1、 TIA STANDARD Network Model for Evaluating Multimedia Transmission Performance Over Internet Protocol TIA-921 June 2006 TELECOMMUNICATIONS INDUSTRY ASSOCIATION Representing the telecommunications industry in association with the Electronic Industries Alliance ANSI/TIA-921 Approved: 5/24/06 Copyright
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18、Network Model for Evaluating Multimedia Transmission Performance Over Internet Protocol Contents 1 INTRODUCTION1 2 SCOPE.2 3 INFORMATIVE REFERENCES .4 4 DEFINITIONS and Acronyms.5 4.1 Definitions5 4.2 Acronyms.7 5 DESCRIPTION OF MODEL.8 6 IP IMPAIRMENT LEVEL REQUIREMENTS9 6.1 Service Test Profiles.9
19、 6.2 Network Impairment Requirements.11 6.3 Test Setup12 6.4 Impairment Combination Tables .12 6.5 Network Model Coverage .17 Annex A (Informative) Rationale for IP Network Model23 A.1 Wireless LANS.23 A.2 Structured Wiring23 A.3 Hubs Versus Switches23 A.4 Access Rates.23 A.5 Router Delays 24 A.6 Im
20、pairment Data From Anonymous IP Network Service Providers .24 Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA-921 ii Annex B (Informative) Packet Delay and Loss Algorithms.2
21、5 B.1 General IP Network Model25 B.2 Packet Loss Model25 B.2.1 Bursty Packet Loss25 B.2.2 Consecutive Packet Loss26 B.3 Delay Variation Model.26 B.3.1 LAN and Access Link Jitter 26 B.3.2 Core Network Jitter26 B.3.3 Core Network Base Delay and Route Flapping.27 B.4 Core Packet Reordering .27 B.5 Mode
22、l Output .27 B.6 Model Input Parameters .27 B.6.1 Local and Remote LAN Segment Parameters.27 B.6.2 Local and Remote Access Link Segment Parameters .28 B.6.3 Core IP Network Segment Parameters 28 Annex C (Informative) Example Result Statistics.29 Copyright Telecommunications Industry Association Prov
23、ided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA-921 iii FOREWORD ANSI-accredited committee TR-30.3 has developed this standard, which defines a IP network model. This model, along with the specified scenarios, are intended for
24、evaluating and comparing communications equipment connected over a converged network. Building upon the experience of creating Network Models, TR-30.3 Subcommittee has created this Network Model for IP Impairments using the similar methodology developed in its previous standards and bulletins: TIA/E
25、IA 496A-1989: Interface Between Data Circuit Terminating Equipment (DCE) and the Public Switched Telephone Network, which includes a Network Model for Evaluating Modem Performance TIA/EIA TSB 37A-1994: Telephone Network Transmission Model for Evaluating Analog Modem Performance, which became ITU-T R
26、ecommendation V.56bis-1995 EIA/TIA TSB 38-1994: Test Procedures for Evaluation of 2-Wire 4 Kilohertz Voice Band Duplex Modems, which became ITU-T Recommendation V.56ter-1996 ANSI/TIA/EIA 3700-1999: Telephone Network Transmission Model for Evaluating Analog Modem Performance ANSI/TIA/EIA 793 -2000: N
27、orth American Telephone Network Transmission Model for Evaluating Analog Client and Digitally Connected Server Modems ANSI/TIA 876 2002: North American Network Access Transmission Model for Evaluating xDSL Modem Performance Copyright Telecommunications Industry Association Provided by IHS under lice
28、nse with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA-921 iv Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA-921 1 1 INTRODUCTIO
29、N Previous network transmission model standards and bulletins for evaluating modem performance (e.g. TSB-37A, TIA/EIA 3700, TIA/EIA 793 and TIA 876) have been statistical models in which likelihood of occurrence (LOO) values were assigned to all network elements and impairments. Test results using t
30、hese statistical models were expressed in terms of Network Model Coverage (NMC). These NMC results were unconditional not dependent on the a priori specification of any network elements or impairments. This is an example of a Statistical Model. Testing to a comprehensive Statistical Model suggests h
31、ow communications devices may perform over an IP network in terms of Network Model Coverage. Unlike the previous models, which focused on physical-layer impairments, this standard focuses on the impact of impairments on Layer 3 performance. IP streams from any type of network device can be evaluated
32、 using this model. Emphasis is given to the fact that manufacturers of communications equipment and service providers are interested in a specification that accurately models the IP network characteristics that determine performance. Evaluators desire a definitive set of simple tests that properly m
33、easure the performance of communications devices from various manufacturers. Therefore, the objective of this standard is to define a technology-independent model that is representative of the IP network, that can be simulated at reasonable complexity and that facilitates practical evaluation times.
