Question

Computer Communication Networks

16. In a mobile routing environment, what is the major setback comparing an indirect to a direct routing architecture? (4 Points)

Answer 1

In a mobile routing environment, the major setback comparing an indirect to a direct routing architecture is:
The indirect routing to a mobile node approach goes through the problem of an inefficiency called the triangle routing problem. In this triangle routing problem, even when an efficient route exists between a correspondent and a mobile node, datagrams addressed to the mobile node are routed first to the home agent and later to the foreign network. This problem becomes the worst when, say, a mobile user visiting the foreign network of his friend or colleague and they both sit together side-by-side exchanging data over the network. Now, the datagrams from the correspondent i.e., the colleague or the friend are routed to the mobile user's home agent and later back again to the foreign network.

However, direct routing to a mobile node does not work this way. Direct routing eradicates this triangle routing inefficiency, however, it requires additional complexity. In this direct routing to a mobile node approach, a correspondent agent in the correspondent's network first figures out and understands the Care-Of-Address (COA) of the mobile node. The correspondent agent later tunnels datagrams directly to the mobile node's COA in a way, analogous to the tunneling the home agent performed.