OSPF BACKUP LINK CONNECTING AREAS 1 AND 2, should be a virtual link?

[Louey]

Hi all,

I am designing a network routing with OSPF and i need a high availibility network.

I have three areas as you can see in the picture attached, area 0, 1 and 2.

Both Areas 1 and 2 are connected to backbone, but i want to create backup link between area 1 and 2 if primary links fail.

My question : should this link be configured as a virtual link or normal link ?

Thank you in advance

Louey

[rais]

Cisco 2811 is a single point of failure in this network. That core router fails, backbone area fails.

If the virtual link is configured as backbone, it would be a non-contiguous backbone.

You may just use static routes for the two routers with AD higher than OSPF. You might as well just put all routers in a single area.

HTH.

[Louey]

Hello,

Thank's for your reply.

It's a very simplified network i just built to ask the question here. Reals
routers are not 2811 and they are redundant in reality.

I just want to know how to configure the link named 'backup' in the image??

Should that be a virtual link?

Sorry i didn't understand your solution about static route, what is AD?
Can i just configure it as virtual link? The cost of backup route will be
automatically more than primary route.


Thank you
Louey

[paul driver]

Hello 

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@Louey wrote:

i want to create backup link between area 1 and 2 if primary links fail.

My question : should this link be configured as a virtual link or normal link ?

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I would say neither, have the routers run a different routing protocol such as eigrp but with an higher admin distance metric so if the primary links fails then this secondary eigrp backup path would be preferred between those two rtrs, but looking at your topology those rtrs that dont have a link to each other in each area would need to be connected to the backup rtrs also otherwise they would be isolated when the core fails.

Example:

router eigrp xxx
distance eigrp 111 170
neighbor x.x.x.x 0.0.0.0
network x.x.x.x