scope:

This TR provides a practical way of assessing the availability of access to IP networks. The use of these measures is demonstrated through examples.

This methodology is seen as being highly useful because it complements the traditional methods for reliability assessments. While highly practical, this method is one of several possible methods that could be used for assessing IP network reliability, and is not intended to preclude the use of other methodologies.

This TR addresses only IP-based access networks (and not IP-based backbone networks). Other than total loss of service from equipment outages, it does not include consideration of defects (such as delay, packet loss, and jitter) that may prevent satisfactory delivery of service. Work is ongoing at Working Group T1A1.2 in these areas. This TR will be useful to the industry with the understanding that these issues still need to be addressed.

Purpose

This TR was developed in the interest of relating useful availability measures for access to IP-based networks. In particular, there is no widely accepted way of relating IP component failures to service outages as experienced by users of IP services. This TR is intended to provide initial guidance in this area, with the goal of stimulating greater industry collaboration on IP reliability issues. This TR is complementary to other T1A1 work on IP performance of networks and services.