Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Discontiguous networks still advertised ?

I have a network with 4 routers all running EIGRP. I added 2 discontiguous networks, and EIGRP is distributing those networks as valid routes. It was my understanding that the only way this is supposed to work is if auto-summary is disabled. What am I overlooking? I have run no auto-summary on all the routers but the discontiguous network is still being distributed in all routing tables. (?)

RE#sh ip protocols
Routing Protocol is "eigrp 10"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
EIGRP maximum hopcount 100
EIGRP maximum metric variance 1
Redistributing: eigrp 10
Automatic network summarization is in effect
Routing for Networks:
10.0.0.0
Routing Information Sources:
Gateway Distance Last Update
10.0.32.1 90 00:05:56
10.0.128.1 90 00:05:56
Distance: internal 90 external 170
RE#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route
Gateway of last resort is not set
10.0.0.0/20 is subnetted, 3 subnets
D 10.0.16.0 [90/2681856] via 10.0.32.1, 00:12:52, Serial1
C 10.0.32.0 is directly connected, Serial1
C 10.0.128.0 is directly connected, Serial0
D 192.168.32.0/24 [90/2707456] via 10.0.32.1, 00:11:39, Serial1
D 192.168.33.0/24 [90/2172416] via 10.0.128.1, 00:11:00, Serial0

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Blue

Re: Discontiguous networks still advertised ?

stevec90@yahoo.com

I have a network with 4 routers all running EIGRP. I added 2 discontiguous networks, and EIGRP is distributing those networks as valid routes. It was my understanding that the only way this is supposed to work is if auto-summary is disabled. What am I overlooking? I have run no auto-summary on all the routers but the discontiguous network is still being distributed in all routing tables. (?)

RE#sh ip protocols
Routing Protocol is "eigrp 10"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
EIGRP maximum hopcount 100
EIGRP maximum metric variance 1
Redistributing: eigrp 10
Automatic network summarization is in effect
Routing for Networks:
10.0.0.0
Routing Information Sources:
Gateway Distance Last Update
10.0.32.1 90 00:05:56
10.0.128.1 90 00:05:56
Distance: internal 90 external 170
RE#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route
Gateway of last resort is not set
10.0.0.0/20 is subnetted, 3 subnets
D 10.0.16.0 [90/2681856] via 10.0.32.1, 00:12:52, Serial1
C 10.0.32.0 is directly connected, Serial1
C 10.0.128.0 is directly connected, Serial0
D 192.168.32.0/24 [90/2707456] via 10.0.32.1, 00:11:39, Serial1
D 192.168.33.0/24 [90/2172416] via 10.0.128.1, 00:11:00, Serial0

Steve

Summary or no auto-summary will make no difference with 192.168.x.0/24 networks because there is no summarising to be done on these networks ie. they are class C networks anyway. Summarisation happens on classful boundaries but 192.168.32.0/24 and 192.168.33.0/24 are classful ie. class C networks.

If you want to test try using 172.16.x.0/24 networks because this is a class B network ie. 172.16.0.0/16.

Jon

1 REPLY
Hall of Fame Super Blue

Re: Discontiguous networks still advertised ?

stevec90@yahoo.com

I have a network with 4 routers all running EIGRP. I added 2 discontiguous networks, and EIGRP is distributing those networks as valid routes. It was my understanding that the only way this is supposed to work is if auto-summary is disabled. What am I overlooking? I have run no auto-summary on all the routers but the discontiguous network is still being distributed in all routing tables. (?)

RE#sh ip protocols
Routing Protocol is "eigrp 10"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
EIGRP maximum hopcount 100
EIGRP maximum metric variance 1
Redistributing: eigrp 10
Automatic network summarization is in effect
Routing for Networks:
10.0.0.0
Routing Information Sources:
Gateway Distance Last Update
10.0.32.1 90 00:05:56
10.0.128.1 90 00:05:56
Distance: internal 90 external 170
RE#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route
Gateway of last resort is not set
10.0.0.0/20 is subnetted, 3 subnets
D 10.0.16.0 [90/2681856] via 10.0.32.1, 00:12:52, Serial1
C 10.0.32.0 is directly connected, Serial1
C 10.0.128.0 is directly connected, Serial0
D 192.168.32.0/24 [90/2707456] via 10.0.32.1, 00:11:39, Serial1
D 192.168.33.0/24 [90/2172416] via 10.0.128.1, 00:11:00, Serial0

Steve

Summary or no auto-summary will make no difference with 192.168.x.0/24 networks because there is no summarising to be done on these networks ie. they are class C networks anyway. Summarisation happens on classful boundaries but 192.168.32.0/24 and 192.168.33.0/24 are classful ie. class C networks.

If you want to test try using 172.16.x.0/24 networks because this is a class B network ie. 172.16.0.0/16.

Jon

709
Views
0
Helpful
1
Replies
CreatePlease to create content