Dave, thanks for your comments > The correct way to look at the system starts with "What is > the Address Of Record that the endpoints will have?" They > should be something like "[EMAIL PROTECTED]", "[EMAIL PROTECTED]", etc.
yes, that's how it is in all the "textbook" examples but I don't know what domain is - there is no "domain" - just IP addresses > The "domain" part needs to route to the registrar/proxy when > the rules of RFC 3263 are applied. In the simplest cases, > that means that "domain" is either the IP address of the > registrar/proxy, or a DNS host name that maps to the IP > address of the registrar/proxy. > > Once you've settled on that, you have to arrange for each > endpoint to *a > priori* know the "domain" and its "user" (EP1, etc.). > > When the endpoint starts, it constructs the REGISTER request thusly: > > REGISTER sip:domain SIP/2.0 > To: <sip:[EMAIL PROTECTED]> > From: <sip:[EMAIL PROTECTED]> > Contact: <sip:[EMAIL PROTECTED]> > > The endpoint can now carry out RFC 3263 on "domain" to > determine where to route the message, or it can simply > forward the message to its pre- configured "outbound proxy" > (which will carry out RFC 3263 to further route the message). Question - you say it can EITHER determine where to route the message, OR fwd the message to its pre-configured "Outbound Proxy" - doesn't it have to use the Outbound Proxy IF it is configured for ALL outbound messages?? > > As you can see, as you've outlined it, it is impossible for > the endpoints to determine the "domain" to use -- it is not > constant, and there is no way to convey it to the endpoints, > because the *first* SIP message they send requires that they > know it. Conceptually, they have no idea *which* > registrar/proxy in the Internet they should be talking to. well, the location of the SIP Registrar will be constant - just not known a priori to the endpoints - would it not be feasible to get the Outbound Proxy to adjust the outbound Request-URI and fwd the message to the Registrar (if, in fact, all outbound requests have to come through it - since it knows the Registrar's IP address)? I've seen some traces of SIP traffic headers captured on the internet where the SIP REGISTER Request-URI actually contains the IP address of the originator??? - that surely doesn't seem to agree with anything I've read in RFC3261... see this Intel page for example... http://resource.intel.com/telecom/support//tnotes/tnbyos/2000/tn111/tn11 1.htm they've got an example with the request, To: and Contact: fields ALL referencing the same IP > > One way to solve this would be to add a custom extension > datum to DHCP which carries the registrar/proxy's IP address. > That might be workable if you have a closed network. wouldn't that rely on the endpoints being able to pick up on such a datum and wouldn't that be highly dependant on the implementations used by each endpoint (I'm thinking, some SIP telephones might behave very differently)? thanks again in advance to you and others for your time, patience, answers and suggestions in the meantime, I'm going to read through RFC3263 and see if that sheds any more light on any of these issues m The information contained in this e-mail message is PRIVATE. It may contain confidential information and may be legally privileged. It is intended for the exclusive use of the addressee(s). If you are not the intended recipient, you are hereby notified that any dissemination, distribution or reproduction of this communication is strictly prohibited. If the intended recipient(s) cannot be reached or if a transmission problem has occurred, please notify the sender immediately by return e-mail and destroy all copies of this message. Thank you. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
