scope:

SCOPE & PURPOSE

Service availability has received strong attention in ATIS PRQC in terms of metric definitions as well as measurement methodologies. This Technical Report (TR) addresses the issue of multi-layer coordination in All-IP networks. The term "All-IP" is a broad term to describe some key architectural evolutions in telecommunication core and access networks that are being deployed. The general idea behind it is that one network transports all information and services (voice, data, and all sorts of media such as video) by encapsulating these into packets, like it is on the Internet.

The move to All-IP is a recognized technology trend in telecommunication networks. Many operators have finished the transition from traditional networks to All-IP networks or are on the way. However, All-IP networks also introduce new challenges in the area of reliability and security.

Given an All-IP network, there are many fault detection and localization mechanisms deployed on different network layers. However, the consideration of coordination among network layers is generally lacking in early network design. This leads to challenges in network-level fault diagnosis. Additionally, a promised benefit of the new technology is standardization, implying that the All-IP networks will be multi-vendor networks. This fact creates an additional challenge for multi-layer network coordination because the failure modes and recovery strategies of one vendor are unlikely to be made transparent to a competitor. New work was also initiated in ITU-T Study Group 12 Question 17 on guidelines for common IP/MPLS/Ethernet service classes to support interconnection between providers.

Specifically, this TR discusses multi-layer coordination for All-IP networks. Multi-layer coordination is essential for failure detection and correction. It discusses a methodology that has been employed to address multi-layer coordination challenges in large service-provider networks. This methodology applies the failure mode and effects analysis (FMEA) concepts to networks [Xian-2010].