RIP manual summarization being weird

I'm just plaing with RIP manual summarizaion, and its not playing nice....  Hoping someone can help me out here.

Here is some config on a router(R4) that is receiving a few 172.16.x.x/24 routes from R12:

R4(config-if)#do sh ip route rip | in 172.16.
     172.16.0.0/24 is subnetted, 4 subnets
R       172.16.4.0 [120/1] via 204.12.1.254, 00:00:19, GigabitEthernet3/0
R       172.16.1.0 [120/1] via 204.12.1.254, 00:00:19, GigabitEthernet3/0
R       172.16.2.0 [120/1] via 204.12.1.254, 00:00:19, GigabitEthernet3/0
R       172.16.3.0 [120/1] via 204.12.1.254, 00:00:19, GigabitEthernet3/0

On R4 I want to summarize these 172.16.x routes, so I do this under the interface:

R4(config-if)#ip summary-address rip 172.16.0.0 255.255.0.0

 

Howvever when I do this, the router (R5) that this summary gets advertised to just doesn't seem to get the route

R5#sh ip route | in 172.16
     172.16.0.0/24 is subnetted, 4 subnets
R       172.16.4.0 [120/2] via 155.1.45.4, 00:01:13, Serial1/1
R       172.16.1.0 [120/2] via 155.1.45.4, 00:01:13, Serial1/1
R       172.16.2.0 [120/2] via 155.1.45.4, 00:01:13, Serial1/1
R       172.16.3.0 [120/2] via 155.1.45.4, 00:01:13, Serial1/1
R5#

Then after a while all the 172.16.x routes are removed from the routing table:

R5#sh ip route | in 172.16
     172.16.0.0/24 is subnetted, 4 subnets
R       172.16.4.0/24 is possibly down,
R       172.16.1.0/24 is possibly down,
R       172.16.2.0/24 is possibly down,
R       172.16.3.0/24 is possibly down,

R5#sh ip route | in 172.16

R5#sh ip route | in 172.16

Nothing.... removing the manual summary restores the individual /24 routes... 

I can't see what i'm doing wrong here - R4 and R5 are connected over the 155.1.45.0/24.  If i use auto summariztion it works fine.

This is done in a dynamips lab running IOS 12.4(11)T

Any thoughts??

 

 

Comments

  • What interface are you putting the summary command on? It needs to be on the one facing R5. 

    Once on you should be able to see the summary in the RIP database on R4. 

    David

    Sent from my iPhone
    Please excuse any mistakes and brevity. 

    On 1 Sep 2012, at 07:56, Luca <[email protected]> wrote:

    I'm just plaing with RIP manual summarizaion, and its not playing nice....  Hoping someone can help me out here.

    Here is some config on a router(R4) that is receiving a few 172.16.x.x/24 routes from R12:

    R4(config-if)#do sh ip route rip | in 172.16.
         172.16.0.0/24 is subnetted, 4 subnets
    R       172.16.4.0 [120/1] via 204.12.1.254, 00:00:19, GigabitEthernet3/0
    R       172.16.1.0 [120/1] via 204.12.1.254, 00:00:19, GigabitEthernet3/0
    R       172.16.2.0 [120/1] via 204.12.1.254, 00:00:19, GigabitEthernet3/0
    R       172.16.3.0 [120/1] via 204.12.1.254, 00:00:19, GigabitEthernet3/0

    On R4 I want to summarize these 172.16.x routes, so I do this under the interface:

    R4(config-if)#ip summary-address rip 172.16.0.0 255.255.0.0

     

    Howvever when I do this, the router (R5) that this summary gets advertised to just doesn't seem to get the route

    R5#sh ip route | in 172.16
         172.16.0.0/24 is subnetted, 4 subnets
    R       172.16.4.0 [120/2] via 155.1.45.4, 00:01:13, Serial1/1
    R       172.16.1.0 [120/2] via 155.1.45.4, 00:01:13, Serial1/1
    R       172.16.2.0 [120/2] via 155.1.45.4, 00:01:13, Serial1/1
    R       172.16.3.0 [120/2] via 155.1.45.4, 00:01:13, Serial1/1
    R5#

    Then after a while all the 172.16.x routes are removed from the routing table:

    R5#sh ip route | in 172.16
         172.16.0.0/24 is subnetted, 4 subnets
    R       172.16.4.0/24 is possibly down,
    R       172.16.1.0/24 is possibly down,
    R       172.16.2.0/24 is possibly down,
    R       172.16.3.0/24 is possibly down,

    R5#sh ip route | in 172.16

    R5#sh ip route | in 172.16

    Nothing.... removing the manual summary restores the individual /24 routes... 

    I can't see what i'm doing wrong here - R4 and R4 are connected over the 155.1.45.0/24.  If i use auto summariztion it works fine.

    This is done in a dynamips lab running IOS 12.4(11)T

    Any thoughts??

     

     




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  • Yeah it is on the interface connecting to R5:

    R4(config-if)#do sh run int s1/0
    Building configuration...

    Current configuration : 252 bytes
    !
    interface Serial1/0
     ip address 155.1.45.4 255.255.255.0
     ip summary-address rip 172.16.0.0 255.255.0.0

     

    R4(config-if)#do sh cdp ne s1/0
    Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                      S - Switch, H - Host, I - IGMP, r - Repeater

    Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
    R5.lab.local     Ser 1/0            159           R       7206VXR   Ser 1/1

  • Anything useful in the output of "debug ip rip?"
  • Not really, couldn't see anything specific.

     

    I think its a bug.  I tried the same config during a INE rack session and it worked like normal.

    Might change the IOS i use in Dynamips and see if that helps.

  • What version are you using?

    Sent from my iPhone
    Please excuse any mistakes and brevity. 

    On 1 Sep 2012, at 23:22, Luca <[email protected]> wrote:

    Not really, couldn't see anything specific.

     

    I think its a bug.  I tried the same config during a INE rack session and it worked like normal.

    Might change the IOS i use in Dynamips and see if that helps.




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  • It might be a bug, but...

     

    Is split-horizon enabled?

    http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_rip/command/irr-cr-rip.html#GUID-A7238591-6B47-41B3-B084-024F592CF8AB


    Note



    If split horizon is enabled, neither autosummary nor interface summary addresses (those configured with the ip summary-address rip command) are advertised.
  • I've just labbed it out to make sure I was right in my head and split-horizon doesnt come into this issue as you are summarising out of a different interface.

     

    In my testing I did a simple R2 -> R1 -> R3 setup with R2 announcing a number of networks that R1 was then summarising out toward R3.

    It worked exactly as I thought it would, once the summary had been added the summary was seen on R3 and eventually the individual routes timed out.

     

    For reference I'm using 12.4(15)T14 on 3745's

  • Hi Luca,

    I think reload will solve.

    check this cisco's link:

    http://www.cisco.com/en/US/docs/ios/12_4t/release/notes/124TCAVS2.html

     





    CSCsl56934

    Symptoms: "ip summary-address rip" is
    configured on an interface, but the summary address is not advertised by RIP.

    Conditions: Occurs, after the same interface was
    deleted and re-created with "ip summary-address rip" configured on it
    (e.g Virtual Access interface or Loopback). Originally observed when connecting
    and disconnecting virtual access sessions. The issue is platform-independent.

    Workaround: There is no workaround.


     

     

  • Which lab/question number ur practicing.

  • I tried it on a different IOS - exact same configuration and it worked fine.

    I'd say a bug in the IOS i was running

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