Call Hold Canceled

Basic Concepts

The call remains canceled, and when it is necessary to reply to the original call with a user who is in a call-hold state, the original call is canceled and the background music is stopped.

Call hold Cancel flowchart

A brief overview of call hold cancellation signaling

InThe call hold signaling mentions that the user +SendRe-inviteMessage toIpbx, you need to keep +and the1002between the calls. Re-invitemessage CarryingSDPinc=in IP40.0.0.0, stating that theRe-inviteThe message is a call hold message. While canceling the call hold is also usedRe-inviteThe only difference is that the message is done inRe-invitemessage CarryingSDPin thec=in IP4192.168.50.20values are different,192.168.50.20address is +and the1002the address between media transfers. See "Call hold Cancellation signaling" for detailed procedures.

call hold cancellation signaling

1) users send re-invite message to ipbx, need to reply to and the 1002 between the calls. the Re-invite message carries the c=in IP4192.168.50.20 in the SDP , stating that the the re-invite message is a call hold cancellation message.

INVITE sip:[email protected]:5060sip/2.0
via:sip/2.0/udp192.168.50.20:9588;branch=z9hg4bk-d8754z-da66ec3fc2251561-1---d8754z-;rport
max-forwards:70
Contact:<sip:[email protected]:9588>
To:<sip:[email protected]>;tag=54267485a
From : "<sip:[email" protected]>;tag=8c7df95e
call-id:zjbim2mxndq3zwnlm2jhyjawyweyngjlmwe4njzjymq.
Cseq:4 INVITE
Allow:invite, ACK, CANCEL, Options,bye,refer, NOTIFY, MESSAGE, SUBSCRIBE, INFO
CONTENT-TYPE:APPLICATION/SDP
supported:replaces
User-agent:bria Professional release2.4stamp 49381
content-length:238
 
v=0
O=hua 9 3 in IP4 192.168.50.20
S=counterpath Bria Professional
c=in IP4 192.168.50.20
t=0 0
M=audio 7624 RTP/AVP 0 101
a=fmtp:101 0-15
a=rtpmap:101 telephone-event/8000
a=sendonly
A=x-rtp-session-id:84405823042846cfa4f793eb20feb7e6

2) IPBX received Re-invite request response, reply to users between 1000 and 1002 of the call, and stop giving the user 1002 play background music, to the user 1000 reply confirmation message.

sip/2.0 OK
Via:sip/2.0/udp192.168.50.20:9588;branch=z9hg4bk-d8754z-da66ec3fc2251561-1---D8754z-;rport
From: "<sip:[email" protected]>;tag=8c7df95e
To:<sip:[email protected]>;tag=54267485a
Call-id:zjbim2mxndq3zwnlm2jhyjawyweyngjlmwe4njzjymq.
Cseq:4 INVITE
User-agent:freeswitch
Contact:<sip:[email protected]:5060>
Content-type:application/sdp
content-length:201

V=0
O=session 1639146064 1639146065 INIP4192.168.50.22
S=play
C=in IP4 192.168.50.22
T=0 0
M=audio 10476 RTP/AVP 0 101
a=rtpmap:0 pcmu/8000
A=rtpmap:101 telephone-event/8000
A=fmtp:101 0-16

3) User 1000 received IPBX send acknowledgement request message 200OK, send ACK message to Ipbxack sip:[email protected]:5060 sip/2.0

Via:sip/2.0/udp192.168.50.20:9588;branch=z9hg4bk-d8754z-ef0e4b7cfe6a7548-1---D8754z-;rport
Max-forwards:70
Contact:<sip:[email protected]:9588>
To:<sip:[email protected]>;tag=54267485a
From: "<sip:[email" protected]>;tag=8c7df95e
Call-id:zjbim2mxndq3zwnlm2jhyjawyweyngjlmwe4njzjymq.
Cseq:4 ACK
User-agent:bria Professional Release2.4stamp 49381
content-length:0

Note: in the SDPc=in IP4 192.168.50.20The address used to establish the transfer between media. Address0.0.0.0Indicates that the end does not accept any media, and when the media is accepted again, bring the valid address accepted by the media.

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

Call Hold Canceled