Yealink SIP-T4X Administration Manual page 225

Administrator's Guide for SIP-T4X IP Phones
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.
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
SRTP feature is configurable on a per-line basis. When SRTP is enabled on both IP
phones, RTP streams will be encrypted, and a lock icon appears on the LCD screen of
each IP phone after successful negotiation.
Note
If you enable SRTP , then you should also enable TLS. This ensures the security of SRTP
encryption. For more information on TLS, refer to
Procedure
SRTP can be configured using the configuration files or locally.
Configuration File
Local
To configure SRTP via web user interface:
1. Click on Account.
2. Select the desired account from the pull-down list of Account.
3. Click on Advanced.
210
Transport Layer Security
<MAC>.cfg
Web User Interface
on page 203.
Configure SRTP feature on a
per-line basis.
For more information, refer to
SRTP on page 369.
Configure SRTP feature on a
per-line basis.
Navigate to:
http://<phoneIPAddress>/servlet
?p=account-adv&q=load&acc=
0