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

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

rtp header compression question

Hi all,

I have two Cisco 1750 routers at 2 remote sites running VOIP that qos & rtp compression commands are used but one of the routers seems to "hang" occasionally each time(not every time) it accepts an incoming telnet session, since then I cannot ping the router and it will sometimes reboot itself and sometimes remains "hang" until cold rebooted locally.

A partial output of "show version" shows:

Router uptime is 16 minutes

System returned to ROM by error - a SegV exception, PC 0x8083A98C at 14:29:55 CST Tue

Feb 5 2002

System restarted at 09:46:06 CST Wed Feb 20 2002

System image file is "flash:c1700-sv3y-mz.121-3.T"


My question is Have you VOIP experts encountered this before? Is this a hardware issue? I am particularly puzzled with the meaning of "SegV exception, PC 0x8083A98C" error, which seems to have appeared after I issued rtp compression commands on the router (but no such symptom for the other router)

Any ideas why?

Many thanks in advance,


Cisco Employee

Re: rtp header compression question

I have not seen an issue like this before. If you are getting a segv and it is crashing the router I suggest opening a TAC case to troubleshoot the crash. Did you notice if when you put on the rtp header compression is the command tcp header compression also being added? I have seen this before and you can try removing the tcp header compression.

Hope this helps,


Cisco Employee

Re: rtp header compression question

As far as I know, you can't remove tcp header-compression without rtp header-compression also being removed.

You should definitely call TAC about this problem so they can look at the stack trace and determine if this is a known issue. You are definitely not running ideal code.

New Member

Re: rtp header compression question

Thanks gentlemen,

Asthe encapsulation used is frame-relay, I am free to add/remove "frame ip rtp header" or "frame ip tcp header" on the sub i/f of serial port.

However I do wonder according to common practice if the "rtp/tcp header" commands should be issued also on the serial port, apart from the sub-i/f concerned.



New Member

Re: rtp header compression question


I've deployed a solution very simliar to yours.

Two 1750 running VOIP and Crypto tunnels.

I configured MLPPP with CRTP, LFI and it works excelent. I've just checked, and both are running without problems for 6 weeks.

The IOS installed is c1700-k8sv3y-mz.122-5.bin

New Member

Re: rtp header compression question

From my expiriance implementing many gateways on various platforms is whenever gateway reboots itself it could be an issue of insufficiant memory.

Please check that...

New Member

Re: rtp header compression question

I'm not sure about what happens in your case. But I'd ask you why you run such an old release. Why don't you download something like 12.2(1) or better?

Also, I have found several bugs regarding RTP header compreesion on the Cisco platform. So, going to a newer release could help you in this issue too.

New Member

Re: rtp header compression question

Gentleman, I told you that I've do this, and it WORKS PERFECCT.

If you see my previous email, you will find the IOS that I'am using, so I recommend to change the version and try again.

New Member

Re: rtp header compression question

Hi salata,

I've changed the ios image to a newer version(though not as new as yours) and is observing if it will malfunction again..