Dissimilarity in routing protocols is not the only challenge a network administrator may face. Routed protocols, too, may be problematic. Ideally, an organization selects a single routed protocol such as IP or IPX and implements it broadly. Nevertheless, many of the same circumstances that could result in dissimilar routing protocols can also affect routed protocols. The end result could be multiple dissimilar routed protocols being used in different domains of an internetwork.
There are several options for coping with this incompatibility:
Supporting redundant routed protocols
Using protocol conversion gateways
Tunneling through incompatible network regions
Today's computers, and their ...