Link State and Distance vector??

Answered Question
Aug 20th, 2010

Hi,

Some One Ask me the 10 difference between Distance vector and Link State??

But I know only one or two pls help us to provide the details.

I have this problem too.
0 votes
Correct Answer by Peter Paluch about 4 years 11 months ago

Abhinay,

Well, you're correct, DV protocols use a distributed form of Bellman-Ford algorithm while the LS protocols use the Dijkstra algorithm.

Best regards,

Peter

Correct Answer by Peter Paluch about 4 years 11 months ago

Abhinay,

Well, while it is certainly possible to find 10 differences between LS and DV routing protocols, there is hardly any "common set of differences". I am not quite sure which differences was that person interested in.

Think of differences in the following areas:

  1. DV protocols make all their computing work and next hop selection depending exclusively on information provided by directly neighboring routers, and do not know the exact network topology. LS protocols first build a topological representation of the network (or a part of it) in each router's memory and each router - knowing the topology of the network - computes reachable networks and best paths to them.
  2. DV protocols are more prone to creating routing loops and can be slower in convergence. LS protocols are less susceptible to routing loops and can be somewhat faster in convergence.
  3. DV protocols tend to be less intensive on CPU and memory than LS protocols because they store and process significantly less information with less complexity.
  4. DV protocols usually (but not always!) send their updates in regular intervals, even if there is no topological change in the network. LS protocols initially flood the information throughout the network and then send updates only in case of topological changes.
  5. DV protocols generally allow you to summarize routing information at an arbitrary point in the network. LS protocols allow summarization only at selected routers that perform so-called inter-area routing.
  6. DV protocols can be described as flat - they do not divide the network into a backbone and other parts, or areas, that communicate over the backbone. A certain kind of hierarchy in DV can be implemented using judicious summarization. LS protocols understand by their design that there are certain levels of routing in a network (intra-area, inter-area, external) and divide the network into areas, imposing certain rules on how the routing information is transferred between areas.
  7. DV protocols generally use various techniques to avoid routing loops or to terminate them in a reasonable time (though only EIGRP is currently using an approach that guarantees a loop-free operation) - split horizon, poisoned reverse and/or route poisoning, counting to infinity. LS protocols do not use these approaches as they do not need them.
  8. DV protocols are generally easier to configure but they are limited when it comes to troubleshooting network problems. LS protocols can be initially more complex to configure and operate properly, but for a skilled administrator, they are a significant troubleshooting tool as well because from a single router, the map of the entire network can be extracted (by looking into the topological database) and thus, from a single place, the entire network can be seen and verified to a certain extent (links, addressing).
  9. DV protocols are unsuitable for applications where the precise network topology must be known. An example of such application is the MPLS Traffic Engineering that builds tunnels with guaranteed bandwidth. In order to know if there still is a path towards the destination with a particular free bandwidth, it is necessary to know about all links in the network, their maximum capacity and current reservations. Only LS protocols can be used in such case.
  10. DV and LS protocols differ in their names

Best regards,

Peter

Correct Answer by burleyman about 4 years 11 months ago

Are these homework questions.........

Well I am brushing up on this myself and I had a hard time getting ten but here are five....I think....anyone please correct me if I am wrong.

Distance-Vector updates only directly connected routers and Link-State updates every router in it's area.

Distance Vector sends update periodically and Link-State sends updates only when something has changed

Distance Vector send it whole routing table when it updates and Link-State only send the state of its Interfaces

Distance Vector can't "see" the network beyond its neighbors and Link-State "sees" the entire network (Area)

Distance Vector needs a way to prevent routing loops as it cannot see the entire network and Link-State sees everything and does not have routing loops.

Please remember to rate posts that help.

Mike

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Correct Answer
burleyman Fri, 08/20/2010 - 05:09

Are these homework questions.........

Well I am brushing up on this myself and I had a hard time getting ten but here are five....I think....anyone please correct me if I am wrong.

Distance-Vector updates only directly connected routers and Link-State updates every router in it's area.

