Distance vector algorithm and link state algorithm for Network layer routing algorithm

1.The distance vector routing algorithm (Distance vector ROUTING,DV) is the first routing algorithm used on the ARPANET network, also known as Bellman-ford routing algorithm and Ford-fulkerson algorithm, mainly in RIP (route Information Protocol) protocol. Cisco's IGRP and EIGRP routing protocols are also using DV as a routing algorithm.
The basic idea of "distance vector routing algorithm" is as follows: Each router maintains a distance vector (usually a delay is a variable) table, and then through the distance vector between neighboring routers to advertise the distance vector table updates. Each distance vector table entry consists of two parts: the best output line to reach the destination node, and the time or distance to reach the destination node, and each of the other routers in the communication subnet occupies a table entry in the table and is indexed as the table entry.every once in a while, the router sends it to all neighbor nodes to the distance table for each destination node, and it also receives the distance table for each neighbor knot dots. This and so on, after a period of time can be the network of routers to obtain the distance vector information on each router unified up, so that each router only need to view the distance vector table can be a different source grouping to find an optimal route.
2.Link state routing protocol is the most widely used intra-domain routing protocol. It uses a "puzzle" design strategy,that is, each router broadcasts its link state to its neighbors to other routers across the network。 In this way, when a router receives routing information sent from other routers in the network, it will assemble these link states and eventually generate a full-network topology view, which can be used to calculate the shortest path to other routers by the shortest path algorithm. Routers that run the link-State routing protocol, each router is sent the changed state to all other routers when the state of its interface changes, and each router uses the information it receives to recalculate the best path to each network, and then stores that information in its own routing table.

The idea behind the link-state routing algorithm is very simple and can be described in 5 basic steps.

1. Find his adjacency point and know the address of its network.

2. Measure the delay or overhead of each adjacency point.

3. Construct a grouping that contains all the information he has just received.

4. Send this packet to other routers.

5, calculate the shortest path to each other router. For example, each router runs the Dijkstra algorithm to find the shortest path from it to every other router.

Distance vector algorithm and link state algorithm for Network layer routing algorithm