Weird 3750 error

[jigsaw2026]

Hi,

Has anyone come across this before? I have a Cat 3750 running IOS 12.2(25)SEC. Over the last couple of days we've had a few problems and have shutdown a tunnel a couple of times. In the logs (although not necessarily at the same time) the following has appeared:

%PLATFORM_HCEF-3-ADJ: Insane handle in add LT7

I can't find any info on it anywhere...does anyone have any ideas? Is it something to do with Cef running on the tunnel?

Many thanks in advance,

J2026

[amohabir1]

I found a posting in Russian on the web. That person said they started getting those errors when theu enabled ip accounting on the interface.

[jigsaw2026]

Thanks a lot for your reply, unfortunately we haven't enabled ip accounting on any interfaces, so I'm pretty certain it's not that.

[adam.marsolek]

This may help you find an answer... Try issuing the "debug all", but any users connected may lose network connectivity. Run the "show debug all".

[jigsaw2026]

Hmmm unfortunately it's more than my life's worth to risk a running a debug all! But you're right, perhaps I will just have to wait until we have some downtime.

Thanks for your response, much appreciated.

[ajagadee]

Hi,

Are you using the Tunnel Interface for Unicast Traffic or DVMRP.

A Catalyst 3750 switch does not support tunnel interfaces for unicast routed traffic. Only Distance Vector Multicast Routing Protocol (DVMRP) tunnel interfaces are supported for multicast routing.

Please refer the below URLs for details:

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3750/12218se/ol502302.htm#wp528230

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3750/12225see/ol8556.htm

If you are using the Tunnel Interface for DVMRP, could you post the running configuration of the tunnel interface.

I hope it helps.

Regards,

Arul

[jigsaw2026]

Hi Arul,

Many thanks for your help.

We are not running DVMRP, the tunnel is for used for unicast routed traffic. It's interesting because if that's the case, why does it only error when a tunnel is brought up or down, and otherwise carry unicast traffic normally?

Also, the links that you sent me weren't for 12.2(25)SEC - do you think that they apply generally for 3750s?

Regards,

J2026

[ajagadee]

Leanne,

Here is my understanding of Tunnel Interface and Unicast Traffic on 3750 switches based on configuring and testing the feature in lab.

You could configure a Tunnel interface and have unicast traffic through it and it should work fine. Atleast it did in my lab set up and no packet loss.

And for encapsulating/decapsulating GRE headers, I "think" the packets are sent to CPU, that is software switched and not hardware switched. So, a possible performance hit in production environment based upon the network/traffic.

Below are the lessons that I learnt:

1. Officially Unicast Routed Traffic is not supported on Tunnel Interface in 3750 switches.

2. There is a performance cost associated with Tunnel Interface and Unicast traffic on 3750 since the packets are not hardware switched.

3. If there are any issues related to Tunnel/Unicast Traffic, it is going to be challenging trying to get support from TAC and Development Team since the feature is not supported.

I hope it helps.

Please let me know if you have any additional questions.

Regards,

Arul