EIGRP Default Route in production/lab networks

siggnation

I'm progressing through the ROUTE Simplified book and arrived at EIGRP default routes. I was curious, for anyone working with EIGRP mainly in a production network, what would be the best way to advertise a default route to perhaps a stub router? It looks like advertising a static route of 0.0.0.0 0.0.0.0 on the Hub router would work, but i know a summary-address would yield a lower AD. AD is locally significant to the router, so would this even matter?

Thanks!

EdTheLad

The summary-address would not yield a lower AD. There are 2 ways to advertise a default route 1) via redistributed static or 2) summary statement.
"ip default-network" is typically used for any other network than the default, but it's broken in current ios, so i'd forget about it.

Via option 1, you config a static pointing to NH interface, by default AD = 1, redistribute static in eigrp
Via option 2, you config an eigrp summary 0.0.0.0/0 which has an AD = 5

Option 1 will advertise a default and every other eligible eigrp prefix.
Option 2 will only advertise a default. You would config a leak-map to leak more specific prefixes

Choosing one over the other comes down to requirements, if the remote router was a stub and will always be a stub i would choose option 2. I'm not sure why your even thinking about AD here.

siggnation

EdTheLad wrote: »

The summary-address would not yield a lower AD. There are 2 ways to advertise a default route 1) via redistributed static or 2) summary statement.
"ip default-network" is typically used for any other network than the default, but it's broken in current ios, so i'd forget about it.

Via option 1, you config a static pointing to NH interface, by default AD = 1, redistribute static in eigrp
Via option 2, you config an eigrp summary 0.0.0.0/0 which has an AD = 5

Option 1 will advertise a default and every other eligible eigrp prefix.
Option 2 will only advertise a default. You would config a leak-map to leak more specific prefixes

Choosing one over the other comes down to requirements, if the remote router was a stub and will always be a stub i would choose option 2. I'm not sure why your even thinking about AD here.

Thanks Ed! You clarified this well for me. I'm largely unfamiliar with redistribution at the moment, as this topic shows up later in the book.

Cheers.