What routing algorithm is used by RIP and IGRP?

Concept

Routing protocols can be classified by the information routers exchange and by how they compute paths. In distance-vector routing, a router advertises destination metrics to its neighbors and updates its table from neighbor information. In link-state routing, routers flood topology state and compute shortest paths locally.

Application

1. RIP is a distance-vector protocol: it exchanges destination-and-metric information with neighboring routers and uses the Bellman-Ford distance-vector method.

2. IGRP also uses distance-vector technology, although its metric combines bandwidth, delay, load, and reliability rather than using only RIP-style hop count.

3. The algorithm family common to both protocols is therefore distance vector.

Cross-check and contrast

The alternatives describe a different protocol, a different algorithm family, or a broader operating mode:

• OSPF is a protocol that uses the link-state approach.

• Link-state protocols flood topology information and compute shortest paths from a topology database.

• Dynamic routing is an umbrella mode that includes both distance-vector and link-state protocols.

Result: Distance vector.