[cisco-voip] Comfort noise RTP

Mon Aug 12 13:45:16 EDT 2013

You need the rest of the SIP dialogue. you sent the SDP offer in the
invite, but that doesnt mean they didnt counter with different caps or
a= lines. please post everything from the INVITE though the ACK to the
200 OK. This should shed some light on the behavior.

-Peter

On Thu, Aug 8, 2013 at 6:33 AM, Seth McGuinness
<Seth.McGuinness at imaginegroup.ie> wrote:
> Hello All,
>
>
>
> We have a customer complaining about Comfort Noise generating from our Cisco
> AS5400, strange thing is that the packet traces suggest that the request for
> comfort noise generation comes from the client SIP invite, I can’t see where
> this is the case in the invite.
>
>
>
> Client invite
>
>
>
> No.     Time                  Source     Destination Protocol Length Info
>
> 1 2013-08-07 09:21:34.500695  10.10.1.1  192.168.1.1 SIP/SDP  1131
> Request: INVITE sip:+197831111111149 at 192.168.1.1;user=phone, with session
> description
>
>
>
> Frame 1: 1131 bytes on wire (9048 bits), 1131 bytes captured (9048 bits)
>
> Ethernet II, Src: WwPcbaTe_11:11:11 (00:0f:1f:11:11:11), Dst:
> BrocadeC_22:22:22 (00:1b:ed:22:22:22)
>
> Internet Protocol Version 4, Src: 10.10.1.1(10.10.1.1), Dst: 192.168.1.1
> (192.168.1.1)
>
> User Datagram Protocol, Src Port: sip-tls (5061), Dst Port: sip (5060)
>
> Session Initiation Protocol
>
>     Request-Line: INVITE sip:+197831111111149 at 192.168.1.1;user=phone SIP/2.0
>
>     Message Header
>
>     Message Body
>
>         Session Description Protocol
>
>             Session Description Protocol Version (v): 0
>
>             Owner/Creator, Session Id (o): - 1375863694 1375863694 IN IP4
> 10.10.1.1
>
>                 Owner Username: -
>
>                 Session ID: 1375863694
>
>                 Session Version: 1375863694
>
>                 Owner Network Type: IN
>
>                 Owner Address Type: IP4
>
>                 Owner Address: 10.10.1.1
>
>             Session Name (s): -
>
>             Connection Information (c): IN IP4 10.10.1.1
>
>                 Connection Network Type: IN
>
>                 Connection Address Type: IP4
>
>                 Connection Address: 10.10.1.1
>
>             Time Description, active time (t): 0 0
>
>                 Session Start Time: 0
>
>                 Session Stop Time: 0
>
>             Media Description, name and address (m): audio 33870 RTP/AVP 8 0
> 18 101
>
>                 Media Type: audio
>
>                 Media Port: 33870
>
>                 Media Protocol: RTP/AVP
>
>                 Media Format: ITU-T G.711 PCMA
>
>                 Media Format: ITU-T G.711 PCMU
>
>                 Media Format: ITU-T G.729
>
>                 Media Format: DynamicRTP-Type-101
>
>             Media Attribute (a): rtpmap:8 PCMA/8000
>
>                 Media Attribute Fieldname: rtpmap
>
>                 Media Format: 8
>
>                 MIME Type: PCMA
>
>                 Sample Rate: 8000
>
>             Media Attribute (a): rtpmap:0 PCMU/8000
>
>                 Media Attribute Fieldname: rtpmap
>
>                 Media Format: 0
>
>                 MIME Type: PCMU
>
>                 Sample Rate: 8000
>
>             Media Attribute (a): rtpmap:18 G729/8000
>
>                 Media Attribute Fieldname: rtpmap
>
>                 Media Format: 18
>
>                 MIME Type: G729
>
>                 Sample Rate: 8000
>
>             Media Attribute (a): fmtp:18 annexb=no
>
>                 Media Attribute Fieldname: fmtp
>
>                 Media Format: 18 [G729]
>
>                 Media format specific parameters: annexb=no
>
>             Media Attribute (a): rtpmap:101 telephone-event/8000
>
>                 Media Attribute Fieldname: rtpmap
>
>                 Media Format: 101
>
>                 MIME Type: telephone-event
>
>                 Sample Rate: 8000
>
>             Media Attribute (a): fmtp:101 0-15
>
>                 Media Attribute Fieldname: fmtp
>
>                 Media Format: 101 [telephone-event]
>
>                 Media format specific parameters: 0-15
>
>             Media Attribute (a): sendrecv
>
>             Media Attribute (a): silenceSupp:off - - - -
>
>                 Media Attribute Fieldname: silenceSupp
>
>                 Media Attribute Value: off - - - -
>
>
>
>
>
> Our response
>
>
>
> No.     Time                       Source         Destination
> Protocol Length Info
>
> 2       2013-08-07 09:21:41.862610 192.168.1.1    10.10.1.1             RTP
> 60     PT=Comfort noise, SSRC=0x8FED3F6, Seq=28259, Time=1374861414
>
>
>
> Frame 7: 60 bytes on wire (480 bits), 60 bytes captured (480 bits)
>
> Ethernet II, Src: BrocadeC_22:22:22 (00:1b:ed:22:22:22), Dst:
> WwPcbaTe_11:11:11 (00:0f:1f:11:11:11)
>
> Internet Protocol Version 4, Src: 192.168.1.1 (192.168.1.1), Dst:
> 10.10.1.1(10.10.1.1)
>
> User Datagram Protocol, Src Port: 19578 (19578), Dst Port: 33870 (33870)
>
> Real-Time Transport Protocol
>
>     [Stream setup by SDP (frame 1)]
>
>     10.. .... = Version: RFC 1889 Version (2)
>
>     ..0. .... = Padding: False
>
>     ...0 .... = Extension: False
>
>     .... 0000 = Contributing source identifiers count: 0
>
>     0... .... = Marker: False
>
>     Payload type: Comfort noise (13)
>
>     Sequence number: 28259
>
>     [Extended sequence number: 93795]
>
>     Timestamp: 1374861414
>
>     Synchronization Source identifier: 0x08fed3f6 (150918134)
>
>     Payload: 48
>
>
>
> In our RTP Comfort noise payload type 13 in frame(2) it states that the
> Stream has been setup by SDP in frame 1, I can’t see this in frame 1, it has
> silence suppression turned off and annexb=no, the RTP stream is G.711
> anyway, I left out the whole capture for brevity. Has anyone come across
> this? Any suggestions appreciated and apologies if I post this in the wrong
> place!
>
>
>
> Cheers
>
>
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