Description

Network recovery is critical capability that service providers must provide. It can be accomplished in four ways. Span, or local, protection is the most common recovery method. Another common method is path restoration which is accomplished end-to-end. Some service providers apply both span protection and path restoration in different parts of their networks in a "hybrid" configuration. Another more recent alternative is a feature in Multiprotocol Label Switching (MPLS) called "Fast Reroute." This praxis addresses several fundamental problems related to each of the above network recovery options in large service provider networks. First, the effects of the numbers of links, demand unit sizes, and link size modularity have on the four recovery methods, individually and collectively, are examined. Next, the selection of the minimum cost recovery method given the presence and levels of the other options is determined. Finally, the cost differences of the recovery methods given any combination of the other options and their levels are presented.