Converged Services over MPLSAndrew G. Malis, TellabsThis article has discussed the development ofconverged network services over MPLS-basedbackbones. The popularity of this approach isevident in the marketplace: in 2005 alone,MPLS-based VPN services produced over US$4billion in revenue for service providers worldwide.Almost every major data networking serviceprovider has either deployed MPLS or is inthe process of deploying MPLS, and a numberhave publicly announced their plans to completelyconverge their services over MPLS networks.Some of the better known of these serviceproviders include AT&T, Bell Canada, Bell-South, Broadwing, BT, Cable & Wireless, ChinaTelecom, Deutsche Telecom, Equant, FranceTelecom, Infonet, NTT, Saavis, Sprint, TelecomItalia, Telstra, and Verizon.These and literally hundreds of other serviceproviders are using most, if not all, of the MPLSbasedmechanisms described in this article,including MPLS traffic engineering, layer 3VPNs to provide business IP services, and layer1 and 2 VPNs to provide converged TDM, framerelay, ATM, and Ethernet services. The fact thatMPLS is being used to provide these services isnot always readily apparent; for example, thetraffic engineering procedures in use by a serviceprovider are often not publicly disclosed forcompetitive reasons. In other cases, MPLS-basedservices have public brand names, such as IPEnabledFrame Relay or Metro Ethernet, thatdo not include MPLS in their name, even thoughthey use MPLS mechanisms to provide the services.For further investigation, a selection offreely available white papers on MPLS technologyand deployments can be found online at theMPLS Resource Center, http://www.mplsrc.com/.

Delay-Margin based Traffic Engineering forMPLS-DiffServ NetworksMohamed Ashour and Tho Le-NgocIn this paper, we presented a delay-margin based TE approachto provide end-to-end QoS in MPLS networks using DiffServ atthe link level. Three traffic engineering algorithms are developedusing a nonlinear formulation of the TE problem in the formof end-to-end delay margin. The algorithms provide more controldimensions of the network, while keeping the simple Diff-Serv service provisioning architecture. Simulations show thatthe end-to-end class adjustment and the weight adjustment algorithmscan be used separately to enhance the performance ofexisting routing techniques. In conjunction with the route configurationalgorithm, they further increase the network performance.Approximations were also proposed for a possible distributedtraffic engineering structure.

Demonstration of All-Photonic SpectralLabel-Switching for Optical MPLS NetworksReuven E. Gordon, Member, IEEE, and Lawrence R. Chen, Member, IEEE

We have demonstrated a simple, all-photonic LSS to switchweight four, spectral labels (concurrent quadruple wavelengthconversion) in an LSR of an optical MPLS network. The staticTF plots indicate that a noisy input label with small ER wouldbe switched to a clean, amplified, output label. Label-switchingand CR improvement was confirmed by the step response plots.For slowly modulated labels (as used in the step response), thiscorresponds to reamplification and reshaping (2R) regeneration.To negate label inversion arising from XGM in the LSS, onepossible simple modification could be made, as shown in theblock diagram of Fig. 4. In this setup, spectral label is inputto an XGM-based multiple-input to single-output wavelengthconverter. The output control wavelength is sent to an LSSmodified to accept a single input. By using a dedicated controlchannel in the intermediate step with sufficient power to saturateSOA , wavelength overlap (and thus, ER degradation) wouldnot occur in switching between label and label .To switch higher weight spectral labels, additional portscould be selected in the AWG, or several, simple LSSs couldoperate in parallel, where each unit converts a unique sectionof the label. Tunable label-switching should also be possible byusing tunable wavelength-selective components (for example,a wavelength-selective microoptoelectromechanical systemsswitch) in the SFRL.