Cost of loop-free alternates in IP-over-WDM networks

• Published in: Journal of optical communications and networking Vol. 7; no. 4; pp. 368 - 379
• Main Authors: Rozic, Ciril, Sasaki, Galen
• Format: Journal Article
• Language: English
• Published: Piscataway Optica Publishing Group 01-04-2015; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithm design and analysis; Computer networks; IP (Internet Protocol); IP fast reroute; IP networks; Loop-free alternates; Network design; Network survivability; Network switching; Network topologies; Network topology; Networks; Ports (Computers); Priorities; Protection switching; Routing (telecommunications); Switching theory; Topology; Traffic engineering; Traffic flow
• ISSN: 1943-0620; 1943-0639
• DOI: 10.1364/JOCN.7.000368

In Internet protocol (IP) networks, the failure recovery time of IP restoration, of several hundreds of milliseconds or up to seconds, is sufficient for most applications. But protection switching is needed for services that require very short recovery times of at most 50 ms. Loop-free alternates (LFAs) is a protection switching mechanism that is in the IP layer. We consider IP-over-WDM (wavelength division multiplexed) networks where IP routing eventually restores all traffic, while LFAs protect the fraction of the traffic that has high priority. Simulations show that if 50% of the traffic has high priority, then the additional cost to protect the high-priority traffic using LFAs is just a percent on average, under a particular cost model. Thus, with very little additional network cost, LFAs can guarantee that a large fraction of traffic will be protected between all source-destination pairs. In addition, a network design algorithm is presented that, given a traffic matrix and a physical network topology, will find a low-cost network design that includes determining the IP network topology, IP-link capacities, lightpath routing, and LFAs.