Link State Vs Distance Vector

Comparison: Link State vs Distance Vector

See below diagram. If all routers were running a Distance Vector protocol, the path or 'route' chosen would be from A  B directly over the ISDN serial link, even though that link is about 10 times slower than the indirect route from A  C  D  B.

A Link State protocol would choose the A  C  D  B path because it's using a faster medium (100 Mb Ethernet). In this example, it would be better to run a Link State routing protocol, but if all the links in the network are the same speed, then a Distance Vector protocol is better.

 

LINK STATE  

Link State protocols track the status and connection type of each link and provides a calculated metric based on many factors, including some set by the network administrator. Link state protocols are aware whether a link is up or down and how fast it is and calculates a cost to 'get there'. Since routers run routing protocols to figure out how to get to a destination, you can think of the 'link states' as being the status of the interfaces on the router. Link State protocols will take a path which has more hops, but that uses a faster medium over a path using a slower medium with fewer hops.
Because of their awareness of media types and other factors, link state protocols require more CPU resources and memory. Distance vector algorithms being simple they don’t consume more CPU resources.