Asterisk gives Unknown RTP codec 126


We are using our own softphone, based on an SDK from Port SIP (
The softphone uses to send RPT Payload 126 as RTP Keepalive, and at the asterisk console we get the following message:

NOTICE[-1] res_rtp_asterisk.c: Unknown RTP codec 126 received from ‘’

Any ideas on how to fix this?

I’m using Asterisk Ver.

As Asterisk will never send SDP permitting the use of codec 126, the client is broken to try and use it.

Although Asterisk is actually more restrictive in which codecs it will use for sending, the SDP sent from a user agent identifies the codecs it is prepared to receive. The other user agent should not try and use a codec that was not included in the incoming SDP.

I also doubt if 126 is a reserved codec number, so Asterisk would also have to send a codec number to codec name mapping in its SDP.

It appears to me that Asterisk is behaving perfectly correctly.