Why is AD of 5 for EIGRP Summary?

j4rt02

Why does EIGRP Summary route have preference, especially with the problem of auto-summary and discontinuous networks?

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Comments

atorven

Why it's AD is 5, you would have to ask the people who came up with those values, why it's preferred over others is because it's AD is lower than others. As for auto-summary, just disable it.

Monkerz

AD is a local preference. So EIGRP's summary route, within the router advertising it will be 5, but all other routers receiving that advertisement will be the normal 90 or whatever you have set the default distance to.

As to why such a low AD, you want your advertising router to use it's own summary route rather than the same summary being advertised by another router via any protocol. If your summary router doesn't have a more specific route, it will drop the packet rather than sending it in a loop.

j4rt02

Monkerz wrote: »

AD is a local preference. So EIGRP's summary route, within the router advertising it will be 5, but all other routers receiving that advertisement will be the normal 90 or whatever you have set the default distance to.

As to why such a low AD, you want your advertising router to use it's own summary route rather than the same summary being advertised by another router via any protocol. If your summary router doesn't have a more specific route, it will drop the packet rather than sending it in a loop.

I didn't realize that was only for internal summary routes. Makes sense.