Last Call Review of draft-ietf-tsvwg-sctp-prpolicies-05
review-ietf-tsvwg-sctp-prpolicies-05-opsdir-lc-romascanu-2014-12-01-00

I have reviewed this document as part of the Operational directorate's ongoing
effort to review all IETF documents being processed by the IESG.  These
comments  were written primarily for the benefit
 of the operational area directors.  Document editors and WG chairs should
 treat these comments just like any other last call comments.



Summary: Ready with issues



Document Ready, but Operational and Management considerations missing.



As the Abstract says:



   This document defines two additional policies for the Partial

   Reliability Extension of the Stream Control Transmission Protocol

   (PR-SCTP) allowing to limit the number of retransmissions or to

   prioritize user messages for more efficient send buffer usage.

Although this document defines an extension of an existing protocol, there are
no explicit considerations about operations and management. The OPS and
Transport ADs should decide whether this
 is an issue to be addressed before the document is approved.



Specifically, following the checklists in RFC 5707, Appendix A:



-



Deployment is not discussed, although there is text that says that the Limited
Retransmissions Policy can be used with data channels in the
 WebRTC protocol stack, and that the Priority Policy can be used in the IPFIX
 protocol stack

-



Installation and initial setup is not discussed

-



Migration Path does not seem to apply

-



There is information about RFC 3758 being mandatory to implement in order to
implement these extensions

-



The impact on the network operation is not discussed explicitly

-



There are no explicit suggestions about verifying correct operations, although
one can understand that the socket options described in sections
 4.3, 4.4, 4.5 are useful to determine stream specific status, association
 specific status, and to get and set the PR-SCTP support

-



Interoperability does not seem to apply excepting the requirement to implement
RFC 3758

-



There is no information about faults or threshold conditions to be reported

-



Configuration is not discussed, it may not apply, but it would be good to state
this

-



There are no manageability considerations of any kind



One terminology issue is worth being considered: The document speaks about two
additional policies for PR-SCTP. However, the RFC defining PR-SCTP (RFC 3758)
does not use
 the term policy at all. Timed Reliability which in this document is called a
 ‘policy’ is described in RFC 3758 as a ‘service to upper layer’. It would be
 good to either align terminology, or to explain that the term policy used here
 corresponds to the ‘service’ described in RFC 3758.



Regards,



Dan