Shared Risk Resource Group
Shared risk resource group (commonly referred to as shared risk group or SRG) is a concept in optical mesh network routing that different networks may suffer from a common failure if they share a common risk or a common SRG. SRG is not limited to Optical mesh networks: SRGs are also used in MPLS, IP networks, and synchronous optical networks. An SRG failure makes multiple circuits go down because of the failure of a common resource those networks share. There are three main shared risk groups: * Shared risk link group (SRLG) * Shared risk node group (SRNG) * Shared risk equipment group (SREG). Failure recovery is a crucial in all types of networks. The MPLS as well as the IP network uses the high speed capabilities of modern optical networks. SRLGs typically deal with links between fiber optic nodes, but that is not always the case. SRLG can also be modeled if the links contain transmission lines instead of fiber optic cable. SRG modeling is also used when a provider generates a service-level agreement with a client with various protection schemes. (Wikipedia).
