Yealink SIP-T2xP Administrator's Manual page 245

2. Select the desired value from the pull-down list of Device Certificates.
3. Click Confirm to accept the change.
To upload a server certificate via web user interface:
1. Click on Security->Server Certificates.
2. Click Browse to select the certificate (*.pem and *.cer) from your local system.
3. Click Upload to upload the certificate.
A dialog box pops up to prompt "Success: The Server Certificate has been loaded!
Rebooting, please wait...".
Secure Real-Time Transport Protocol (SRTP) encrypts the RTP streams during VoIP
phone calls to avoid interception and eavesdropping. The parties participating in the
call must enable SRTP feature simultaneously. When this feature is enabled on both
phones, the type of encryption to utilize for the session is negotiated between the IP
phones. This negotiation process is compliant with RFC 4568.
When a user places a call on the enabled SRTP phone, the IP phone sends an INVITE
message with the RTP encryption algorithm to the destination phone.
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
Configuring Security Features
229