Cisco Multiservice Switching Networks

This chapter concentrated on the configuration aspects of two applications of MPLSVPNs and QoS. MPLS overcomes the problem of overlapping IP address ranges by introducing the route descriptor field that unambiguously identifies a service provider's end customer routes within the MPLS core. With the address problem resolved, this chapter moved on to describe the per-switch configuration of multi-protocol iBGP, required to transport customer VPN routes and associated traffic across the core. Besides iBGP, an explanation of the eBGP configuration is required to pass the VPN customers' private routes to the provider's edge routers.

After the VPN configuration, a QoS example was offered. Frame-based MPLS's method of conveying DiffServ information to LSRs using a shim header was contrasted with the cell-based MPLS method using the label and CLP bit. CoS enables QoS, so this chapter finished with a discussion of how to enable multi-vc functionality to support up to four classes of service along a given path. In addition, the CLI syntax required to categorize incoming traffic into the proper CoS was given.