[nsp] CEF problem on 6509 (native)

Sorin CONSTANTINESCU adonay at dumnez.eu.org
Thu Nov 13 01:13:37 EST 2003


No, the address is the same for 2 months, at least.

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

Jack.W.Parks at alltel.com said:
> 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 th
> is 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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