 a strict priority queue makes MPLS very attractive for companies wishing to use VoIP across their WANs. For companies with thousands of nodes, MPLS can have a significant impact, especially where Frame Relay might have been used previously. So how do you configure MPLS? In short, you don't. From a customer (versus a pro- vider) viewpoint, you don't need to configure anything to make MPLS work-it all happens on the provider's equipment. This is a sharp contrast to both Frame Relay and ATM, where there are all sorts of things to know and configure. For most implemen- tations of MPLS, you need to know BGP, and if you want to use QoS, you'll need to know how to configure that. Some providers that use BGP will allow you to use EIGRP instead of BGP, but I don't recommend this. Sure, it may be easier for you to understand if you have no experience with BGP, but you'll just be letting the provider do the BGP- EIGRP redistribution for you, and you'll lose control of how that's done. That might not be a big deal if you've got a simple MPLS environment, but with complex envi- ronments, redistribution can cause all sorts of problems if not properly managed. Here is a sample MPLS router configuration for the router at branch number 10 from the preceding example. First I'll design the QoS. We'll keep it simple. VoIP RTP and call control will get priority, and everything else will be dropped into the default queue. The priority queue can use up to 40 percent of the link, while call control will get 5 percent. See Chapters 31 and 32 for more detail on QoS: class-map match-any VoIP-RTP match ip dscp ef class-map match-any VoIP-Call-Control match ip dscp CS3 match ip dscp af31 policy-map MPLS-QoS class VoIP-RTP priority percent 40 class VoIP-Call-Control bandwidth percent 5 class class-default Fair-queue Here's the configuration for the MPLS link. Notice that there's nothing MPLS-specific in this configuration: interface Serial0/3/o description [ Branch 10 MPLS ] ip address 10.255.10.2 255.255.255.252 encapsulation ppp auto qos v