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

EIGRP Summarization

I am having trouble configuring EIGRP summarization. Attached is the network diagram. I am using the CCNA virtual lab to configure this.

EIGRP Summarization1.jpg

Router configs:

R1

    --snip--

    interface Serial0/0/0

      ip address 192.168.1.34 255.255.255.252

      no ip directed-broadcast

    !

    interface Serial0/0/1

      ip address 192.168.1.37 255.255.255.252

      no ip directed-broadcast

      clockrate 2000000

    !

    --snip--

    R1#sh ip eigrp top

    IP-EIGRP Topology Table for AS(1)/ID(192.168.1.34)

    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,

           r - reply Status, s - sia Status

    P 10.10.10.8/29, 1 successors, FD is 2172416

             via 192.168.1.38 (2172416/28160), Serial0/0/0

    P 192.168.1.32/30, 1 successors, FD is 2172416

             via Connected, Serial0/0/0

    P 192.168.1.36/30, 1 successors, FD is 2172416

             via Connected, Serial0/0/1

    P 192.168.1.40/30, 1 successors, FD is 2172416

             via 192.168.1.38 (2172416/28160), Serial0/0/0

    P 10.10.10.0/29, 1 successors, FD is 2172416

             via 192.168.1.33 (2172416/28160), Serial0/0/0

    R1#

    interface Serial0/0/0

      ip address 192.168.1.38 255.255.255.252

      no ip directed-broadcast

    !

    interface Serial0/0/1

      ip address 192.168.1.41 255.255.255.252

      no ip directed-broadcast

      clockrate 2000000

    !

    router eigrp 1

     network 192.168.1.0

    R3>en

    R3#sh ip eigrp top

    IP-EIGRP Topology Table for AS(1)/ID(192.168.1.38)

    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,

           r - reply Status, s - sia Status

    P 192.168.1.32/30, 1 successors, FD is 2172416

             via 192.168.1.37 (2172416/28160), Serial0/0/1

    P 10.10.10.8/29, 1 successors, FD is 2172416

             via 192.168.1.42 (2172416/28160), Serial0/0/1

    P 192.168.1.36/30, 1 successors, FD is 2172416

             via Connected, Serial0/0/0

    P 192.168.1.40/30, 1 successors, FD is 2172416

             via Connected, Serial0/0/1

    P 10.10.10.0/29, 1 successors, FD is 2172416

             via 192.168.1.37 (2172416/28160), Serial0/0/1

    R3#

Here is one core router configuration that should be summarizing that block:

    R2 Con0 is now available

    Press RETURN to get started!

    R2>en

    R2#sh run

    Building configuration...

    Current configuration : 874 bytes

    !

    version 12.4

    service timestamps debug datetime msec

    service timestamps log datetime msec

    no service password-encryption

    !

    hostname R2

    !

    boot-start-marker

    boot-end-marker

    !

    !

    !

    !

    no aaa new-model

    !

    !

    ip cef

    !

    !

    !

    !

    !

    ip subnet-zero

    !

    !

    !

    !

    !

    !

    !

    !

    !

    !

    !

    interface FastEthernet0/0

      ip address 10.10.10.1 255.255.255.248

      no ip directed-broadcast

      ip summary-address eigrp 1 192.168.1.32 255.255.255.240

    !

    interface FastEthernet0/1

      no ip address

      no ip directed-broadcast

      shutdown

    !

    interface Serial0/0/0

      ip address 192.168.1.33 255.255.255.252

      no ip directed-broadcast

      clockrate 2000000

    !

    interface Serial0/0/1

      no ip address

      no ip directed-broadcast

      shutdown

      clockrate 2000000

    !

    interface Serial0/1/0

      no ip address

      no ip directed-broadcast

      shutdown

      clockrate 2000000

    !

    interface Serial0/1/1

      no ip address

      no ip directed-broadcast

      shutdown

      clockrate 2000000

    !

    router eigrp 1

     network 10.0.0.0

     network 192.168.1.0

     no auto-summary

    !

    ip classless

    no ip http server

    no ip http secure-server

    !

    !

    !

    !

    !

    !

    control-plane

    !

    !

    !

    !

    line con 0

    line aux 0

    line vty 0 4

      login

    line vty 5 1180

      login

    !

    scheduler allocate 20000 1000

    !

    end

    R2#

    R2>en

    R2#sh ip eigrp top

    IP-EIGRP Topology Table for AS(1)/ID(192.168.1.33)

    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,

           r - reply Status, s - sia Status

    P 10.10.10.8/29, 1 successors, FD is 2172416

             via null (2172416/28160), FastEthernet0/8

    P 192.168.1.32/30, 1 successors, FD is 2172416

             via Connected, Serial0/0/0

    P 192.168.1.36/30, 1 successors, FD is 2172416

             via 192.168.1.34 (2172416/28160), Serial0/0/0

    P 192.168.1.40/30, 1 successors, FD is 2172416

             via 192.168.1.34 (2172416/28160), Serial0/0/0

    P 10.10.10.0/29, 1 successors, FD is 2172416

             via Connected, FastEthernet0/0

    R2#

R2>en

R2#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

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       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, o - ODR, P - periodic downloaded static route

       T - traffic engineered route

Gateway of last resort is not set

    10.0.0.0/29 is subnetted, 2 subnets

D     10.10.10.8 [90/2172416] via 10.10.10.9, 01:31:30, FastEthernet0/0

C     10.10.10.0 is directly connected, FastEthernet0/0

    192.168.1.0/30 is subnetted, 3 subnets

C     192.168.1.32 is directly connected, Serial0/0/0

D     192.168.1.36 [90/2172416] via 192.168.1.34, 01:31:30, Serial0/0/0

D     192.168.1.40 [90/2172416] via 192.168.1.34, 01:31:30, Serial0/0/0

R2#

I used a 16 block for the /30 addresses between each serial link. The starting IP is 192.168.1.33, with the network ID being 192.168.1.32.

There is complete connectivity between all devices, but it will not summarize all of the /30's into a single 16 block of .240.

I added in the "auto-summary" command on R1 and R3, and "no auto-summary" on R2 and R4 anyway but it didn't change anything. I'm not sure what I'm missing.

2 REPLIES
Silver

Re: EIGRP Summarization

You can look at this link

In addition, your IPs in 10.10.10.0/29 range seems to be out of range. Valid IPs are only from 10.10.10.1 to 10.10.10.6 for /29

Thanks.

Hall of Fame Super Blue

Re: EIGRP Summarization

Just labbed this up with dynamips and it works as expected ie.

if you turn on auto-summary on R2 & R4 then the 3560 switch just sees 2 entries for 192.168.1.0/24

if you use the ip summary-address eigrp .. command on the interfaces facing the 3560 then the 3560 switch sees 2 entries for 192.168.1.32/28.

So it all works as expected. Remember that you will only see the effects of summarisation on the 3560 and not on any of the other routers.

I'm assuming your 3560 is running as a L3 switch and is an EIGRP peer with R2 & R4.

Jon

547
Views
0
Helpful
2
Replies
CreatePlease to create content