[Rmt] Re: draft-ietf-rmt-bb-fec-rs-04 LC comments
Vincent Roca <vincent.roca@inrialpes.fr> Fri, 19 October 2007 10:28 UTC
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Date: Fri, 19 Oct 2007 13:27:55 +0200
From: Vincent Roca <vincent.roca@inrialpes.fr>
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Cc: Alfred Hoenes <ah@tr-sys.de>
Subject: [Rmt] Re: draft-ietf-rmt-bb-fec-rs-04 LC comments
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Hello, We just received these comments concerning our Reed-Solomon I-D from Alfred. Cheers, Vincent Alfred Hoenes wrote: > Hello, > after studying the Internet-Draft in IETF LC authored by you, > draft-ietf-rmt-bb-fec-rs-04, > I'd like to submit a few comments, pointing out a few textual > flaws I found in that memo that should be addressed before > publicaton as an RFC. > > The items below are presented in textual order. > To give more context, sometimes I quote larger blocks of text > literally and show the replacement proposed using the shorthand > notation: > > <original draft text> > --- > <modified text> > > I use change bars ('|' in column 1) and occasionally > up/down pointing marker lines ('^^^'/'vvv') to emphasize > the location of textual issues and/or proposed corrections. > Modified text has been re-adjusted to match RFC formatting > rules, where appropriate. > > > (1) Section 1 -- word omission > > In the 4th paragraph, put in the missing verb, "is" : > > The goal of the present document to specify ... > --- > The goal of the present document is to specify ... > ^^^ > > (2) Section 4.2.4.2 -- clarification of potentially misleading text > > The last paragraph of Section 4.2.4.2 says: > > | After Base64 encoding, the 2 bytes of the FEC OTI Scheme Specific > Information are transformed into a string of 4 printable characters > | (in the 64-character alphabet) and added to the FEC-OTI-Scheme- > Specific-Info attribute. > > a) In the first line, "After" is misleading; "During" would be > appropriate; I propose to use "Via" for brevity. > b) In the third line, "and added" does not give the sentence the > proper sense; I porpose to use "that is added" instead. > > Taking altogether, the paragraph should say: > > | Via Base64 encoding, the 2 bytes of the FEC OTI Scheme Specific > Information are transformed into a string of 4 printable characters > | (in the 64-character alphabet) that is added to the FEC-OTI-Scheme- > Specific-Info attribute. > > > (3) Section 5.1 -- typo/grammar > > The last sentence above Figure 5 does not parse; please change > > This FEC Payload ID refer to ... > --- ^ > This FEC Payload ID refers to ... > ^^ > > (4) Section 8.1 -- text simplification > > Near the end of the first paragraph of Section 8.1, the draft says: > > ... the > multiplication is the multiplication modulo a given irreducible > | polynomial over GF(2) of degree m with coefficients in GF(2). [...] > ^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^ > > Actually, "over GF(2)" and "with coefficients in GF(2)" mean exactly > the same. This equivalence is already explaned a few lines above, > in the same paragraph. > Hence, this redundancy should be removed, one of the two marked parts > should be deleted; I leave it to your choice, which to choose! > > > (5) Section 8.1 -- clarification > > The second paragraph of Section 8.1 says: > > | A finite field GF(2^^m) is completely characterized by the > irreducible polynomial. [...] > > The preceding paragraph already has stated more precisely that this > is a polynomial *representation* of the structurally unique field. > The polynomial characterizes this representation. > For the sake of mathematical precision, I therefore recommend to > improve the wording of that sentence to say: > > | The choosen polynomial representation of the finite field GF(2^^m) > is completely characterized by the irreducible polynomial. [...] > > > (6) Section 8.4 -- textual improvement > > The second paragraph of Section 8.4 says: > > [...] If some of the source symbols contain less than S elements, > | they MUST be virtually padded with zero elements (it can be the > case for the last symbol of the last block of the object). > [...] > > It should better say: > > [...] If some of the source symbols contain less than S elements, > | they MUST be virtually padded with zero elements (this can be the > case for the last symbol of the last block of the object). > [...] ^^^^ > > > (7) Section 8.4 -- confusing overloading of the named index 'j' > > Up to and including Figure 7, the index j (from {0..S01}) is used > to select a particular m-bit element from each source symbol or > encoding symbol, i.e. it is a column index in the upper and the > bottom part of Figure 7. > > Confusingly, 'j' is overloaded in the last paragraph of the Section > with a very different meaning, as a row index in the bottom part > of Figure 7. This should be avoided; in that context, 'j' should > be replaced by another variable name not yet used, e.g. 'i'. > > Hence, the final paragraph of Section 8.4 should be changed to say: > > Another asset is that the n-k repair symbols can be produced on > demand. For instance, a sender can start by producing a limited > number of repair symbols and later on, depending on the observed > erasures on the channel, decide to produce additional repair symbols, > | up to the n-k upper limit. Indeed, to produce the repair symbol e_i, > v ^ > | where k <= i < n, it is sufficient to multiply the S source vectors > | with column i of GM. > ^ > > (8) Section 12.2 -- outdated reference > > Apparently, ref. [9] has been published as RFC 5053 in September, > long before the current draft revision has been posted. > > > Best regards, > Alfred Hoenes. > > +------------------------+--------------------------------------------+ > | TR-Sys Alfred Hoenes | Alfred Hoenes Dipl.-Math., Dipl.-Phys. | > | Gerlinger Strasse 12 | Phone: (+49)7156/9635-0, Fax: -18 | > | D-71254 Ditzingen | E-Mail: ah@TR-Sys.de | > +------------------------+--------------------------------------------+ _______________________________________________ Rmt mailing list Rmt@ietf.org https://www1.ietf.org/mailman/listinfo/rmt
- [Rmt] Re: draft-ietf-rmt-bb-fec-rs-04 LC comments Vincent Roca