[OpenSIPS-Users] Linksys SPA-942 BLF and OpenSIPS presence

Iñaki Baz Castillo ibc at aliax.net
Wed May 27 10:52:02 CEST 2009

2009/5/27 James Lamanna <jlamanna at gmail.com>:
> Hi,
> Has anyone been able to get the BLF to work with a SPA-942 and the
> OpenSIPS presence module?

There are many types of "presence":

- Presence SIMPLE (user status: online, offline, away, on-meeting...)
=> "Event: presence"
- Presence BLF (RFC 4235): line status (calling, on-call, idle...) =>
"Event: dialog"

Asterisk supports **very poorly and wrongly** the BLF presence (but it
does it VERY VERY wrongly, in a propietary way instead of following
the RFC 4235. Linksys phones allos this painful "Asterisk BLF

OpenSIPS presence module is generic, it allows any kind of presence,
but "somebody" must send the PUBLISH with the user or line status.
Users implementing SIMPLE presence (X-Lite, Eyebeam, Twinkle,
Ekiga...) send PUBLISH ("Event: presence") by themself, they arrive to
the presence server (Opensips presence module) and it generates NOTIFY
for subscribers.

In case of BLF, "something" should send PUBLISH "Event: dialog" when a
call occurs (in progress, established...). A phone couuld do it, but
it's not very usual. However OpenSIPS has a module called
"pua_dialoginfo" which generates PUBLISH "Event: dialog" when an
INVITE occurs. I've tested it and didn't seem robust for me. Read the
documentation about it.

> There must be something different from the BLF responses from an
> Asterisk server and from OpenSIPS,
> because the BLF works great when the phone is monitoring the Asterisk
> server directly.
> I can see the SUBSCRIBE and the NOTIFY messages coming through, so
> maybe the phone just doesn't
> understand the NOTIFYs?

Presence is more complex that what you suggest. There are different
kinds of presence packages.


Iñaki Baz Castillo
<ibc at aliax.net>

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