Subject: [Rmt] Announcing draft-ietf-rmt-bb-fec-raptorq-03

From: "Luby, Michael" <[email-masked]>
Date: Tue, 22 Jun 2010 14:37:34 -0700

RMT participants,
We have just submitted a new -03 version of “RaptorQ Forward Error Correction Scheme for Object Delivery”.   There are no basic technical changes to the actual RaptorQ code (a minor technical change is noted below).  The main change between the –02 and –03 drafts is that there was an effort to remove some of the ambiguities in the –02 draft and to make it much easier to implement (this was based on feedback from a couple of people who have implemented from the draft).  For example, we removed all the mathematical discussions of GF(256), and removed introduction of complicated mathematical operations in the middle of the draft, and isolated to Section 5.7 all symbol operations relating to GF(256), where we also describe the symbol operations solely as table lookup operations instead of trying to explain finite fields. (We do mention GF(256) in Section 5.7, but it is not necessary to understand the theory of GF(256) finite field operations to implement the draft.)  We also did some other cleanups as well, e.g., eliminated a few places where we described the same thing more than once, and maintained and cleaned up the better of multiple descriptions that provided the most straightforward way to implement.  We also isolated the requirements for a compliant decoder to a new Subsection 5.8.  We feel that these changes will help future implementers, and will also make the WGLC faster and more efficient.

The minor technical change was that we did change J(K’) values for a couple of K’ values in Table 2.  We anticipate computing and validating new J(K’) values for a few other K’ values, and these will be updated along with any WGLC comments after WGLC has been completed  (these updates have no impact on the WGLC review of the draft, as from that perspective they are just values in a table, and will be available before the WGLC is completed).   We feel that this draft is now ready for WGLC.
Regards, Mike Luby