[Ndn-interest] Proposed deprecation: byte offset segmenting

Junxiao Shi shijunxiao at email.arizona.edu
Wed Jan 30 17:56:36 PST 2019


Dear folks

20190130 NFD call discussed this issue.
While there aren’t many use cases, the cost of preserving byte offset
segmenting is low.
Therefore, Alex abandoned his plan of deprecating byte offset segmenting.

A use case I can think of is segmenting content at non uniform chunk sizes,
e.g. boundary determined by Rabin fingerprints. I had a related project
although it does not directly use byte offset segmenting:
Content-Addressable NDN Repository https://github.com/yoursunny/carepo
Retrieval of byte offset segmented content would require either
stop-and-wait, or a manifest listing all segment boundaries to enable
pipelining.

Yours, Junxiao

On Tue, Jan 29, 2019 at 15:28 Nick Briggs <nicholas.h.briggs at gmail.com>
wrote:

> What is the benefit of removing it from the specification (or the cost of
> leaving it) ?
>
> -- Nick
>
>
> > On Jan 29, 2019, at 12:22 PM, Junxiao Shi <shijunxiao at email.arizona.edu>
> wrote:
> >
> > Dear folks
> >
> > NDN Naming Conventions revision 1 defines two segmenting markers: 0x00
> and 0xFB.
> > 0x00 is the segment number marker. Segments of a content are assigned
> consecutive segment numbers.
> > It is commonly used in many applications, including ndnputchunks, NDNFS,
> and PSync.
> >
> > 0xFB is the byte offset marker. Segments of a content are given this
> marker followed by payload's byte offset within the content.
> > We are unaware of any application that adopts the 0xFB byte offset
> marker.
> > Moreover, unless using a manifest, the consumer cannot predict the byte
> offset of every segment, and thus hinders the efficiency of content
> retrieval because pipelining cannot be used.
> >
> > Alex has promised to discontinue byte offset segmenting in NDN Naming
> Conventions revision 2.
> > If anyone on this mailing list has an application that currently uses
> 0xFB marker, please speak up within 5 days.
> >
> > Yours, Junxiao
> > _______________________________________________
> > Ndn-interest mailing list
> > Ndn-interest at lists.cs.ucla.edu
> > http://www.lists.cs.ucla.edu/mailman/listinfo/ndn-interest
>
>
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