[sipcore] 199 issue: UAC issue when proxies send unreliable 199 in case of Require:100rel

[Christer Holmberg <[e-mail]>]

Hi,

An issue that came up during the review of 199 was whether the fact that a proxy was allowed to send unreliable 199 responses, even in the case of Require:100rel.

The WG previously agreed that Require:100rel as such does not affect proxies. But, the issue that has been raised is more related to the UAC: it could receive unreliable 199 responses even if it has required provisional responses to be sent reliably.

So, people asked whether we would need to update RFC 3262, and state that a UAC has to be ready to receive unreliable provisional responses even in the case of Require:100rel.

Another proposal was so simply say that a proxy is not allowed to send 199 responses in case of Require:100rel, and include a recommendation that the UAC does not use Require:100rel when also indicating support of 199 - unless the UAC also uses other extensions that mandates Require:100rel, that is.

My suggestion is to move forward with the second proposal, i.e. to say that a proxy must not send 199 responses in case of Require:100rel.

If someone objects to such way forward, please indicate it on the list (preferable together with an alternative solution) by Friday this week.

Thanks!

Regards,

Christer