Summary

This chapter looked at two different network designs and discussed how to arrive at complete working solutions. Each case started with an alternative VPN technologyL2TP in the first case and VLANs in the secondand migrated to MPLS VPN.

The move for Etiolles Networks was quite beneficial. Not only was it able to sell a new managed service, but its multicast and QoS operation also improved considerably. For Rengstorff Networks, the case for using MPLS VPN as a solution for open access was pretty clear. It was much less obvious that there would be any comprehensive reason to migrate its entire access network, though.

This chapter also tried to make the case that you can have too much of a good thing: Some of the gains you realize by opting for an MPLS-based solution may be outweighed by operational complexity if you greatly increase the number of PEs, such as by pushing MPLS to the furthest edge of the network. There may be cases in which this is the right thing to do, but you should look at all the details before making a decision.

Because the implementation-related details of the design issues have already been covered in prior chapters, this chapter did not go into all the details, but instead provided references where appropriate.