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Most of the routing algorithms can be classified into one of the two following categories:
- Distance vector 
- Link-state 
Distance vector routing aims to determine the direction or vector and distance to other links in an internetwork. While the link-state aims to recreate the correct topology in an internetwork.

Classification of Routing Protocols

• Distance vector routing protocols 

Distance vector routing algorithm is periodically copying the routing table from router to router. Changes in the routing table is updated between routers that are interconnected in the event of topology changes. Distance vector algorithm is also called the Bellman-Ford algorithm.


Router B receives information from Router A. Router B adds distance vector numbers, such as the number of hops. This amount is added distance vector. Router B miss this new routing table to neighboring routers the other, the Router C. This process will continue for all routers.
These algorithms accumulate distance network so it can be used to improve the database of information about the network topology. However, distance vector algorithms do not allow the router to know for certain the internetwork topology since only see neighboring routers.
Each router that uses distance vector was first identified neighboring routers. Interface is connected directly to the router neighbors have distance 0. Routers that implement distance vector can determine the best path to get to the destination network based on information received from its neighbors. Router A study of other networks based on information received from the router B. Each of the other router adds in its routing table that has accumulated distance vector to see the extent to which network to be addressed. As described by the following picture:

distance vector network discovery

Routing table updates occur when there is a change toplogi network. Similar to the process of discovery, topology change update process step-by-step from router to router. Figure shows the distance vector algorithms call to all the routers to send the contents of its routing table. Routing table contains information about the total path cost determined by the metric and the logical address of the first router in the network that is in the contents of the routing table, sperti described by Figure below.

distance vector topology changes

routing metric components

Analogy distance vector can be described by the highway. Mark indicating the point to the destination and shows the distance to the destination. With signs like that rider to easily determine the approximate distance to be traveled to reach the goal. In this case the shortest distance is the best route.



In the next post I will discuss about the link-state. Thanks guys