[OpenSER-Devel] question on t_relay on CANCEL

[Juha Heinanen]

Bogdan-Andrei Iancu writes:

 > CANCEL is only hop by hop (according to RFC 3261), so Route has no 
 > sense. If present, it will be ignore as the RFC clearly states that 
 > CANCEL must be sent to the same destination, with same VIA and RURI, as 
 > the INVITE it cancels.

this is what i think too, but i didn't find rfc 3261 very explicit about
route header(s) in CANCEL.  9.1 says:

  If the request being cancelled contains a Route header field, the CANCEL
  request MUST include that Route header field's values.

it does not say what should happen if invite doesn't include (pre-loaded)
route header, but, for example, 180 received by UAC had Record-Route
headers.

also, i haven't found in rfc 3261 a clear statement if CANCEL sent after
180, for example, is considered an in-dialog request or an initial
request.  at that point the dialog has been established already.

anyway, this question resulted when i saw that a Cisco UA to included in
CANCEL a Route header based on R-R header it received in 180.  it is
good if openser ignores such Route headers when it processes a CANCEL
that cancels an existing transaction.

-- juha