Subject: [Stox] Stox-media: Should XEP-176 translations have Require: ice?

From: Jonathan Lennox <[email-masked]>
Date: Thu, 9 Jan 2014 17:31:12 +0000

I was thinking about the issue that unlike RFC 5245, XEP-176's definition of ICE doesn't support fallback to a non-ICE mode.

It occurred to me that SIP has a way of saying "do ICE, or fail the call": putting a "Require: ice" SIP option tag (from RFC 5768) in the SIP INVITE.

Should we recommend this?  It clearly has the right semantics, and will prevent interop failure when a non-ICE SIP endpoint answers a XEP-176 Jingle call.

My concern, though, is whether there are a) endpoints that implement RFC 5245 but not RFC 5768, or b) non-media-terminating B2BUAs that will pass ICE parameters through, but will reject calls with Require headers they don't know.  In either of these cases, adding this Require header would cause a call that would otherwise have worked to fail.

Any thoughts, especially from folks who know the state of deployed SIP better than I do?