Specifications

Administrator’s Guide for SIP-T46G IP Phone
200
a=rtpmap:101 telephone-event/8000
a=ptime:20
a=sendrecv
The callee receives the INVITE message with the RTP encryption algorithm. The callee
answers the call and responses with a 200 OK message carrying the negotiated RTP
encryption algorithm.
The example of the RTP encryption algorithm carried in the SDP of the 200 OK
message for reference:
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
You can configure the SRTP feature on a per-account basis. When SRTP is enabled on
both IP phones, the RTP streams will be encrypted, and a lock icon appears on the
LCD screen of each IP phone after the successful negotiation.
Note
Procedure
SRTP can be configured using the configuration files or locally.
Configuration File
<MAC>.cfg
Configure the SRTP feature on a
per-account basis.
For more information, refer to
SRTP on page 342.
Local
Web User Interface
Configure the SRTP feature on a
per-account basis.
Navigate to:
http://<phoneIPAddress>/servlet
?p=account-adv&q=load&acc=
0
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 193 .