Subject: [nwcrg] FECFRAME version 2: new version or evolution of FECFRAME?

From: Vincent Roca <[email-masked]>
Date: Thu, 6 Oct 2016 15:54:41 +0200

Dear all,

We are looking for advice for the following question:
	Should this new FECFRAME specification be called version 2 (as it is today
	for the sake of clarity), or should it be just an evolution of FECFRAME without
	introducing any notion of version number since there is none in RFC 6363?

We have an Editor's note in the Internet-Draft (1. introduction) that summarizes
the situation:

   o  FECFRAME does not define any header/trailer (but FEC Schemes do)
      and there is no "version" field that could be used to signal this
      is FECFRAME version 2 and not version 1.  Therefore the notion of
      "version" is purely abstract and could be removed altogether
      without affecting FECFRAME interoperability at all.  Indeed, a
      receiver that only supports FECFRAME "version 1" FEC Schemes will
      not join a session for which the SDP file indicates an unsupported
      (e.g., Convolutional) FEC Scheme, since this receiver will be able
      to process neither the FEC Source Packets nor FEC Repair Packets.
      This is exactly the same behavior when a receiver wants to join a
      FECFRAME version 1 session with an unsupported Block FEC Scheme.
      From this point of view, FECFRAME version 2 extends the
      applicability of FECFRAME to new types of FEC codes in a fully
      backward compatible way.  However, supporting these new FEC codes
      does impact the FECFRAME software: implementation is seriously
      impacted due to different working modes, the notion of sliding
      encoding/decoding window being added to that of source block.
      From this point of view, adding the notion of version to FECFRAME
      makes sense to easily identify some of the capabilities of a
      FECFRAME implementation.  The current document uses the notion of
      version for the sake of clarity only.

Does anybody have any opinion on the question? Thanks in advance.
Cheers,

  Ali and Vincent