Basic Single-Area IS-IS w/ VoIP

Essentially the same configuration as the basic IS-IS one with two VoIP routers added on either end.  These routers and the ones they attach to run OSPF with redistribution from OSPF into IS-IS.  The IS-IS border routers also have default routes and run "default-information originate" under the OSPF process so that the VoIP sessions can enter the IS-IS backbone.  The VoIP configuration is similar to that shown in the Multi-Area configuration.