Question
Consider a datagram network using 32-bit host addresses. Suppose a router has four links, numbered 0 through 3, and packets are to be forwarded to the link interfaces as follows:
a. Provide a forwarding table that has five entries, uses longest prefix match- ing, and forwards packets to the correct link interfaces.
b. Describe how your forwarding table determines the appropriate link inter- face for datagrams with destination addresses:
Answer
a)
Prefix Match Link Interface
11100000 0
11100001 00000000 1
11100001 2
otherwise 3
b) Prefix match for first address is 4th entry: link interface 3
Prefix match for second address is 2nd entry: link interface 1
Prefix match for first address is 3rd entry: link interface 2