[sip-overload] draft-ietf-soc-overload-control-02

["DRAGE, Keith (Keith)" <[e-mail]>]

OK so you asked me to look at section 12 in the soc meeting and I have done so.

12.  100-Trying provisional response and overload control  parameters

   The overload control information sent from a SIP server to a client
   is transported in the responses.  While implementations can insert
   overload control information in any response, special attention
   should be accorded to overload control information transported in a
   100-Trying response.

   Traditionally, the 100-Trying response has been used in SIP to quench
   retransmissions.  In some implementations, the 100-Trying message may
   not be generated by the transaction user (TU) nor consumed by the TU.
   In these implementations, the 100-Trying response is generated at the
   transaction layer and sent to the upstream SIP client.  At the
   receiving SIP client, the 100-Trying is consumed at the transaction
   layer by inhibiting the retransmission of the corresponding request.
   Consequently, implementations that insert overload control
   information in the 100-Trying cannot assume that the upstream SIP
   client passed the overload control information in the 100-Trying to
   their corresponding TU.  For this reason, implementations that insert
   overload control information in the 100-Trying MUST re-insert the
   same (or updated) overload control information in the first non-100
   response being sent to the upstream SIP client.

My understanding for allowing this is simplicity in the sender (to treat all 100 and 1xx in a similar manner at the sender), rather than expectation that the receiver will receive it. I think this point needs to be made clearer.

Regards

Keith