MPLS-Enabled Applications: Emerging Developments and New Technologies

15.3. INTERACTION WITH CLIENT EDGE EQUIPMENT

In earlier chapters, we discussed the admission control of LSPs into the network. It is anticipated that a further level of admission control will be required for some traffic types: admission control of client connections into LSPs by the ingress PE. As discussed in the DiffServ TE chapter of this book (Chapter 4), some implementations already have the ability to manually configure parameters such as the bandwidth requirement of a pseudowire on the ingress PE. The ingress PE then performs admission control of the pseudowire on to an LSP that goes to the appropriate egress PE. The natural next step is for the client edge equipment to signal its bandwidth and other connection requirements to the ingress PE, to avoid manual configuration on the PE. Schemes have been discussed in the MPLS and Frame Relay Alliance,^[] in the context of signaling interworking between ATM switches and MPLS PE routers [MPLS-ALL]. In this scheme, the ATM switch aggregates multiple VCs and VPs that need to pass to the same remote ATM switch into a single connection. The ATM switch signals to its local PE router the bandwidth requirements for that connection, which the PE translates into bandwidth requirements for a corresponding pseudowire to the egress PE. This is illustrated in Figure 15.2, in which an ATM switch, SW1, requires a trunk to SW3. It signals the bandwidth requirements of the connection to the attached PE router, PE1. PE1 performs admission control ...