[sr-dev] RFC 5626 (Outbound) planned?

[Juha Heinanen]

Olle E. Johansson writes:

> The main difference compared with RFC 3261 is that the burden of
> connection management - UDP, TCP or STCP - is put on the UA.
> The proxy reuse the connection created by the UA for outbound
> requests, but does NOT open new connections.

there is no difference to what my proxy does today.  it does not try to
setup tcp connections to ua (set_forward_no_connect()) and udp is a bad
idea anyway.

> The specification also adds the ability, but not the requirement,
> to handle multiple connections (flows) from the same UA to different proxys 
> as failover connections. This will indeed make TCP failover faster and
> propably SHOULD be a requirement for TCP/TLS.

yes, but since it is NOT a requirement, you don't get any benefit.

> Previously it was impossible to 
> recognize that multiple registrations was from the same UA, so the proxy
> had to fork to all of them and just hope that the UA had some merged fork
> detection.

this is indeed an improvement as i have already mentioned and very easy
to implement in the ua.  baresip, for example, does add +sip.instance
param to contact header:

REGISTER sip:test.fi SIP/2.0.
Via: SIP/2.0/TCP 188.67.205.145:35327;branch=z9hG4bKfa4a89e63adaf759;rport.
Contact: <sip:jh at 188.67.205.145:35327;transport=tcp>;expires=600;+sip.instance="<urn:uuid:c79b8de4-6c2f-4d48-a347-d13d9b19d255>".

but does not add Supported: gruu in requests.

so my suggestion is to put priority in adding +sip.instance support to
sr registrar/usrloc implementation.

-- juha