Lightpath-Level Protection versus Connection-Level Protection for Carrier-Grade Ethernet in a Mixed-Line-Rate Telecom Network

Abstract

Ethernet is a success story in Local Area Networks (LAN). Efforts for extending its boundaries beyond LAN to the carriers' backbone networks are in progress. We study the problem of designing reliable and cost-efficient high-rate (100 Gbit/s) carrier-grade Ethernet in a multi-line-rate telecom network under signal transmission-range constraints. Reliability is achieved using shared-path protection at two levels: (1) Protection-at-Connection (PAC) level, or (2) Protection-at-Lightpath (PAL) level. We study the two cases for their impact on network cost and other performance parameters. We construct a graph, called Mixed Topology (MT), using which it is possible to: (1) identify traffic grooming possibilities, (2) select a path which requires the minimum amount of 3R regeneration, and (3) effectively choose the data rate of a lightpath to be established. Our algorithms, tested on the 17-node German network, lead to the following findings: (1) for both PAL and PAC, our MT-based algorithm resulted in lower network cost and higher lightpath utilization compared with other schemes; and (2) in general, PAL incurs slightly higher cost than PAC.