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Stubby / Totally Stubby Default Routes vs ISP Default Routes


I understand that configuring a stubby or totally stubby area injects a default route for other areas or routes endorsed by an ASBR. I was worrying about the delay caused by extra hops in an area if only one router was to be the internet gateway. So, if I have multiple branches in an area, and if these branches rely on only one router for net access, does this mean, reducing processor cycles by using stubs has a cost in exchange of more hop counts? It seems that using a stubby / totally stubby configuration is not efficient as it seems for it causes the default routes per area to be pointed to the ABR who is the only one who can get out to the public net.

Can you suggest any best practices?

Thanks for reading this.



Stubby / Totally Stubby Default Routes vs ISP Default Routes

Hi Kevin,

That depends on where exactly you internet break-out router is...

For example, if you internet break-out router  is sommewhere in Area 0, then anyways you have to go all the way to Area 0 ( read though all branch relay ) for internet access.

However, if you have got Internet in one of the non area 0 ( zero) then you can configure that area as NSSA ( if you want that internet link to be used by other area's as well ). In this case, you non area zero branches will use that ASBR for internet break-out.

PS: If you can provide rough topology ( diagram ) of you network, this forum can suggest better solution.


Smitesh Kharecha

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