Question

T7.
Prefix
An IP router implementing CIDR services a
packet with address 131.23.151.76. The routers
routing table has the following entries:
Output Interface identifier
131.16.0.0/12
131.28.0.0/14
131.19.0.0/16
131.22.0.0/15
The identifier of the output interface on which
this packet will be forwarded is
[Ans: (1)]
2
duced or utilised in any form without the written permis​

Answer 1

Explanation:

Longest Prefix Matching rule. The rule is to find the entry in table which has the longest prefix matching with incoming packet’s destination IP, and forward the packet to corresponding next hope.

In the above example, all packets in overlapping range (192.24.12.0 to 192.24.15.255) are forwarded to next hop B as B has longer prefix (22 bits).