TIA ANSI/TIA-921-A

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 combinations 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, reordering, or 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 Agents, Media Servers, Media Gateway Controllers, Gatekeepers, Application Servers, Routers, etc.)

o IP Video (IPTV, video conferencing, telepresence, etc.)

o IP Phones (including soft 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 (voiceband data, VBD) modem-over-IP gateways

o TIA-1001 (and V.151) textphone-over-IP gateways

The model includes parameters that can be used to configure and setup suitable emulator equipment.

This standard includes mandatory requirements, recommendations and options; 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, such as those experienced in Well-Managed (QoS-managed networks), Partially-Managed (Non-QoS) and Unmanaged (Internet) networks.

• Some VoIP 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 PSTN portion of the end-to-end connection.

• The network model represented in this standard does 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 manufacturers in the 2007 timeframe and will continue to evolve as more statistical information becomes available and as the IP network evolves.