[Asterisk-Users] SIP Call Seq Error (SIP/2.0 481 Invalid CSeq Number)

Thu Oct 23 04:55:11 MST 2003

Hi all:

I've no response for the last question with the same subject. Please excuse
me for the extreme length of this mail, but I send 2 SIP traces.

I have problem with * and 5300, when the incoming and outgoing call are
routed thru the same SIP gateway (AS5300). Do I need to set an special
things in sip.conf?
First all, the * printout. Second, the 5300 trace.

Thanks in advace,

Gus

noc2pbx*CLI> show version
Asterisk CVS-10/22/03-12:37:21 built by root at noc2pbx on a i686 running Linux
noc2pbx*CLI>

==========================================================

    -- Executing Dial("SIP/-081221b0", "SIP/99952880474 at 200.61.32.142") in
new stack
    -- Called 99952880474 at 200.61.32.142
    -- SIP/200.61.32.142-029e is ringing
    -- SIP/200.61.32.142-029e answered SIP/-081221b0
    -- Attempting native bridge of SIP/-081221b0 and SIP/200.61.32.142-029e
    -- Got SIP response 481 "Invalid CSeq Number" back from 200.61.32.142
  == Spawn extension (default, 2003, 1) exited non-zero on 'SIP/-081221b0'
    -- Got SIP response 481 "Invalid CSeq Number" back from 200.61.32.142
    -- Got SIP response 481 "Invalid CSeq Number" back from 200.61.32.142

========================== 5300 ==========================

arbue002gw01#
Oct 22 09:19:49.922: Sent:
INVITE sip:2003 at 200.61.32.238;user=phone;phone-context=unknown SIP/2.0
Via: SIP/2.0/UDP  200.61.32.142:5060
From: "52880472" <sip:52880472 at 200.61.32.142>
To: <sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>
Date: Wed, 22 Oct 2003 09:19:49 ARBUE
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
Cisco-Guid: 3723068367-62919128-3200036283-3383986922
User-Agent: Cisco VoIP Gateway/ IOS 12.x/ SIP enabled
CSeq: 101 INVITE
Max-Forwards: 6
Timestamp: 1066825189
Contact: <sip:52880472 at 200.61.32.142:5060;user=phone>
Expires: 180
Content-Type: application/sdp
Content-Length: 166

v=0
o=CiscoSystemsSIP-GW-UserAgent 624 4121 IN IP4 200.61.32.142
s=SIP Call
c=IN IP4 200.61.32.142
t=0 0
m=audio 20476 RTP/AVP 8 0 18 65535 65535 65535 4 65535

Oct 22 09:19:49.930: Received:
SIP/2.0 100 Trying
Via: SIP/2.0/UDP  200.61.32.142:5060
From: "52880472" <sip:52880472 at 200.61.32.142>
To: <sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 101 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Contact: <sip:2003 at 200.61.32.238>
Content-Length: 0

Oct 22 09:19:49.930: Received:
INVITE sip:99952880474 at 200.61.32.142 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>
Contact: <sip:52880472 at 200.61.32.238>
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 102 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Content-Type: application/sdp
Content-Length: 261

v=0
o=root 20500 20500 IN IP4 200.61.32.238
s=session
c=IN IP4 200.61.32.238
t=0 0
m=audio 15740 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 12476 RTP/AVP

Oct 22 09:19:49.938: Sent:
SIP/2.0 100 Trying
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>
Date: Wed, 22 Oct 2003 09:19:49 ARBUE
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
Server: Cisco VoIP Gateway/ IOS 12.x/ SIP enabled
CSeq: 102 INVITE
Content-Length: 0

Oct 22 09:19:51.162: Sent:
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>
Date: Wed, 22 Oct 2003 09:19:49 ARBUE
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
Server: Cisco VoIP Gateway/ IOS 12.x/ SIP enabled
CSeq: 102 INVITE
Content-Length: 0

Oct 22 09:19:51.166: Received:
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP  200.61.32.142:5060
From: "52880472" <sip:52880472 at 200.61.32.142>
To: <sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 101 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Contact: <sip:2003 at 200.61.32.238>
Content-Length: 0

Oct 22 09:19:51.186: Received:
SIP/2.0 183 Session Progress
Via: SIP/2.0/UDP  200.61.32.142:5060
From: "52880472" <sip:52880472 at 200.61.32.142>
To: <sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 101 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Contact: <sip:2003 at 200.61.32.238>
Content-Type: application/sdp
Content-Length: 261

v=0
o=root 20500 20500 IN IP4 200.61.32.238
s=session
c=IN IP4 200.61.32.238
t=0 0
m=audio 15664 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 19090 RTP/AVP

