Matthew Gardiner wrote: > > I was not aware that REFER could create a dialog aswell. I have briefly > come across REFER before, though this was in the context of facilitating > call transfer in SIP.
> I have now (very quickly) skimmed over RFC 3515 to confirm this dialog > creation property. However, I now feel a little puzzled: there seems to > be very little difference in purpose behind the SUBSCRIBE and the REFER > method; both seem to request notifications in change of some state > information. You are right that they both request notifications, but I think you are missing the point about REFER. It actually tries to cause something to happen (e.g. make one endpoint call another). The notifications are an extra, to make monitoring the process more straightforward (the real problems appear to come if the REFER request is forked...) There is ongoing work in the SIP wg concerning this draft: draft-ietf-sip-refer-with-norefersub-04.txt which (in a nutshell), allows you to send a REFER without making the implicit subscription. You might find the draft helpful in understanding the differences. Regards, Michael _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
