Chapter 7, Problem P14P

Explanation of Solution

Chaining used in direct routing:

As in the section 7.7.2, suppose the chaining is used in indirect routing via home agent, the following events would occur:

• The node “A” will get the mobile node then “A” alerts the home agent that the mobile node currently visiting “A”. The datagram to the mobile is forwarded to the particular COA (care-of-address).
• The mobile node is moved to the node “B”. The foreign agent at node “B” will alerts the foreign agent at node “A” and in node “A” the mobile node is no longer stayed, but in fact is resident in node “B” and that has the specified care-of-address in node “B”. Forward the datagrams by the foreign agent in node “A” and it receives that are addressed to the mobile care-of-address in node “A” to the mobile care-of-address in node “B”.
• The mobile node is moved to the node “C”. The foreign agent at node “C” will alerts the foreign agent at node “B” and in node “b” the mobile node is no longer stayed, but in fact is resident in node “C” and that has the specified care-of-address in node “C”. Forward the datagrams by the foreign agent in node “B” and it receives that are addressed to the mobile care-of-address in node “B” to the mobile care-of-address in node “C”.

If the mobile node returns to the home agent or it goes offline, the datagram forwarding state must be maintained by the foreign agents in “A”, “B” and “C” are removed.

Chaining not used in direct routing:

Suppose the chaining is not used in indirect routing via home agent, the following events would occur:

• The node “A” will get the mobile node then “A” alerts the home agent that the mobile node currently visiting “A”...