Which of the following are the distance-vector routing protocols? Each correct answer represents

a complete solution. Choose all that apply.

A.
IS-IS

B.
OSPF

C.
IGRP

D.
RIP

Explanation:

Following are the two distance-vector routing protocols:
RIP: RIP is a dynamic routing protocol used in local and wide area networks. As such, it is
classified as an interior gateway protocol (IGP). It uses the distance-vector routing algorithm. It
employs the hop count as a routing metric. RIP prevents routing loops by implementing a limit on
the number of hops allowed in a path from the source to a destination. It implements the split
horizon, route poisoning, and hold-down mechanisms to prevent incorrect routing information from
being propagated.
IGRP: Interior Gateway Routing Protocol (IGRP) is a Cisco proprietary distance vector Interior
Gateway Protocol (IGP). It is used by Cisco routers to exchange routing data within an
autonomous system (AS). This is a classful routing protocol and does not support variable length
subnet masks (VLSM). IGRP supports multiple metrics for each route, including bandwidth, delay,
load, MTU, and reliability.
Answer options B and A are incorrect. OSPF and IS-IS are link state routing protocols.