[impdev] Upcoming changes to SL group chat protocol

[Jacek Antonelli]

Oz Linden held a meeting with TPV developers today, to discuss
upcoming changes to group chat on SL. Squire Linden talked about their
plans to replace their home-grown group chat system with XMPP in the
future. It's still very early in the process, so this is advanced
notice. There will be a (temporary) bridge so that viewers using the
old protocol will still be able to use group chat, but eventually
(long term) the old group chat system will be switched off entirely.

My impression is that this is not something we need to be concerned
about. We will be switched over to the 2.x code base long before the
old service is shut down, so it won't be difficult to merge in the new
protocol. I don't imagine it would be too hard to also keep in support
for the old group chat, for use on OpenSim. I'm not sure it would be
worthwhile to do another release of the old codebase when the new
service rolls out, but we can consider it at that time.

Below are the (hastily assembled, ungrammatical) notes I made during
the meeting. Oz is going to post the chat transcript and voice
recording somewhere, but I don't have a link at the moment.

- Jacek

-----

LL will set up cluster of XMPP servers that viewer will talk to
directly (most likely visible via a CAP). Will get viewer code out
early on so TPVs can backport it. Will have technical/protocol
documentation on wiki too.

LL will most likely set up a "bridge" to support old viewers that are
still using the old protocol. But the chat performance with the bridge
probably won't be as good as native XMPP. Leaning towards leaving sim
as it is, implementing a replacement chat service for the bridge. LL's
general direction is to separate things from the sim into other
services.

LL is pushing to release a 'project viewer' (prototype/focused on one
project) with source by the end of the year, but schedule may change.
Bridge will come later. Project viewer will only support XMPP, for
testing, not a good idea for TPVs to use that code for production
viewers.

Bridge will be temporary, for transition purposes. Old group chat
protocol will be deprecated and some day disabled. No time table for
that yet, but there will be plenty of advance notice.

LL would like to open up the XMPP servers to other (non-viewer)
clients in the future, but is not top priority now. They are bearing
that it in mind as they design the system, e.g. how to do
authentication.

Good possibility of raising group number limit once XMPP is in place.
One issue they are investigating is how very large groups (tens of
thousands of users) are used (or not used) for actual real-time chat,
or more like advertising or broadcasted announcements (which don't
need to be exactly real-time). May investigate other group issues
later (e.g. land groups that don't need chat).

Once the XMPP infrastructure is up, they may investigate using it for
other things (e.g. presence, group notices) in the future.

Rough guesstimate timeline: project viewer by end of year or early
next year, bridge in March or April maybe. No timeline yet for
disabling the old group chat service.