comments inline... On Wed, Apr 11, 2012 at 9:36 AM, SHARATH CHANDRA B <sharat...@huawei.com>wrote:
> 2) IN-DIALOG-1 = INVITE, IN-DIALOG-2 = INVITE > >> > >> What should reply bob for the second INVITE? > > [Query] regarding UAS Sending 491 response in the above mentioned scenario. > > 21.4.27 491 Request Pending > > The request was received by a UAS that had a pending request within > the same dialog. Section 14.2 describes how such "glare" situations > are resolved. > > As per rfc 3261 section 21.4.27 does it mean that 491 response is sent only > for glare situation or it can be sent in a situation where UAS had pending > request within the same dialog. > [ABN] Yes, the 491 response has been defined for usage with glare conditions. RFC6337, sec 4.2 lists out some scenarios where 491 response can be used. ***it can be sent in a situation where UAS had pending request within the same dialog*** <3261, sec 14.2> A UAS that receives a second INVITE before it sends the final response to a first INVITE with a lower CSeq sequence number on the same dialog MUST return a 500 (Server Internal Error) response to the second INVITE and MUST include a Retry-After header field with a randomly chosen value of between 0 and 10 seconds. </3261> [ABN] since rfc3261, sec 14.2 explicitly suggests to use 500 for this scenario, 491 can't be used. If this statement was not in the 3261, then we could have thought of using 491 with retry-after header for handling 2nd re-INVITE, while 1st re-INVITE still in transient state. This is my personal opinion.... > Thanks & regards > Sharath > > -----Original Message----- > From: sip-implementors-boun...@lists.cs.columbia.edu > [mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Paul > Kyzivat > Sent: Tuesday, April 10, 2012 9:10 PM > To: sip-implementors@lists.cs.columbia.edu > Subject: Re: [Sip-implementors] Is it allowed to send an in-dialog request > while a previous in-dialog request (in same direction) has no final > response? > > On 4/10/12 11:25 AM, Nataraju A.B wrote: > > >> 2) IN-DIALOG-1 = INVITE, IN-DIALOG-2 = INVITE > >> > >> What should reply bob for the second INVITE? > >> > > [ABN] this is an incorrect behavior from UAC. because this (2nd INVITE) > > lead to overlapped offer-answer request. In this case it is expected that > > UAS reply with 491 Request pending. > > Its incorrect, but not for that reason. According to 3261 section 14.1: > > Note that a UAC MUST NOT initiate a new INVITE transaction within a > dialog while another INVITE transaction is in progress in either > direction. > > The proper response to use in this case is open to discussion. 491 > doesn't seem like the right response - it is for glare (requests in > opposite directions). In the absence of a better choice I think probably > 400 applies. (But I wouldn't get too upset with an implementation that > chose some other 4xx, including 491.) > > Thanks, > Paul > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@lists.cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@lists.cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > -- Thanks, Nataraju A.B. +91-98455-95744 _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
