OSPF 1 path !!

Unanswered Question
Feb 15th, 2008

Hi, in my network i want to make sure that every router has exactly 1 route to other routers LAN ( there are total of 100 routers in my network ), is there any way to do it ?


I have this problem too.
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royalblues Fri, 02/15/2008 - 23:54

We need more information about your network topology?

BTW is there any specific reason to have only one route? Static routing seems to be the best option if this is the case


illusion_rox Sat, 02/16/2008 - 00:15

hi Narayan, to answer your question i need to ask 1 thing more, Does Assymetric routing causes any harm ??? actually my administrator cannot allow assymetric routing which can possibly be a result of more then 1 routes in routing table, currently i have done ospf costing in such a way that only route is there at a time but still want to make sure that routing table NEVER has more then 1 route.

royalblues Sat, 02/16/2008 - 00:23

Answer would be yes/no..

Applications work well even with asymmetric routing unless there is a major chnage in path which causes latency/loss etc... (eg on the internet you can never expect the paths taken to be the same both ways :-)

Having one route in the RT depends again on your topology. Though you have made sure that OSPF choses only one path manipulating the cost, the same router may install multiple routes after a link fails/converges depending on its link state database


Richard Burts Sat, 02/16/2008 - 08:47


I am not sure that forcing only a single route in the routing table is necessarily an effective solution. Think about a situation with 2 routers (routerA and routerB) which have 2 paths between them. If routerA sets the metric to use link1 and if routerB sets the metric to use link2 then both routers will have only a single entry in the routing table but there will be assymetric routing.

Whether assymetric routing is a problem or not depends on several things. But in general assymetric routing within the interior of your routing domain is not much of a problem. Is there some reason that you believe that you need to prevent any assymetric routing?




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