Oct 22 09:19:52.306: %ISDN-6-CONNECT: Interface Serial2:26 is now connected
to 5
2880474
Oct 22 09:19:52.310: Sent:
SIP/2.0 200 OK
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Date: Wed, 22 Oct 2003 09:19:49 ARBUE
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
Server: Cisco VoIP Gateway/ IOS 12.x/ SIP enabled
Contact: <sip:99952880474 at 200.61.32.142:5060;user=phone>
CSeq: 102 INVITE
Content-Type: application/sdp
Content-Length: 136

v=0
o=CiscoSystemsSIP-GW-UserAgent 7307 5758 IN IP4 200.61.32.142
s=SIP Call
c=IN IP4 200.61.32.142
t=0 0
m=audio 20130 RTP/AVP 0

Oct 22 09:19:52.310: Received:
ACK sip:99952880474 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Contact: <sip:52880472 at 200.61.32.238>
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 102 ACK
User-Agent: Asterisk PBX
Content-Length: 0

Oct 22 09:19:52.314: Received:
SIP/2.0 200 OK
Via: SIP/2.0/UDP  200.61.32.142:5060
From: "52880472" <sip:52880472 at 200.61.32.142>
To: <sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 101 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Contact: <sip:2003 at 200.61.32.238>
Content-Type: application/sdp
Content-Length: 261

v=0
o=root 20500 20500 IN IP4 200.61.32.238
s=session
c=IN IP4 200.61.32.238
t=0 0
m=audio 15664 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 19090 RTP/AVP

Oct 22 09:19:52.322: Sent:
ACK sip:2003 at 200.61.32.238:5060 SIP/2.0
Via: SIP/2.0/UDP  200.61.32.142:5060
From: "52880472" <sip:52880472 at 200.61.32.142>
To: <sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
Date: Wed, 22 Oct 2003 09:19:49 ARBUE
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
Max-Forwards: 6
Content-Type: application/sdp
Content-Length: 135
CSeq: 101 ACK

v=0
o=CiscoSystemsSIP-GW-UserAgent 624 4121 IN IP4 200.61.32.142
s=SIP Call
c=IN IP4 200.61.32.142
t=0 0
m=audio 20476 RTP/AVP 0

Oct 22 09:19:52.358: %ISDN-6-CONNECT: Interface Serial2:26 is now connected
to 5
2880474
Oct 22 09:19:52.358: %ISDN-6-CONNECT: Interface Serial2:27 is now connected
to 5
2880472
Oct 22 09:19:52.822: Received:
INVITE sip:52880472 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK5b99e531
From:
<sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
To: "52880472" <sip:52880472 at 200.61.32.142>
Contact: <sip:2003 at 200.61.32.238>
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 102 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Content-Type: application/sdp
Content-Length: 257

v=0
o=root 20500 20500 IN IP4 200.61.32.142
s=session
c=IN IP4 200.61.32.142
t=0 0
m=audio 20130 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 0 RTP/AVP

Oct 22 09:19:52.830: Sent:
SIP/2.0 200 OK
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK5b99e531
From:
<sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
To: "52880472" <sip:52880472 at 200.61.32.142>
Date: Wed, 22 Oct 2003 09:19:52 ARBUE
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
Server: Cisco VoIP Gateway/ IOS 12.x/ SIP enabled
Contact: <sip:52880472 at 200.61.32.142:5060;user=phone>
CSeq: 102 INVITE
Content-Type: application/sdp
Content-Length: 135

v=0
o=CiscoSystemsSIP-GW-UserAgent 624 4122 IN IP4 200.61.32.142
s=SIP Call
c=IN IP4 200.61.32.142
t=0 0
m=audio 20420 RTP/AVP 0

Oct 22 09:19:52.830: Received:
INVITE sip:99952880474 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Contact: <sip:52880472 at 200.61.32.238>
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 103 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Content-Type: application/sdp
Content-Length: 257

v=0
o=root 20500 20500 IN IP4 200.61.32.142
s=session
c=IN IP4 200.61.32.142
t=0 0
m=audio 20476 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 0 RTP/AVP

Oct 22 09:19:52.834: Received:
INVITE sip:52880472 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK5b99e531
From:
<sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
To: "52880472" <sip:52880472 at 200.61.32.142>
Contact: <sip:2003 at 200.61.32.238>
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 103 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Content-Type: application/sdp
Content-Length: 261

v=0
o=root 20500 20500 IN IP4 200.61.32.142
s=session
c=IN IP4 200.61.32.142
t=0 0
m=audio 20130 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 19090 RTP/AVP

