of the core site routers fails, the traffic takes an alternate path from the legacy X.25 switch at
the functioning sites. In other words, if router Chicago fails, the switch at New York will still
be able to get to Livermore via router Annapolis.
There are many ways to configure QoS. A practical method in this example might be to
configure Class-Based Weighted Fair Queuing. CBWFQ is a good choice because when you
use extended access lists, the STUN traffic can be prioritized. You can also guarantee a certain
amount of bandwidth per STUN tunnel.