Re: [tram] STUNBIS: Retransmissions over TCP

[Simon Perreault <[e-mail]>]

Le 2016-07-26 à 05:23, Olle E. Johansson a écrit :
> Section 6.2.2:
> 
> "Reliability of STUN over TCP and TLS-over-TCP is handled by TCP
>    itself, and there are no retransmissions at the STUN protocol level.”
> 
> When using STUN over mobile networks, I think this is a bad assumption.
> We’ve seen many times that TCP proxys cause TCP to fail and they don’t follow
> the original intention of TCP. The SIP message fails, even though TCP confirmed
> delivery. I’ve got confirmation from a few developers that they started to send UDP-style
> retransmits over TCP to get around this.

I think this will be met with incredulity and responses along the lines
of "pcap or GTFO". :)

I admit I'd like to see a more detailed description of the problem
before we mandate such a profound change in the protocol. Would you be
able to get one of those developers to come talk to us?

> As a discovery protocol, I think we need STUN to discover situations like this.
> I know it’s not religiously correct, but retransmits over TCP unfortunately makes sense 
> in today’s broken network, especially for a protocol designed to discover middle boxes.

To be clear: you actually mean sending a second Binding request on the
*same* TCP connection, right? Not opening a new one?

Simon