Oct 22 09:19:52.842: Sent:
SIP/2.0 200 OK
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Date: Wed, 22 Oct 2003 09:19:52 ARBUE
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
Server: Cisco VoIP Gateway/ IOS 12.x/ SIP enabled
Contact: <sip:99952880474 at 200.61.32.142:5060;user=phone>
CSeq: 103 INVITE
Content-Type: application/sdp
Content-Length: 136

v=0
o=CiscoSystemsSIP-GW-UserAgent 7307 5759 IN IP4 200.61.32.142
s=SIP Call
c=IN IP4 200.61.32.142
t=0 0
m=audio 20694 RTP/AVP 0

Oct 22 09:19:52.842: Sent:
SIP/2.0 481 Invalid CSeq Number
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK5b99e531
From:
<sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
To: "52880472" <sip:52880472 at 200.61.32.142>
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 103 INVITE

Oct 22 09:19:52.846: Received:
INVITE sip:99952880474 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Contact: <sip:52880472 at 200.61.32.238>
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 104 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Content-Type: application/sdp
Content-Length: 261

v=0
o=root 20500 20500 IN IP4 200.61.32.142
s=session
c=IN IP4 200.61.32.142
t=0 0
m=audio 20476 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 12476 RTP/AVP

Oct 22 09:19:52.846: Received:
ACK sip:52880472 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK5b99e531
From:
<sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
To: "52880472" <sip:52880472 at 200.61.32.142>
Contact: <sip:2003 at 200.61.32.238>
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 102 ACK
User-Agent: Asterisk PBX
Content-Length: 0

Oct 22 09:19:52.846: Received:
INVITE sip:99952880474 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Contact: <sip:52880472 at 200.61.32.238>
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 105 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Content-Type: application/sdp
Content-Length: 261

v=0
o=root 20500 20500 IN IP4 200.61.32.142
s=session
c=IN IP4 200.61.32.142
t=0 0
m=audio 20420 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 12476 RTP/AVP

Oct 22 09:19:52.854: Sent:
SIP/2.0 481 Invalid CSeq Number
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 104 INVITE

Oct 22 09:19:52.854: Sent:
SIP/2.0 481 Invalid CSeq Number
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 105 INVITE

Oct 22 09:19:52.854: Received:
ACK sip:99952880474 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Contact: <sip:52880472 at 200.61.32.238>
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 103 ACK
User-Agent: Asterisk PBX
Content-Length: 0

Oct 22 09:19:52.858: Received:
ACK sip:52880472 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK5b99e531
From:
<sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
To: "52880472" <sip:52880472 at 200.61.32.142>
Contact: <sip:2003 at 200.61.32.238>
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 103 ACK
User-Agent: Asterisk PBX
Content-Length: 0

Oct 22 09:19:52.858: Received:
INVITE sip:52880472 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK5b99e531
From:
<sip:2003 at 200.61.32.238;user=phone;phone-context=unknown>;tag=as12560d82
To: "52880472" <sip:52880472 at 200.61.32.142>
Contact: <sip:2003 at 200.61.32.238>
Call-ID: DDEA1FF7-3C011D8-BEBEADBB-C9B38AEA at 200.61.32.142
CSeq: 104 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Content-Type: application/sdp
Content-Length: 261

v=0
o=root 20500 20500 IN IP4 200.61.32.142
s=session
c=IN IP4 200.61.32.142
t=0 0
m=audio 20694 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 19090 RTP/AVP

Oct 22 09:19:52.858: Received:
INVITE sip:99952880474 at 200.61.32.142:5060 SIP/2.0
Via: SIP/2.0/UDP 200.61.32.238:5060;branch=z9hG4bK67299947
From: "52880472" <sip:52880472 at 200.61.32.238>;tag=as7493951b
To: <sip:99952880474 at 200.61.32.142>;tag=AF869030-7
Contact: <sip:52880472 at 200.61.32.238>
Call-ID: 72a27d622d6836df2d7a7c2c21b39b14 at 200.61.32.238
CSeq: 106 INVITE
User-Agent: Asterisk PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
Content-Type: application/sdp
Content-Length: 261

v=0
o=root 20500 20500 IN IP4 200.61.32.238
s=session
c=IN IP4 200.61.32.238
t=0 0
m=audio 15740 RTP/AVP 3 0 8 101
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
m=video 12476 RTP/AVP