tion of one vendor: Cisco GMPLS (discussed in Chapter 8) is an extension of MPLS, which has been around for about five years and is applicable at the UNI and NNI. In Chapter 2 this architecture, the MPLS control plane (for example, adaptations of RSVP traffic engineering [RSVP-TE] and constraint-based routing LDP [CR-LPD]) is implemented in each OXC or optical switch. The constrained- based routing mechanism and the signaling mechanism provide the control plane functionality of the OXC or optical switch. Wavelength lambda and switch ports are equated to labels; OXCs are equated to label-switched routers (LSRs) and lightpaths are equated to label-switched paths (LSPs). End Notes 1. Although we use the term "light," this signal is in the infrared domain; hence, it is invisible to the eye. 2. Two beams are needed for duplex communication. 3. Corning introduced SMF-28 fiber, the world's most extensively deployed fiber, in 1986. 4. John George, "Optical Architectures and Fibers," IEEE EFM Meeting, Hilton Head N.C., March 12-15,2001, Lucent Technologies. 5. K.M Feng et al., PTL (1999), and T. Day, "Widely Tunable Lasers- Tacking the Challenges of Today's Networks," www.newfocus.com. 6. Randy Bird, "Fiber Optics 101: A Primer," http://certcities.com/editorial/features/story.asp?EditorialsID=2 7. S2 is keyed to the S character. The meaning of S2 is different for every S. 8. For example, there are technical factors limiting transmission of 10 Gbps on a multimode fiber to around 82 m; new optimized multimode fibers are needed to reach (certain standards-driven goals of) 300 m. 9. Macrobending consists of loops that are much larger than the core, such as 1 inch in diameter; microbending consists of deflections of the fiber axis that are small compared to the core such as 2 nm. 10. Bellcore, Telecommunications Transmission Engineering, ISBN 1- 878108-04-2, 1990. 11. T. Day, "Widely Tunable Lasers-Tackling the Challenges of Today's Networks," NGN 2001 Proceedings, 2001; L. A. Coldren and S. W. Corzine, "Distributed Bragg Refl