[Pkg-telepathy-maintainers] Bug#704234: Bug#704234: upstream comments

[Simon McVittie]

On 30/03/13 09:13, Daniel Pocock wrote:
> This post in the upstream discussion list seems to confirm what has been
> observed[1], they are hardcoding Google server details into the call setup

The details discussed in that email are only the case for Google
accounts (GMail, "Google Apps For Your Domain" or similar) - notice that
the user in the quoted XML is user at gmail.com, and is sending a request
"to themselves", which is processed on their behalf by their own "home"
server, in this case gmail.com. Ordinary XMPP servers don't support the
google:jingleinfo extension, so we don't use it.

Strictly speaking, if a third-party XMPP service advertised support for
Google's google:jingleinfo extension, I suppose they could send back
details of their own TURN servers in the same way, and a token which can
be used to open sessions on their TURN servers via the same HTTP
requests used for Google's TURN servers. I'm not aware of any server
that actually does this.

I don't think there's a standard way to do the equivalent of
google:jingleinfo yet: service location could just be DNS SRV or
something, but the harder part is exchanging credentials to ensure that
only authorized XMPP users can use the TURN server, because TURN is
bandwidth-expensive.

> It also suggests that there is a dependency on the Google
> infrastructure, if Google changes it, then Empathy breaks.

TURN servers are used when either the telepathy-gabble user or their
peer has a Google account, and even then, only when STUN fails to
establish a connection: on a "friendly" network like a typical domestic
NAT, they won't be needed. If Google change their API for TURN, Google
accounts will regress to behaving like non-Google accounts do now.

    S