Distance Vector sends update periodically and Link-State sends updates only when something has changed

Distance Vector send it whole routing table when it updates and Link-State only send the state of its Interfaces

Distance Vector can't "see" the network beyond its neighbors and Link-State "sees" the entire network (Area)

Distance Vector needs a way to prevent routing loops as it cannot see the entire network and Link-State sees everything and does not have routing loops.

Please remember to rate posts that help.

Mike

burleyman Fri, 08/20/2010 - 05:29

Came up with a few more and check this link out and look at the section about Link State vs Distance Vector

http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Routing-Basics.html#wp1020646

Distance Vector uses Hop count and Link State uses a shortest path to get to the destination

Distance Vector uses the Bellman-Ford Algorithm and Link State uses Dijkstra Algorithm

Distance Vector has a longer convergence and Link State's convergence is much quicker

Distance Vector uses less CPU and Memory and Link State is CPU and Memory intensive

Distance Vector is not that scalable and Link State is very scalable

Please remember to rate helpful posts.

Mike

Correct Answer
Peter Paluch Fri, 08/20/2010 - 05:34

Abhinay,

Well, while it is certainly possible to find 10 differences between LS and DV routing protocols, there is hardly any "common set of differences". I am not quite sure which differences was that person interested in.

Think of differences in the following areas:

  1. DV protocols make all their computing work and next hop selection depending exclusively on information provided by directly neighboring routers, and do not know the exact network topology. LS protocols first build a topological representation of the network (or a part of it) in each router's memory and each router - knowing the topology of the network - computes reachable networks and best paths to them.
  2. DV protocols are more prone to creating routing loops and can be slower in convergence. LS protocols are less susceptible to routing loops and can be somewhat faster in convergence.
  3. DV protocols tend to be less intensive on CPU and memory than LS protocols because they store and process significantly less information with less complexity.
  4. DV protocols usually (but not always!) send their updates in regular intervals, even if there is no topological change in the network. LS protocols initially flood the information throughout the network and then send updates only in case of topological changes.
  5. DV protocols generally allow you to summarize routing information at an arbitrary point in the network. LS protocols allow summarization only at selected routers that perform so-called inter-area routing.
  6. DV protocols can be described as flat - they do not divide the network into a backbone and other parts, or areas, that communicate over the backbone. A certain kind of hierarchy in DV can be implemented using judicious summarization. LS protocols understand by their design that there are certain levels of routing in a network (intra-area, inter-area, external) and divide the network into areas, imposing certain rules on how the routing information is transferred between areas.
  7. DV protocols generally use various techniques to avoid routing loops or to terminate them in a reasonable time (though only EIGRP is currently using an approach that guarantees a loop-free operation) - split horizon, poisoned reverse and/or route poisoning, counting to infinity. LS protocols do not use these approaches as they do not need them.
  8. DV protocols are generally easier to configure but they are limited when it comes to troubleshooting network problems. LS protocols can be initially more complex to configure and operate properly, but for a skilled administrator, they are a significant troubleshooting tool as well because from a single router, the map of the entire network can be extracted (by looking into the topological database) and thus, from a single place, the entire network can be seen and verified to a certain extent (links, addressing).
  9. DV protocols are unsuitable for applications where the precise network topology must be known. An example of such application is the MPLS Traffic Engineering that builds tunnels with guaranteed bandwidth. In order to know if there still is a path towards the destination with a particular free bandwidth, it is necessary to know about all links in the network, their maximum capacity and current reservations. Only LS protocols can be used in such case.
  10. DV and LS protocols differ in their names

Best regards,

Peter

burleyman Fri, 08/20/2010 - 05:46

Wow Peter great information thanks for sharing +5 for that!!

.

Thanks,

Mike

abhi-adte Fri, 08/20/2010 - 05:55

Distance Vector uses the Dijkstra's Algorithm and Link State uses Bellman-Ford Algorithm

Thanks for reply but I have doubt in this...

Correct Answer
Peter Paluch Fri, 08/20/2010 - 06:09

Abhinay,

Well, you're correct, DV protocols use a distributed form of Bellman-Ford algorithm while the LS protocols use the Dijkstra algorithm.

Best regards,

Peter

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