Abstract

Layer 3 switching is a subject vehemently discussed in the networking community. In addition to a number of manufacturer-specific approaches, Multi-Protocol Over ATM (MPOA) and Multiprotocol Label Switching (MPLS) are the most important examples of this technology. MPOA [1,2] was released in 1997 by the ATM Forum; MPLS [3,4] is a collection of IETF Internet drafts. This paper presents the concept of MPOA and reports on experiences resulting from the practical use of MPOA implementations from several manufacturers. The report also discusses the areas in which MPOA can be appropriately employed. Two years after the release of the MPOA standard, time has come to critically discuss the original objective of MPOA, to examine the implementations of several manufacturers and to compare MPOA with other solutions and their objectives. Keywords ATM, MPOA, MPLS, Switching, Routing 1 The concept of MPOA The objective of MPOA is the efficient transmission of unicast data between subnets in a L...