Hi Folks, As many of you probably saw, I submitted a new version of the outbound specification just before the draft deadline on Monday. There was a lot of general rewording to try to improve clarity and readability, but we received a number of contradictory suggestions, so hopefully it flow well. The major changes are:
- removed references to the 'keep' and 'timed-keepalives' parameters - added the 'Flow-Timer' header - changed the wording for the recommended timing over TCP. if battery consumption is an issue, the recommended keepalives are approximately every 14 minutes. If battery consumption is not an issue, the recommended keepalives are approximately every two minutes. - added text explaining that an edge proxy which sees an 'ob' parameter in its Route header (probably copied form the Path vector by the authoritative proxy) in a dialog-forming request, the edge proxy needs to insure that the route set will allow in-dialog requests to arrive over some valid flow to the UA instance. In the simplest cae, the edge proxy could just copy the URI (with flow token) from the Route header into the Record-Route header and delete the 'ob' parameter. If the Contact is a GRUU that should be sufficient too. If the edge proxy wants to do something fancy that even without GRUU allows mid-dialog recovery of a specific flow, that's allowed as well. - added the 439 (First Hop Lacks Outbound Support) response code - wrote a very complete example (which is hopefully correct) I hope this is satisfactory to the group. The way timers work is much simpler and more powerful and will hopefully please both server and client folks (wired and wireless alike). In addition, there was a comment on the list about using outbound with transaction stateless proxies. As it turns out, it is impossible to implement an RFC3261-compliant proxy that always operates statelessly. Implementation of TCP (and TLS over TCP) is required in RFC 3261 and when sending or receiving over TCP a proxy MUST become stateful. Based on this, I do not feel badly stating that proxies which implement outbound MUST be transaction stateful. thanks, -rohan
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