Jeroen, Yes, this is effectively what you have when an IPPBX is required to register with a service provider. But in that case, there might also be a need to implement sip-outbound if there are unadministered NATs/firewalls in the way. Indeed, sip-outbound would operate between a virtual UA on the IPPBX side and a registrar on the service provider side.
What I am interested in gaining from this discussion is whether there are proxy-to-proxy cases where sip-outbound is not appropriate but keep-alive (or heartbeat) is needed. John > -----Original Message----- > From: Jeroen van Bemmel [mailto:[EMAIL PROTECTED] > Sent: 25 June 2008 22:56 > To: Christer Holmberg > Cc: Hadriel Kaplan; [EMAIL PROTECTED]; Elwell, John; > [EMAIL PROTECTED]; [email protected] > Subject: Re: [Sip] Progress draft-holmberg-sip-keep: > proxy-to-proxy use case > > No, not a B2BUA. Each element would have a virtual UA function "in > parallel" to its regular function (e.g. being a proxy). And > indeed, one > way to implement this would be to keep either one (one way) or two > (opposite ways) flows active between them. > > Like so: > > |-----------| |-----------| > | Proxy | | Proxy | > |-----------| |-----------| > | UA | <---------->| UA | > |-----------| |-----------| > > Each "UA" would implement both a simple registrar and a UAC > performing > registration. It could also be setup asymmetrically, with the > (smaller) > IP-PBX doing a single registration towards the (bigger) > Service provider > network. Registration expiry would denote a loss of connectivity. > > Regards, > Jeroen > > > Christer Holmberg wrote: > > Hi, > > > > So, you are proposing that each element should be a B2BUA, > and both elements then register towards each other and use Outbound??? > > > > Regards, > > > > Christer > > > > -----Original Message----- > > From: Jeroen van Bemmel [mailto:[EMAIL PROTECTED] > > Sent: 25. kesäkuuta 2008 22:57 > > To: Hadriel Kaplan > > Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]; > [EMAIL PROTECTED]; [email protected]; Christer Holmberg > > Subject: Re: [Sip] Progress draft-holmberg-sip-keep: > proxy-to-proxy use case > > > > Hadriel, Markus, > > > > Instead of standardizing keep-alives between proxies, how > about we define a "virtual UA" on each element (similar to > the one described in > > RFC3261 section 16.7 point 6) to be used to provide this > functionality? > > (using existing outbound functionality, perhaps both ways) > > > > Regards, > > Jeroen > > > > Hadriel Kaplan wrote: > > > >> Yes I am of that same opinion - that any real "IP-PBX" or > whatever big > >> enough NOT to be doing Registration, and to instead do > static provisioning or DNS, would be given a static hole/DMZ > address in their firewall/NAT. But some of my customers have > told me otherwise. (interestingly mostly in APAC region) > There's also some concern that while a static entry is there > for inbound TCP connections, the PBX creates outbound ones to > the service provider which are ephemeral port sources and > need to live for very long durations (though why they can't > just do TCP keepalive is beyond me, but I'm no expert). > >> > >> But anyway, the big issue we've seen is that we need both > the PBX and the service provider box to detect failure before > an active call/request attempt is made; to trigger alternate > route selection without waiting for transport failure, and as > a method to detect liveness again and revert. Today that's > almost exclusively done with Options requests as far as I've > seen, and lots of people don't seem to like that. > >> > >> -hadriel > >> > >> > >> > >> > >>> -----Original Message----- > >>> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > >>> Sent: Wednesday, June 25, 2008 3:11 PM > >>> To: [EMAIL PROTECTED]; Hadriel Kaplan; > >>> [EMAIL PROTECTED]; [email protected] > >>> Cc: [EMAIL PROTECTED] > >>> Subject: RE: [Sip] Progress draft-holmberg-sip-keep: > proxy-to-proxy > >>> use case > >>> > >>> Hi, > >>> > >>> I'm a bit sceptical about the need for keep-alives > between proxies. > >>> It is of course entirely possible that an enterprise PBX > is connected > >>> to (or peering with) a service provider proxy through a > NAT and/or a > >>> firewall. However, wouldn't such a NAT or firewall be under the > >>> administration of either the enterprise itself or its ISP > (who quite > >>> often would be the SIP service provider), and the required port > >>> forwardings or firewall rules could be set through > administration. > >>> This means that there would not be need for keepalive traffic to > >>> implicitely keep the mapping/pinhole open. > >>> > >>> Or are there really deployment cases where there are SIP > PBXs behind > >>> unadministrated NATs or firewalls? > >>> > >>> Wouldn't we then need keepalives for SMTP as well, or how has the > >>> e-mail infrastructure managed to solve this problem? > >>> > >>> Markus > >>> > >>> > >>> > >> _______________________________________________ > >> Sip mailing list https://www.ietf.org/mailman/listinfo/sip > >> This list is for NEW development of the core SIP Protocol Use > >> [EMAIL PROTECTED] for questions on current sip Use > >> [EMAIL PROTECTED] for new developments on the application of sip > >> > >> > >> > > > > > _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
