[asterisk-dev] [Regression issue] Garbage RTP data with Asterisk

[Hans Petter Selasky]

Hi,

 From time to time the Asterisk RTP engine outputs some 4-byte ULAW 
packets (even when the data stream is ALAW), making me believe that the 
packets don't come from the source channel driver. The content of the 
packets is constant: 0x02 0x8A 0x02 0x80

These cause pops/clicks at the receiver. How can the source of these 
packets be found? Is there perhaps a race in Asterisk?

Has anyone seen this issue before. I have a very old installation of 
Asterisk ~v1.6 which does not exhibit this issue.

--HPS

> No.     Time           Source                Destination           Protocol Length Info
>    6032 120.195049000  xx.xx.x.xx            xx.x.x.xx             RTP      204    PT=ITU-T G.711 PCMU, SSRC=0x4CEA3092, Seq=20690, Time=2165120
>
> Frame 6032: 204 bytes on wire (1632 bits), 204 bytes captured (1632 bits) on interface 0
> Null/Loopback
> Internet Protocol Version 4, Src: xx.xx.x.xx (xx.xx.x.xx), Dst: xx.x.x.xx (xx.x.x.xx)
> User Datagram Protocol, Src Port: 27904 (27904), Dst Port: 7078 (7078)
> Real-Time Transport Protocol
>
> No.     Time           Source                Destination           Protocol Length Info
>    6033 120.219922000  xx.xx.x.xx            xx.x.x.xx             RTP      48     PT=ITU-T G.711 PCMU, SSRC=0x4CEA3092, Seq=20691, Time=2165120
>
> Frame 6033: 48 bytes on wire (384 bits), 48 bytes captured (384 bits) on interface 0
> Null/Loopback
> Internet Protocol Version 4, Src: xx.xx.x.xx (xx.xx.x.xx), Dst: xx.x.x.xx (xx.x.x.xx)
> User Datagram Protocol, Src Port: 27904 (27904), Dst Port: 7078 (7078)
> Real-Time Transport Protocol
>
> No.     Time           Source                Destination           Protocol Length Info
>    6034 120.220163000  xx.xx.x.xx            xx.x.x.xx             RTP      48     PT=ITU-T G.711 PCMU, SSRC=0x4CEA3092, Seq=20692, Time=2165120
>
> Frame 6034: 48 bytes on wire (384 bits), 48 bytes captured (384 bits) on interface 0
> Null/Loopback
> Internet Protocol Version 4, Src: xx.xx.x.xx (xx.xx.x.xx), Dst: xx.x.x.xx (xx.x.x.xx)
> User Datagram Protocol, Src Port: 27904 (27904), Dst Port: 7078 (7078)
> Real-Time Transport Protocol
>
> No.     Time           Source                Destination           Protocol Length Info
>    6035 120.221032000  xx.xx.x.xx            xx.x.x.xx             RTP      48     PT=ITU-T G.711 PCMU, SSRC=0x4CEA3092, Seq=20693, Time=2165120
>
> Frame 6035: 48 bytes on wire (384 bits), 48 bytes captured (384 bits) on interface 0
> Null/Loopback
> Internet Protocol Version 4, Src: xx.xx.x.xx (xx.xx.x.xx), Dst: xx.x.x.xx (xx.x.x.xx)
> User Datagram Protocol, Src Port: 27904 (27904), Dst Port: 7078 (7078)
> Real-Time Transport Protocol