Maybe not that usual, but it is used in some solutions for "implicit registration groups". The problem is of course that we can't place an explicit contact in the REQ-URI, with IP-address and port. I think there is something going on at 3gpp in this area.
/John Aronsson -----Ursprungligt meddelande----- Från: Raj Jain [mailto:[EMAIL PROTECTED] Skickat: den 9 januari 2008 00:47 Till: 'John Aronsson'; [email protected] Ämne: RE: [Sip-implementors] Using domain names in Contact URI > Of course you can use a username and a FQDN in the contact. True, as far as the SIP ABNF goes. I guess, I found it a bit unusual to use FQDNs in Contact (and as an analogy in Via). These headers are meant to identify an actual device. Are there any examples of systems where FQDNs are used in Contact? With Via, at least we have the received= parameter so we don't need to do a DNS lookup when it comes to delivering a response. However, if the Contact contains an FQDN then the UAC/Proxy will need to do a DNS (RFC 3263) lookup do deliver a request to the UAS. This could result in a mid-dialog request being routed to a whole different device than what the AoR wanted. -- Raj > Without it, i.e. using IP-addresses, proxies would be quite > handicapped. > > Let me quote 3261: > > > "The location service is just an abstract concept. It generally > contains information that allows a proxy to input a URI > and receive a > set of zero or more URIs that tell the proxy where to send the > request. Registrations are one way to create this information, but > not the only way. Arbitrary mapping functions can be configured at > the discretion of the administrator. > > Finally, it is important to note that in SIP, registration is used > for routing incoming SIP requests and has no role in authorizing > outgoing requests. Authorization and authentication are handled in > SIP either on a request-by-request basis with a challenge/response > mechanism, or by using a lower layer scheme as discussed in Section > 26." > > But, I have a feeling You're after something else, but don't > know what :-) > > John Aronsson > > -----Ursprungligt meddelande----- > Från: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] För Raj Jain > Skickat: den 7 januari 2008 20:50 > Till: [EMAIL PROTECTED] > Kopia: [email protected] > Ämne: Re: [Sip-implementors] Using domain names in Contact URI > > On Jan 7, 2008 1:54 PM, <[EMAIL PROTECTED]> wrote: > > I'm not sure whether it makes to sense to use domain names in a > > Contact URI. The SIP ABNF allows it. Any thoughts or > suggestions on > > this? > > > > It is legal to do so, and it is mandatory that a registrar/proxy > > support it correctly, as the registrar does not control the contact > > addresses that UAs will present to it. > > Define "support it correctly". If my Registrar uses its own > database to resolve a domain name in a Contact URI instead of > querying DNS, then am I violating any normative statements > made in any RFC? > > > I don't know what the constraints in your design are, but have you > > considered using a URI-parameter? If your redirection > service carries > > the URI-parameter form the AOR to the registered contact, > then you can > > have an unlimited number of different SIP URIs that map through one > > registration to distinct contact URIs. > > Let me try to understand this. We didn't really have a > redirection service in mind. We were thinking that a > Registrar and a Proxy will be sufficient. Our goal is to bind > hundreds of Contact URIs to one AoR. > We're saying that we can't carry all those Contact URIs > in-line in a REGISTER message so lets carry them "indirectly" > and use an OOB mechanism. I'm not sure how a Redirection > Service, URI parameter helps this situation. > > -- > Thanks, > Raj > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
