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.

Heuristics for Sparse Traffic Grooming in Dynamic WDM Optical Mesh Networks

“…Several approaches based on network topology information like highest nodal degree for sparse node or G-node selection was proposed in [2]. Simple other heuristics like random and nodes with highest bypass traffic were chosen for grooming [2] and have been shown that optimal performance near to full grooming can be achieved using sparse grooming in the same network keeping the other resources like wavelengths etc. constant.…”

“…Most of the previous work done in full grooming network is assumed to have traffic grooming capabilities [1]. Research done in sparse grooming, attempts to find the locations of grooming sites [2] [10].…”

“…constant. Several of the approaches discussed here assumes two types of traffic request either static call arrival [2] [8] [10] or dynamic call arrival according to poison process with call holding time following exponential distribution [3] [4] [5]. In dynamic call arrival process each node in the network gets an equal chance of being a source and destination using uniform distribution, traffic or bandwidth request were also generated uniformly.…”

“…These are enriched with routing, grooming, and restoration at the wavelength level. In such an optical fiber there may be nearly 360 DWDM channels each of which is 100 Gbps [1] [2]. This provides a very huge bandwidth but the requirement of user is very less in this comparison.…”

“…Sparse grooming is an alternative in which, a selected subset of nodes are equipped with the grooming facilities and we call them G-nodes as in [2]. Research done in sparse grooming attempts to find the location of grooming sites which will provide performance as near to full grooming.…”