Summarization yes or no

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Dec 7th, 2008
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I redesign my network(which is about 30 routers and 60 switches) in order to be possible to configure summarization(specific IPs in specific places). I use EIGRP as my routing protocol . Does it worth it to configure summarization with that size of network? If yes manual or auto?

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royalblues Sun, 12/07/2008 - 09:42
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It would really depend on the way you have designed your IP schema.

Automatic summarization will only summarize at classful boundaries.

Manual summarization at the interfaces could reduce the number of entries in the routing table as well limit the eigrp query process


Edison Ortiz Sun, 12/07/2008 - 14:24
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As Narayan pointed out, summarization is a great technique for reducing the size of the routing table in your routers.

With that said, you must proceed with care when deploying summarization, specially with distance vector protocols such as EIGRP. EIGRP has the split-horizon rule automatically enabled and it won't receive a route that it already knows (loop avoidance).

If you were to summarize a couple of subnets and try to advertise the summary, the remote routers must have different summarized networks else the routes won't be received.





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