ip summary-address with AD

[dialerstring]

What are the benefits of having a summary address with an AD of 100 when using EIGRP? The AD is 5 by default.

Example

int di0
ip summary-address eigrp 100 10.100.33.16 255.255.255.240 100

Thanks.

 

[burtsbees]

The default for EIGRP is 90 (internally) and 170 externally. Summarizing the address lessens the amount of entries in the routing table, and increasing the ad to 100 does nothing, as far as I can see, unless there are static routes with an AD between 91 and 99.

Burt

 

[dialerstring]

I was trying to figure this out, but there is a floating static default static with an AD of 250.
0.0.0.0 0.0.0.0 Dialer0 250

 

[jneiberger]

Those are two separate issues, dialerstring. The static route you mention gives the router a default route pointing to the dialer, but it weights it very poorly. I'm guessing that there is another default route in your routing table with a lower AD that is your primary route. If the primary goes away, the backup default route takes its place.

In the case of the summary statement, that instructs the router not to advertise all of the smaller prefixes to the peer when the dialer interface is active. Instead, it will advertise a single summary entry. I don't know why they AD has been changed from default on the summary entry. Perhaps the remote peer has another active route back to the network and the higher AD will help ensure that other routers in the network don't try to send traffic over that dial up link unnecessarily.

 

[dialerstring]

Berger -thanks for the reply... We only have that one static route and we are using bgp to connect to a providers MPLS. I will look at the other end for the configuration.

Thanks guys for you help & input!!!

CCNA
Network Admin