Yealink VC400 Administrator's Manual page 256

Administrator's Guide for Yealink Video Conferencing Systems
When a site places a call on the SRTP enabled system, the system sends an INVITE message with
the RTP encryption algorithm to the destination system.
The following is an example of the RTP encryption algorithm carried in the SDP of the INVITE
message:
m=audio 11780 RTP/SAVP 0 8 18 9 101
a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:NzFlNTUwZDk2OGVlOTc3YzNkYTkwZWVkMTM1YWFj
a=crypto:2 AES_CM_128_HMAC_SHA1_32
inline:NzkyM2FjNzQ2ZDgxYjg0MzQwMGVmMGUxMzdmNWFm
a=crypto:3 F8_128_HMAC_SHA1_80 inline:NDliMWIzZGE1ZTAwZjA5ZGFhNjQ5YmEANTMzYzA0
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:9 G722/8000
a=fmtp:101 0-15
a=rtpmap:101 telephone-event/8000
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
SRTP
240
Description
Specifies the SRTP type. You can configure it
for the Zoom/Pexip/BlueJeans/Mind/Custom
platform, SIP account or SIP IP call
separately.
Configuration Method
Web User Interface