WARNING[511]: rtp.c:874 ast_rtcp_read: RTCP Read too short

I got a lot of this waring on CLI(Asterisk 1.4):

Also, the IVR seems also get trouble because of this. When caller press a key it sometime generate 20+ lines of the above warning.

I tried to enable SIP debug but it won’t give me more info. I really don’t understand what cause the warning.

My phone is connected through Linksys PAP2. So I tried to change the PAP2 under SIP -> RTP Packet Size. I tried 0.010, 0.020, 0.030(default), 0.040 and it doesn’t make any difference.

please help!


Same warning for me.


Did you guys ever solve this?

I had the same problem when using GSM codec, however problem was only from several PSTNs, while from others was OK. Along with keypresses I was also receiving RTCP Read too short in couple of seconds after WaitExten, even there was no keypress; also was receiveing this error randomly during connection. From those specific PSTNs asterisk was totally unable to get DTMF digits.

Couldn’t found out the reason, but changing gsm to ulaw or alaw codecs totally resolved the problem.

I am not sure if it’s gsm codec causing this, I think it’s up to some specific conditions.

I have noticed that when using GSM files, i got these “read too short” messages if the gsm file length was not a multiple of 33 (Size of gsm blocks) … It seems to have problems with partial blocks at the end …

My solution was to write a conversion program which would not include any uncomplete gsm block at the end of file.

As long as the gsm file length is a multiple of 33 the “read too short” problem doesn’t show …

The DTMF detection may be some other problem …