
LED indicators
Sync, Data, Errors, Charge
Communications
interfaces
• 10/100 Base-T Ethernet
• IEEE 802.11b (“Wireless B”) Wi-Fi
• USB 2.0
Test interfaces
• 10/100 Base-T (x2)
• 802.11b (wireless)
6: Specifications
6-1
Base Unit User Guide Issue 1
Table 6-2
Tech-X Flex™
Power specifications
Intro
AC operations
External AC adaptor/charger
NOTE: Adaptor will charge battery while unit is in use.
Wi-Fi
Battery type
LiON rechargeable
Battery life
3-10 hours, depending on use
Battery recharge time
3-4 hours
Maximum power usage
24 watts
Maximum heat
dissipation
9 watts
10/100
Table 6-3
Environmental requirements
System
Operating temperature
41 to 104°F (5 to 40°C)
Storage temperature
-4 to 158°F (-20 to 70°C)
Humidity tolerance
5 to 85% RH at +104°F (40°C)
Drop
IEC 60068, 68-2-32
IP/Video
6.2 Wi-Fi specifications
Table 6-4
Specs
6-2
Wi-Fi specifications
Protocol support
802.11b, with WEP security
Antenna
Detachable, hinged 3.25 in (8.3 cm) antenna
6: Specifications
Tech-X Flex™
Base Unit User Guide Issue 1
Co-location - This transmitter must not be co-located or operated in conjunction with any other
antenna or transmitter.
•
Compliance - This device complies with Part 15 of FCC rules. Operation is subject to the following
two conditions:
1 This device may not cause harmful interference and,
This device must accept any interference received, including interference that may cause
undesired operation.
Operation and installation - This equipment has been tested and found to comply with the limits for
a Class A digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in a commercial
environment. This equipment generates, uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the manufacturer documentation, may cause harmful
interference to radio communications. Operation of this equipment in a residential area is likely to
cause harmful interference in which case the user will be required to correct the interference at his
own expense.
•
Modifications - Changes or modifications not expressly approved by the party responsible for
compliance could void the user’s authority to operate the equipment.
Specs
IP/Video
•
Wi-Fi
•
10/100
RF exposure - This equipment complies with the FCC RF radiation exposure limits set forth for an
uncontrolled environment. This equipment should be installed and operated with a minimum distance
of 20 centimeters between the radiator and users and nearby persons.
System
•
Intro
6.3 FCC compliance statements
6: Specifications
6-3
Base Unit User Guide Issue 1
Tech-X Flex™
Intro
Wi-Fi
10/100
System
IP/Video
Specs
6-4
6: Specifications
Download: TECH-X-FLEX Hand-Held Tester User Manual Manual_Tech_X_Flex_Base_Issue1 Spirent Communications
Mirror Download [FCC.gov]TECH-X-FLEX Hand-Held Tester User Manual Manual_Tech_X_Flex_Base_Issue1 Spirent Communications
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Date Submitted2008-11-03 00:00:00
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Creation Date2008-10-02 14:01:46
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