Hi Holi The RFC says UAS should add a Require: timer in response when UAC is the refresher to indicate to UAC that it is the refresher. But I think this is redundant as UAC anyway knows it is the refresher and does not need a reminder from UAS.
On Fri, May 28, 2021 at 3:18 PM Hoil Choi <hoil.c...@hotmail.com> wrote: > Hi Ranjit, thanks for taking a look. > > However, I'm more interested in case where UAS is responding to UAC's > request with refresher as itself (uac). Consider this case - > > UAC ---- INVITE (Session-Expires: 1800;refresher=uac, Supported: timer) > ----> UAS > UAC <---- 200 OK (Session-Expires: 1800;refresher=uac) > --------------------- UAS > > In this case, the statement in question seems to convey that UAS should > also add "Require: timer" in its 200 response. Why would this be, when > it's clear that UAC declared itself as the refresher and that timer is > supported? > > For reference, RFC 4028 Section 9 UAS Behavior (or page 16) > If the refresher parameter in the Session-Expires header field in the 2xx > response has a value of 'uac', the UAS MUST place a Require header field > into the response with the value 'timer'. > > Thanks, > Hoil > > ------------------------------ > *From:* Ranjit Avasarala <ranjitka...@gmail.com> > *Sent:* Friday, May 28, 2021 12:38 PM > *To:* Hoil Choi <hoil.c...@hotmail.com>; > Sip-implementors@lists.cs.columbia.edu < > Sip-implementors@lists.cs.columbia.edu> > *Cc:* sipc...@ietf.org <sipc...@ietf.org> > *Subject:* Re: [sipcore] RFC 4028 UAS behavior requirement of Require > header > > Hi Holi > the presence of the "Require" header with value "timer" from UAS indicates > to UAC that it (UAC) is performing the refreshing operation. but if the UAS > is the refresher, then if Require header with value "timer" is present in > response from UAS, then UAC should send BYE if it does not receive a > session refresh request from UAS. > > Regards > Ranjit > > > > On Fri, May 28, 2021 at 10:02 AM Hoil Choi <hoil.c...@hotmail.com> wrote: > > Hello, > > I hope this mail finds appropriate person or team for an answer to my > question on RFC 4028. > I am a SIP enthusiast and always learning a lot about it, but by no means > am I an expert; so please excuse my ignorance. > > I came across an interesting statement In Section 9 UAS Behavior (or page > 16). > > > If the refresher parameter in the Session-Expires header field in the > 2xx response has a value of 'uac', the UAS MUST place a Require > header field into the response with the value 'timer'. > > > Statement seems to convey that UAS must place a Require header with value > 'timer' when UAC requests itself to be the refresher. > > However, this statement should only be true, if UAC did not put > Session-Expire with value of 'uac'. > > If UAC, in INVITE request, put Session-Expire with value of 'uac' > (itself), UAS should not bother putting Require header field in the > response. Or to be more accurate, UAC should include 'timer' in Supported > header, so that UAS doesn't have to bother putting Require header field. > > What is the reason behind the requirement of Require header, from UAS in > this case? > > Thanks! > Hoil Choi > 253-273-5442 > > _______________________________________________ > sipcore mailing list > sipc...@ietf.org > https://www.ietf.org/mailman/listinfo/sipcore > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ietf.org%2Fmailman%2Flistinfo%2Fsipcore&data=04%7C01%7C%7C4f68f91aa77847f0fb6508d922102eb4%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637578275155641932%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=3McfrKwjz9RwC%2FBRLtdyopgzmNmUqsAKdAXyyRvChuc%3D&reserved=0> > > _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
