Re: [core] Fwd: New Version Notification for draft-bierman-core-yid-00.txt

[Andy Bierman <[e-mail]>]

On Mon, Aug 22, 2016 at 2:01 PM, Michel Veillette <
[e-mail]> wrote:

> Hi Andy
>
>
>
> I see two fundamental differences between the SID and the YID drafts.
>
>
>
> 1) The name
>
> YID is harder to pronounce, but seem to be technically better.
>
> These IDs are not really structured, they are in fact arbitrary if we
> allocate them by range(s).
>
> But we shall use them only for YANG items if we want to keep them compact.
>
>
>



2) Allocation per range or per prefix
>
> Last winter, we moved from an allocation per prefix (20 bits, 10 bits) to
> an allocation per range(s).
>
>
>


I realize that if I ask for a range of 64K, then why should the registry
care
if I use it for manual numbering or hashing. I think module-ids
are easier to manage though.  YID proposes that a module-id be added
to the YANG Module Registry and IANA will assign the module-id.
This is how it works for the SNMP OID root for a MIB module,
which is essentially the same thing.

IMO modules should fit into 1 range, if ranges are used.




> We did this change for the following reasons:
>
> - Starvation of IDs.
>
> The size of the range can be adjusted based on the estimated number of
> items for each particular YANG module.
>
> And extra range(s) can be added if needed.
>


I think the YID registry can be scaled down as needed.
e.g., the server "knows" no module it supports has more than 256 objects so
the "local-bits" can be scaled down from 16 bits to 8 bits.




>
>
> - Efficiency
>
> An allocation based on a fixed number of bits become very inefficient,
> especially if want or minimize the ricks of starvation and to support
> multiple tiers of registration (IANA, SDO/registrars, Developers, YANG
> modules).
>
>
>
> These reasons are still valid and I hope you appreciate the advantages of
> using ranges.
>
>
>
> ==================
>
>
>
> I also want to clarify a couple of items discussed on the malling list.
>
>
>
> 1) [I-D.somaraju-core-sid] don't mandate any specific algorithm to perform
> the allocation of IDs to YANG items.
>
> Using a hash to perform this allocation is perfectly valid and the text
> should be modified to mention the possible use of a hash or any other
> algorithms.
>
>
>
> 2) manual / sequential numbering
>
> [I-D.bierman-core-yid] associate the term "manual" to sequential numbering.
>
> Since  [I-D.somaraju-core-sid] recommend the use an automated process to
> perform SIDs allocation, we should avoid the use of "manual" to qualify
> sequential numbering.
>


No -- I mean manual.
What if I want to leave some gaps in the numbering for future growth?
Since the number of CBOR bytes is 1 whether the delta is 1 or 23,
I can leave padding in the number space without any penalty in the protocol.
Sequential numbering gets very non-sequential (the more so with every new
module revision).





>
>
> ==================
>
>
>
> As a last comment, [I-D.bierman-core-yid] contain a lot of very good
> description text which should be preserved during the merging process.
>
>
>
> Regards,
>
> Michel Veillette
>
>
>


Andy



> *From:* core [mailto:[e-mail]] *On Behalf Of *Andy Bierman
> *Sent:* Tuesday, August 16, 2016 2:39 PM
> *To:* Core <[e-mail]>
> *Subject:* [core] Fwd: New Version Notification for
> draft-bierman-core-yid-00.txt
>
>
>
> FYI,
>
>
>
>
>
> Peter and I have written a new draft called "Numeric YANG Identifiers"
>
> which replaces the "YANG Hash" draft.
>
>
>
> This draft combines hash-based and manual numbering and defines
>
> a simple registry-based process for management of module and object
> identifiers.
>
>
>
> The need for a rehash procedure and rehash errors has been removed.
>
> YANG Hash is now scoped by the module identifier so there are no
> inter-module
>
> interactions.  Hash collisions within a module are not allowed.
>
> Manual assignments for colliding nodes are used to avoid the rare
> occurrence
>
> of a hash collision within the same module.
>
>
>
>
>
>
>
> Andy
>
>
>
>
>
> ---------- Forwarded message ----------
> From: <[e-mail]>
> Date: Tue, Aug 16, 2016 at 11:29 AM
> Subject: New Version Notification for draft-bierman-core-yid-00.txt
> To: Peter van der Stok <[e-mail]>, Andy Bierman <
> [e-mail]>
>
>
>
> A new version of I-D, draft-bierman-core-yid-00.txt
> has been successfully submitted by Andy Bierman and posted to the
> IETF repository.
>
> Name:           draft-bierman-core-yid
> Revision:       00
> Title:          Numeric YANG Identifiers
> Document date:  2016-08-16
> Group:          Individual Submission
> Pages:          33
> URL:            https://www.ietf.org/internet-
> drafts/draft-bierman-core-yid-00.txt
> Status:         https://datatracker.ietf.org/doc/draft-bierman-core-yid/
> Htmlized:       https://tools.ietf.org/html/draft-bierman-core-yid-00
>
>
> Abstract:
>    This document describes an encoding of YANG object identifiers using
>    numeric values instead of string values.  It combines several
>    techniques to provide optimized serialization in protocol messages.
>
> Note
>
>    Discussion and suggestions for improvement are requested, and should
>    be sent to [e-mail].
>
>
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> The IETF Secretariat
>
>
>