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.
4 comments:
hi uttam
the working terminology of dvp and lsp is different
path selection generally depends on the metric used by the protocol
if we consider igrp i.e. outdated will select the path with higher bandwidth though it is dvp
hope you got my point
with regards
Abdul Rahim Shaikh
Yes, you are right that metric is responsible to select the path, Here I am comparing RIP as DVP and OSPF as LSP. Since IGRP is outdated.Its correct IGRP is having metric Bandwidth and delay. But then also its a distance vector protocol, Since it belongs from DVP category. It has to mathematically compare routes using some measurement of distance. This measurement is known as the distance vector.
Routers using a distance vector protocol must send all or a portion of their routing table in a routing-update message at regular intervals to each of their neighboring routers.
For more info :
http://www.cisco.com/en/US/docs/internetworking/technology/handbook/IGRP.html
Yes the above statement you said are true but we had discussion on path selection of dvp not routing updates
Yes, Every routing protocol choose path based on metric but the way it works in background depends on category (DVP and LSP) in which it falls.I don't think now IGRP is newly used/implemented protocol in industry or in any exams, So in this post we compared RIP as DVP and LSP as OSPF.Since these are well known accepted protocol. Which are newly and currently used/implemented.
This post is for basic understanding for new learner.So its under basic tab.
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