[nsp] CEF problem on 6509 (native)

[Jack.W.Parks at alltel.com]

Did you happen to readdress the link with a new IP address?  For
example:  The link toward the CMTS was 1.1.1.1/30, but recently you
changed it to 2.2.2.1/30.

We have had many problems related to this type of change and CEF.  The
ONLY fix was to reload the router after any destination next-hop change.

Jack

Jack W. Parks IV
Sr. Network Engineer
ALLTEL Communications
jack.w.parks at remove-me.alltel.com
Work: 501-905-5961
Cell: 501-680-3341
   

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Sorin
CONSTANTINESCU
Sent: Wednesday, November 12, 2003 1:42 PM
To: cisco-nsp at puck.nether.net
Subject: Re: [nsp] CEF problem on 6509 (native)



Hi,

I found out what the problem is (with some help from the list), but i
don't know how i can get rid of it.

The router has a mls cef entry for x.y.z.25 different from x.y.z.0/24,
when in the routing table i have only entry, for x.y.z.0/24:

r2#show mls cef x.y.z.0 255.255.255.0

Index      Prefix           Mask                Adjacency
13429      x.y.z.0       255.255.255.0       00d0.0568.980a
r2#show mls cef x.y.z.25 255.255.255.255

Index      Prefix           Mask                Adjacency
2240       x.y.z.25      255.255.255.255     00a0.d2a4.5003
r2#

This client is connected via a cable-modem. The CMTS is Cuda (router,
not bridge).

I don't get it from where does this router learn that mls cef entry. The
layer3 path is

r2 --> r1 --> CUDA CMTS --> client

I've even monitored CUDA's traffic for 00a0.d2a4.5003 or x.y.z.25 to see
what packets come/go when the mls cef entry is renewed, but i haven't
seen any.

r2 does not have any interface in the vlan in which the CUDA CMTS is
connected.

I really don't know what to do next. If there's anything i forgot to
add, please drop pe an email.

Thanks!
-- 
Sorin CONSTANTINESCU
adonay at dumnez.eu.org
Linux Registered User #222086

> On 11/11/03 2:35 AM, "Sorin CONSTANTINESCU" <adonay at dumnez.eu.org> 
> wrote:
>
>> Hi,
>>
>> One of our Cat6500 routers' CEF is acting strangely. The router 
>> wouldn't forward traffic towards x.y.z.25, but it would for x.y.z.26.

>> CEF has an entry for x.y.z/24 (known by the router from BGP).
>>
>> If i put an ACL on a VLAN (in) with permit for x.y.z.25, traffic 
>> coming via that vlan will be routed, but only the traffic coming via 
>> that vlan.
>>
>> The temporary solution was to have a route for x.y.z.25.
>>
>> The 6509 has msfc2/sup2, and runs Version 12.1(19)E (native). I 
>> looked for CEF bugs using cisco's bugtool, but none match
>  my case.
>>
>> Does anybody have a clue on how to solve this problem?
>>
>> Regards,
>

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