34、 The IP network model presented herein represents a snapshot of actual network data provided by anonymous IP service providers and IP network equipment manufacturers in the 2005 timeframe and will continue to evolve as more statistical information becomes available and as the IP network evolves. In
35、developing this model, certain assumptions have been made based on the best available statistical information. These assumptions are given in Annex A: Rationale for IP Network Model. The model described in this document is technology independent and accommodates various IP communications networks an
36、d devices. The following are parameters and impairments that affect quality of service and IP network performance: Network Architecture Types of Access Links QoS-controlled Edge Routing Coding algorithms A/D and D/A Conversion MTU Size Signaling protocol mismatches Network faults Link Failure Time D
37、rift Route Flapping Reordered packets Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA-921 2 Packet Loss (Frame Loss) One-way delay (latency) Variable Delays (Jitter) Backgro
38、und Traffic (Congestion, Bandwidth, Utilization, Network Load, Load Sharing) 2 SCOPE This standard specifies an IP network model and scenarios for evaluating and comparing communications equipment connected over a converged wide-area network. The IP network model consists of many impairment combinat
39、ions that are scenario based and time varying. IP streams from any type of network device can be evaluated using this model. The test scenarios combine LAN, access, and core network elements in a realistic way to create Layer 3 IP network impairments that cause packets to experience varying delay or
40、 loss. These scenarios are based on actual network data provided by anonymous IP service providers and IP network equipment manufacturers. Examples of the types of equipment that can be evaluated using this model include: IP-connected endpoints: o IP Network Devices (such as: User Agents, Call Agent
41、s, Media Servers, Media Gateway Controllers, Gatekeepers, Application Servers, Edge Routers, etc.) o IP Video o IP Phones o IAF (Internet Aware Fax) PSTN-connected devices through IP gateways: o POTS through Voice-over-IP (VoIP) gateways o T.38 facsimile devices and gateways o V.150.1 and V.152 (voi
42、ceband data, VBD) modem-over-IP gateways o TIA-1001 (and V.151) textphone-over-IP gateways Figure 1 illustrates these devices and their interconnection through an IP network. Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or netw
43、orking permitted without license from IHS-,-,-TIA-921 3 Figure 1: Network Model for Evaluating Multimedia Transmission Performance The models include parameters that can be used to configure and setup suitable emulator equipment. This standard includes mandatory requirements, recommendations and opt
44、ions; these are designated by the words “shall,” “should,” and “may,” respectively. Limitations of this model: This IP Network Model is not intended to represent any specific IP network. Rather it provides a range of test scenarios that could represent a wide range of IP network characteristics, suc
45、h as those experienced in Well-Managed (QOS-managed networks), Partially-Managed (Non-QOS) and Unmanaged (Internet) networks. Some networks may utilize PSTN at one or both ends of the connection through a media gateway. This model only addresses the IP portion of the network and does not address the
46、 PSTN portion of the end-to-end connection. The network models represented in this standard do not model all possible connections that can be encountered between devices. The IP network model presented herein is based on an informal survey of anonymous IP service providers and IP network equipment m
47、anufacturers in the 2005 timeframe and will continue to evolve as more statistical information becomes available and as the IP network evolves. Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without licens
48、e from IHS-,-,-TIA-921 4 3 INFORMATIVE REFERENCES At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the standards published by them. ETSI TIPHON TR 101 329 - Part 2, Quality of Service (QoS) Classes IEEE 802.11A-1999, Information Technology Telecommunications and Information Exchange Between Systems LAN/MAN IEEE 802.11B/COR 1-2001, Wireless LAN MA
