path selection in ospf

Unanswered Question
May 4th, 2009
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if i have two wan routers connected to one switch....WAN router 1 shd be primary and wan router 2 shd be secondry....i have two vlans config on switch 20.0 and 30.0 for both the router lan (unfortunatly design is that both are on dif subnet) now my requirment is that if a packet comes to swicth it shd be routed to first router and if first router fails it shd route to second router.....and i have to use ospf we do it is it cost or metric and what are the commands......thanks guys

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Overall Rating: 5 (1 ratings)
guruprasadr Mon, 05/04/2009 - 21:18
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Assuming you Network as WAN Environment now,

WAN Router connected to Service Provider1 and Servier Provider2.

Last-mile is configured with OSPF as the Routing Protocol. The Remote prefixes are received via both the Service Providers cloud.

The Optimal way is to manipulate with the OSPF Cost from the CE WAN Router point.

Best Regards,

Guru Prasad R

The_guroo_2 Mon, 05/04/2009 - 22:14
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Thanks Guru

i am getting a default route from a same service provider so its connected to same service can we start from lan environment hjow i will config cost on switches keeping in mind that they are using vlan.....thanks

c.captari Mon, 05/04/2009 - 22:26
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Guroo ...this issues has been opened up yesterday

Some solutions were given to you but you dropped it in the air.

Anyway, if you are so stubborn in using different subnets on the lan side of wan routers here is what you need to do.


router ospf 1

default-information originate metric 100


router ospf 1

default-information originate metric 110

This way.. WAN_A will be the prefered one.

The_guroo_2 Tue, 05/05/2009 - 00:57
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Thanks for your kind reply.....and thanks for your help but dude just wanna add something i am not stuburn i have told you 5 times that , that is design requirment....and if u see my very first post i have already mentioned that if it was a same subnet that i would have gone for HSRP....but i guess you are not getting the point and keep insisting on somehting which i dont its not me who decides design and i have left withno choice but to ask for solution....and i guess i got it.....

c.captari Tue, 05/05/2009 - 02:44
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cheers then.glad it helped


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