Chapter 6 – Multilayer Networks

Publisher Summary This chapter discusses the recovery mechanisms and the strategies used for multilayer networks. It reviews some examples and case studies of recovery in such networks. These include the optical restoration and the MPLS traffic engineering (TE) fast reroute (FRR), the Synchronous Optical NETwork (SONET)/Synchronous Digital Hierarchy (SDH) protection and Internet protocol (IP) routing, the MPLS TE Fast Reroute and the IP routing. It describes three categories for providing the recovery in multilayer networks—the single-layer recovery schemes in multilayer networks, the static multilayer recovery schemes, and the dynamic multilayer recovery strategies. The labels in regular MPLS are represented as integers attached to an IP packet. The concept of the generalized MPLS (G-MPLS) allows a label to be represented as an integer, a time slot in a time division multiplexing (TDM) frame, a wavelength or waveband on a fiber, or as a fiber in a cable. The generalized label request consists of a label switch path (LSP) encoding type, a switching type, and a generalized payload identifier (G-PID). The encoding of the generalized label object depends on the link on which the label is used.