I think the rule of thumb is "Supported" indicates what is supported by UAC and "Require" indicates what needs to be supported by UAS (otherwise it should reject the request)
In cases like session-timer you can see that "Supported" and "Require" mean different things (because session-timer can be supported by the proxy towards either/both sides i.e it is not end to end) and in case of 100 rel "Supported" and "Require" probably mean the same thing (because it is end to end). So I would say whether an option in "Require" implicitly means it is "Supported" depends on the actual option in consideration (i.e if the option being negotiated is end to end or not) Thanks Pandu On Fri, Jun 24, 2011 at 11:04 AM, Harbhanu <harbhanu.sa...@huawei.com> wrote: > Hi, > As per 3261, the text for Supported and Require is as below- > > Supported: > If the UAC supports extensions to SIP that can be applied by the > server to the response, the UAC SHOULD include a Supported header > field in the request listing the option tags (Section 19.2) for those > extensions. > > Require: > If the UAC wishes to insist that a UAS understand an extension that > the UAC will apply to the request in order to process the request, it > MUST insert a Require header field into the request listing the > option tag for that extension. > > Is it valid to interpret that an extension present in 'Require' is also > 'Supported' by > the UAC? > In other words, is it mandatory to put an extension in both headers, incase > 'Require' is used for any extension? > This becomes bit confusing, since any Proxy 'MAY' put 'Require' in the > message. > > As per my opinion these two should be explicitly carry the extension, > because of the proxy case. > > Please share your opinion. Thanks! > > Regards, > Harbhanu > > > **************************************************************************** > *********** > This e-mail and attachments contain confidential information from HUAWEI, > which is intended only for the person or entity whose address is listed > above. Any use of the information contained herein in any way (including, > but not limited to, total or partial disclosure, reproduction, or > dissemination) by persons other than the intended recipient's) is > prohibited. If you receive this e-mail in error, please notify the sender by > phone or email immediately and delete it! > > > _______________________________________________ > 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
