Yealink SIP-T27P [711/841] Procedure

Configuring Security Features

695

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.

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 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

Procedure

SRTP can be configured using the configuration files or locally.

Configuration File

<MAC>.cfg

Configure SRTP feature on a

per-line basis.

Parameter:

account.X.srtp_encryption

Local

Web User Interface

Configure SRTP feature on a

per-line basis.

Navigate to:

http://<phoneIPAddress>/servl

et?p=account-adv&q=load&ac

c=0

Details of the Configuration Parameter:

Parameters

Permitted Values

Default

account.X.srtp_encryption

0, 1 or 2

If you enable SRTP, then you should also enable TLS. This ensures the security of SRTP

encryption. For more information on TLS, refer to Transport Layer Security on page 684.