Brian and list,
Many phones support "IP direct dialing" (Linksys Sipura devices, I
think, are one example). I would expect you would find this feature most
commonly in phones that speak SIP.
SIP is an application-layer routing and negotiating protocol, and does
not participate in the RTP stream at all. Some PBX makers may get in the
middle of the stream, but that is a side effect of using SIP to route
the stream through the PBX, as I understand it.
*Most importantly, losing the central SIP routing doesn't typically
break a call in progress.* Obviously, if you lose TCP/IP routing, your
RTP packets aren't going anywhere either, but at least TCP/IP routing
doesn't have to be a single point of failure (neither does SIP actually,
so in a good deployment you aren't slave to a SPOF).
There are some other ways to map telephone "numbers" to IP addresses,
such as ENUM and DUNDi, of which DUNDi is peer-to-peer. You'll find
entries for both in Wikipedia.
I have no idea if the UF-recommended phones can do this, though a quick
search in Google suggests that they might be able to.
Martin Smith, Systems Developer
[log in to unmask]
Bureau of Economic and Business Research
University of Florida
(352) 392-0171 Ext. 221
> -----Original Message-----
> From: Platform Independent Linux List!
> [mailto:[log in to unmask]] On Behalf Of Brian Bartholomew
> Sent: Tuesday, September 11, 2007 4:21 PM
> To: [log in to unmask]
> Subject: peer-to-peer VOIP?
> The question came up at lunch:
> If you have a building full of the UF-recommended brand of VOIP phones
> on the same LAN, can they talk to each other without involving any
> additional central points of failure? I'm not asking for conference
> calls, voicemail, recordings with beeps, queues, forwarding, or
> whatever. Just using the last quad of the IP as an extension number.
> And if not, is there any alternative type of phone that can do this,
> and can also use the UF POTS gateway? Or Skype?