mesh portal discovery

[Morgan Collett]

Simon McVittie wrote:
> On Wed, 09 Jan 2008 at 22:17:18 -0500, John Watlington wrote:
>> We have a presence service which
>> provides a way for P2P applications to find
>> one another, even after the IP changes.
> 
> Presence Service isn't magical. If a laptop's IP address changes, in the
> link-local backend (Salut) this will most likely appear as a disconnect +
> reconnect (and the user will leave all shared activities they were currently
> in). This is somewhat unavoidable, but if it's a hard requirement that Salut
> do its best to survive IP addresses changing, file a bug against
> telepathy-salut.
> 
> In the server-based backend, an IP address change *will* cause a
> disconnect and reconnect. This is definitely unavoidable, since XMPP
> uses a long-lived TCP connection to the server.

As mentioned in #5620, activities aren't "aware" of the dropped
connection, and still show "shared" in the sharing combobox. We don't
yet have a (standard) way for activities to detect the disconnection and
handle it gracefully. So "user will leave all shared activities" means
the activities keep running with no indication to the user that
disconnection occurred, except that sharing stops working...

Morgan