Analysis and design of AT&T's global PNNI network

Abstract

This paper presents work done in the development and operation of the layer 2 infrastructure in AT&T's global network, one of the largest in size and geographic coverage. While conforming to ATM forum's private network-network interface (PNNI) standard, additional features were built in to ensure low latency, among other network objectives. The network uses preferred routing, connection mastership, and delay-based administrative-weights for optimal path selection. Peer-group splits are utilized to deal with network growth. Overbooking rules are used for capacity management to improve efficiency. Extensive modeling and analysis of the network was performed to validate these design features. Some of the techniques described herein would also be applicable to other technologies such as OSPF and MPLS.