[Serusers] [Serdev] loose_route behaviour, detecting single Route with myself
Martin Hoffmann
hn at nvnc.de
Mon Jul 16 14:33:01 CEST 2007
Jan Janak wrote:
> Martin Hoffmann wrote:
> > Klaus Darilion wrote:
> >> sl:
> >> (A) loose_route=true, --> just forward
> >> (B) loose_route=false, --> lookup()*, forward
> >> (C) loose_route=true, --> just forward
> >> (D) loose_route=true, --> lookup()**, forward
> >
> > Just a quick reminder that lookup() and forward don't go together. A
> > stateless proxy has to make the same decision for the same message (aka
> > re-sent request). Since entries in usrloc expire, there is a good chance
> > that a resent will be send somewhere else.
>
> What makes you think that stateless proxies have to make the same
> decision for the same message?
RFC 3261, section 16.11:
| A stateless proxy MUST follow the request processing steps described
| in Sections 16.4 through 16.5 with the following exception:
|
| o A stateless proxy MUST choose one and only one target from the
| target set. This choice MUST only rely on fields in the
| message and time-invariant properties of the server. In
| particular, a retransmitted request MUST be forwarded to the
| same destination each time it is processed. Furthermore,
| CANCEL and non-Routed ACK requests MUST generate the same
| choice as their associated INVITE.
> You paragraph would make sense for stateful proxies for the duration
> of the transaction.
Well, no, since a stateful proxy makes the decision only once per
transaction (it swallows re-sent messages).
Regards,
Martin
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