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AD of EIGRP

csco10099624
Level 1
Level 1

I have the following topology ::

R2

|

|

R1--- R3 (ATM (BackBone)

R2, R1 and R3 is running EIGRP AS27. I want R1 to inject default route to R2, I put the command

"ip summary-address eigrp 27 0.0.0.0 0.0.0.0 200" on R1 interface which connects to R2.

The routing table of R2 show the "E* 0.0.0.0" with the AD 90. Why the AD for the default route is 90 ??? instead 200 ?

The IOS version is 12.2(19a).

Thanks!!!!

3 Replies 3

Harold Ritter
Level 12
Level 12

The administrative distance only has local significance. It is normal behavior for that route to have an AD of 90 on R2, which is the default AD. The 200 you set on the summary is the AD you will see locally for the summary route.

Hope this helps,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
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Richard Burts
Hall of Fame
Hall of Fame

In the eigrp summary-address command you have the option to set AD, as you did in the question you asked. This AD is only effective on the router where it is configured. The advertisement that is sent to a neighbor is a normal eigrp internal route advertisement which is given AD of 90 on the receiving router.

HTH

Rick

dmitchell1975
Level 1
Level 1

First of all let us please define AD since we are talking about EIGRP where AD could mean Administrative Distance OR Advertised Distance. From the 90 it seems like you are referring to Administrative Distance, if this is the case, 90 is the default Administrative Distance for the EIGRP protocol and since you used the 'summary-address' command it would be an EIGRP route! You did not inject a default route you injected a summary route, and a very odd one at that! To inject a default route into the EIGRP routing process you would use the 'ip route' command and redistribute the static routes into EIGRP. I would also think that if you were going to do this that R3 would be a better origination point for the default route to the WAN.

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