Yealink VC120, Administrator'S Manual

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Administrator’s Guide for Yealink Video Conferencing Systems
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a=ptime:20
a=sendrecv
The callee receives the INVITE message with the RTP encryption algorithm, and then answers the
call by responding with a 200 OK message which carries the negotiated RTP encryption
algorithm.
The following is an example of the RTP encryption algorithm carried in the SDP of the 200 OK
message:
m=audio 11780 RTP/SAVP 0 101
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:NGY4OGViMDYzZjQzYTNiOTNkOWRiYzRlMjM0Yzcz
a=sendrecv
a=ptime:20
a=fmtp:101 0-15
The SRTP parameter on the system is described below:
Parameter Description Configuration Method
SRTP
Specifies the SRTP type. You can configure it
for the Zoom/Pexip/BlueJeans/Mind/Custom
platform, SIP account or SIP IP call
separately.

Disabled—
do not use SRTP in SIP calls.

Optional
—negotiate with the far site
whether to use SRTP for media
encryption in SIP calls.

Compulsory
—compulsory use SRTP for
media encryption in SIP calls.
Default:
Disabled
Note:
You cannot configure it for the
Yealink/StarLeaf Cloud platform.
Web User Interface
Rules of SRTP for media encryption in SIP calls:
Far Near Compulsory Optional Disabled
Compulsory
SRTP Call SRTP Call Fail to establish call
Optional
SRTP Call SRTP Call RTP Call
Disabled
Fail to establish call RTP Call RTP Call