Why can't change EIGRP summary route administrative distance?

Answered Question
Oct 9th, 2009
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Router A and B are running 12.3(22). I configured a EIGRP summary route on router A interface toward B with various administrative distance values. But in router B routing table, the summary route is alway EIGRP route with distance 90.


Router A:

interface Ethernet 0/0

ip summary-address eigrp 1 192.168.0.0 255.255.0.0


Router B routing table:

D 192.168.0.0/16 [90/2684416] via 172.20.1.1, 00:00:30, Ethernet0/0


Isn't the summary router default to administrative distance of 5?


Thanks a lot


Correct Answer by Lucien Avramov about 7 years 9 months ago

R2(config-if)#do sh ip route 192.168.0.0

Routing entry for 192.168.0.0/16, supernet

Known via "eigrp 1", distance 5, metric 28160, type internal

Redistributing via eigrp 1

Routing Descriptor Blocks:

* directly connected, via Null0

Route metric is 28160, traffic share count is 1

Total delay is 100 microseconds, minimum bandwidth is 100000 Kbit

Reliability 255/255, minimum MTU 1500 bytes

Loading 1/255, Hops 0


Thats the type of output you will see.


Great I guess we can mark this post resolved.


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Jerry Ye Fri, 10/09/2009 - 18:39
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Distance value is locally significant.


When you configured summary address in router A, the admin distance of the summary route is 5. When router A send the route to router B, router B will see it as a native EIGRP route and assign it with a admin distance value of 90.


HTH,

jerry

Lucien Avramov Fri, 10/09/2009 - 18:42
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That changes the admin distance to 5 on router A.


Do a show ip route 192.168.0.0 on router A and you will see a route to null0 with an admin distance of 5.



gwhuang5398 Fri, 10/09/2009 - 19:03
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Thanks a lot. Somehow on router A routing table, it only shows the summary route to Null0, with no distance value attached.


I misunderstood that router B would give the received summary route a distance value 5. Now it's clear.


Thanks again

Correct Answer
Lucien Avramov Fri, 10/09/2009 - 19:16
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R2(config-if)#do sh ip route 192.168.0.0

Routing entry for 192.168.0.0/16, supernet

Known via "eigrp 1", distance 5, metric 28160, type internal

Redistributing via eigrp 1

Routing Descriptor Blocks:

* directly connected, via Null0

Route metric is 28160, traffic share count is 1

Total delay is 100 microseconds, minimum bandwidth is 100000 Kbit

Reliability 255/255, minimum MTU 1500 bytes

Loading 1/255, Hops 0


Thats the type of output you will see.


Great I guess we can mark this post resolved.


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