Unsolved EIGRP summary route?

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Hi ITPro!

I just discovered that EIGRP "summary" routes have an admin distance of 5 instead of the default 90 for EIGRP. I am familiar with how to summarize routes, would this be an example of a summary route?

R1(config)# router eigrp 1
R1(config-router) network 10.0.0.0

If I am correct this would summarize the entire 10.0.0.0/8 IP space and advertise it via EIGRP? This route would get an admin distance of 5?

Whereas this command would advertise a direct route to the 10.0.0.0/24 network with an admin distance of 90?

R1(config)# router eigrp 1
R1(config-router) network 10.0.0.0 0.0.0.255

Hopefully I am on track so far. What would be the affect of entering something like this that isn't necessarily following the class-full rules? Would this error out or...?

R1(config)# router eigrp 1
R1(config-router) network 10.22.0.0

Regards,
Adam Tyler

@Adam-Tyler said in EIGRP summary route?:

Hi ITPro!

I just discovered that EIGRP "summary" routes have an admin distance of 5 instead of the default 90 for EIGRP. I am familiar with how to summarize routes, would this be an example of a summary route?

R1(config)# router eigrp 1
R1(config-router) network 10.0.0.0

If I am correct this would summarize the entire 10.0.0.0/8 IP space and advertise it via EIGRP? This route would get an admin distance of 5?

If you have multiple subnets like 10.0.0.0/16, 10.0.0.0/20, 10.0.16.0/20, they can be summarized under the 10.0.0.0/8 network. the 10.0.0.0/8 is a summarized network. A summary route is how to get to those networks:
So on R1:

R1#enable
R1#config t
R1(config)#int g0/0
R1(config)#ip summary-route eigrp 1 10.0.0.0 255.0.0.0

Then you go to the neighboring EIGRP router like R2:

R2#show ip route
{note I've just made up the following route as an example}
D     10.0.0.0/8 [90/10642432] via 192.168.16.2, 00:00:29, GigabitEthernet0/0

So It doesn't seem to propagate to another router with an AD of 5 but 90. (I tried this on a real router.)

switch to R1 and type in the show ip route (with the summarized address)

R1#show ip route 10.0.0.0 255.0.0.0
Routing entry for 10.0.0.0/8, supernet
  Known via "eigrp 800", distance 5, metric 10639872, type internal
  Redistributing via eigrp 800
  Routing Descriptor Blocks:
  * directly connected, via Null0
      Route metric is 10639872, traffic share count is 1
      Total delay is 25000 microseconds, minimum bandwidth is 256 Kbit
      Reliability 255/255, minimum MTU 1500 bytes
      Loading 1/255, Hops 0

Hopefully I am on track so far. What would be the affect of entering something like this that isn't necessarily following the class-full rules? Would this error out or...?

R1(config)# router eigrp 1
R1(config-router) network 10.22.0.0

Should work the same way as above.

p.s My apologies for the delayed response, I skipped this one to come back to and didn't see again until tonight because I thought I would have to get access to some routers to test. ~r.

Interesting.. So only the router you configured EIGRP with the summary will use an admin distance of 5? It shows up as 90 on the others.

Regards,
Adam Tyler

With no additional posts, I'm marking this topic as solved. ~RW

I didn't see any comments after my post with this question:

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Interesting.. So only the router you configured EIGRP with the summary will use an admin distance of 5? It shows up as 90 on the others.

Regards,
Adam Tyler
~~

@Adam-Tyler,

I normally leave the question for 5-7 days for additional responses but when this didn't happen, I marked it as solved.

No worries, I just wanted to confirm this was a true statement and I think we are good.

"So only the router you configured EIGRP with the summary will use an admin distance of 5? It shows up as 90 on the others."

Regards,
Adam Tyler

@Adam-Tyler,
As far as I can tell after setting it up in a lab this was the result