We support both TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) communication protocols. While UDP is by far the most common of the two protocols TCP is stated to have advantages.
- Keep Alives: SIP must periodically send out keep-alives to maintain the NAT table entry. The required frequency of keep-alives is much higher for UDP (maybe every 30 seconds) vs TCP (maybe every 15 minutes). While not relevant for small installations TCP has significant advantages within enterprise installations.
- TLS: In a security conscious world TCP enables your end points with Transport Layer Security (TLS) which over the separate port 5061 instead of the normal 5060 for UDP.
- SRTP (Secure Real-Time Transport Protocol or Secure RTP): SRTP encrypts or “codes” the voice data itself so that no one can understand what is being said except the person who has the decoding “key”, or the person to whom the call is being made. SRTP and SIP TLS encrypt different parts of the VoIP service but together security conscious organisations such as financial or military to use this service.
Step One: TCP, TLS & Secure RTP Options
- Log into https://now.tel2.co.uk > select number you wish to set up remote call back on.
- Select CloudPBX > Advance > TCP, TLS & Secure RTP Options.
- Select one of the SIP Transport options.
- Enable Secure Encrypted RTP
- Click Save settings to update
Step Two: Change PBX/handset transport
- Log into IP PBX / Handset
- Select Account
- Find option to change Transport > TLS