entary to DiffServ, IntServ's RSVP, and the ATM QoS architecture. Finally, it solves the n-squared route propa- gation problem in large backbones, where routers have to be interconnected with mesh of ATM or Frame Relay virtual circuits. Major efforts are under way to adapt the control plane of MPLS to direct the routing of not just LSRs but also an expanded universe of devices, including opti- cal switches and other optical elements. This will allow optical switches, optical cross-connects, LSRs, regular IP routers, and even time division multiplexers to Chapter 10 Next-Generation Networks recognize each other and exchange information. The same routing system can con- trol optical paths in the DWDM core, LSPs across the MPLS backbone, and paths involving any IP routers at the edge of the network. This is the realm of GMPLS, which is discussed in detail in Chapter 11. Whether with MPLS or GMPLS, service providers can simplify their operational procedures, deliver more versatile IP ser- vices, and, most importantly to customers, sign meaningful SLAs. Chapter Optical Networking The recent inventions and developments in optical networking will no doubt yield a new, radical perspective on communications. We are beginning to see some excit- ing applications being developed as a result of the bandwidth that we are unleash- ing. This chapter discusses end-to-end optical networking, the optical edge, the optical core (and the overlay and peer-to-peer networking models), the IP+optical control plane, and the migration to optical networking. Optical Networking Today and Tomorrow The performance improvements-in speed, cost, and capacity-of fiber have been fast and furious. The number of bits per second that fiber can carry doubles every 9 months for every dollar spent on the technology. The number of bits per second per lambda (a), or wavelength, doubles every 12 months. The cost of transmitting a bit of information optically drops by 50% every 9 months, and fiber prices, on a per-megabits-per-second basis, are falling by 60