[VoiceOps] TCP Signaling for SIP Signaling

[Tim Bray]

On 17/07/17 03:28, Colton Conor wrote:
> With more providers switching to encryption using TLS which uses TCP,
> is there any need for us UDP for signaling anymore? Assuming most IP
> phones from Polycom, Yealink, and Cisco support TCP why not use it? Is
> it more resouce intensive on the SBCs?

No harm keeping UDP.

It is up to service providers what they want to use.  And what works for
their customers.

I'm in favour of more TLS - it stops ALGs for sure.

>
> What about on the media side? Does the RTP use UDP or TCP? If it uses
> UDP can TCP be used? What about for encryption like SRTP? Is SRTP TCP
> or UDP?

Normal SRTP is UDP.

No reason not to run RTP over TCP. It's an option to configure in Snom
phones.   I think MS Lync might use it.

If you get packet loss, retransmits would kill delay the call.   Depends
on packetloss vs round trip time.


Tim