In this article we will discuss Distance Vector Technologies, will make brief discussion on Distance Vector Technologies, In last article we discuss about Achieving Convergence.
Distance vector routing protocols share updates between neighbors. Neighbors are routers that share a link and are configured to use the same routing protocol.
The router is only aware of the network addresses of its own interfaces and the remote network addresses it can reach through its neighbors. Routers using distance vector routing are not aware of the network topology.
Some distance vector routing protocols send periodic updates. For example, RIP sends a periodic update to all of its neighbors every 30 seconds. RIP does this even if the topology has not changed. RIPv1 sends these updates as broadcasts to the all-hosts IPv4 address of 255.255.255.255.
The broadcasting of periodic updates is inefficient because the updates consume bandwidth and network device CPU resources. Every network device has to process a broadcast message. Instead of using broadcasts like RIP, RIPv2 and EIGRP can use multicast addresses to reach only specific neighbor routers. EIGRP can also use a unicast message to reach one specific neighbor router. Additionally, EIGRP only sends updates when needed, instead of periodically.
The two modern IPv4 distance vector routing protocols are RIPv2 and EIGRP. RIPv1 and IGRP are listed only for historical accuracy.