Re: [Pce] PCEP Codepoints

[JP Vasseur <jvasseur at cisco.com>]

Hi Adrian,


> From: Adrian Farrel <adrian at olddog.co.uk>
> Reply-To: Adrian Farrel <adrian at olddog.co.uk>
> Date: Thu, 20 Mar 2008 16:21:18 -0000
> To: <pce at ietf.org>
> Subject: [Pce] PCEP Codepoints
> 
> Hi,
> 
> ATTENTION!
> Authors of PCEP, XRO, BRPC and Path-Key.
> 
> I updated the temporary registry at http://www.olddog.co.uk/pce.htm
> 
> This is based on pcep-11 xro-04, brpc-05, and path-key-02
> 
> What I found was...
> 
> PCEP is a bit of a mess, sometimes numbering bits from most-significant and
> sometimes numbering from least-significant. Sometimes the count starts at
> zero, sometimes at one. I believe I have reproduced what the PCEP draft
> says, but do we want to fix it? It's probable that IANA will get confused
> unless we get some consistency.

Let me look at it, not sure that we need any change though.

> 
> Maybe best to count all bits left-to-right (most to least significant)
> starting at zero. This seems to be the usual IETF way.
> 
> Maybe good to also show the hex for each bit.
> 
> That would be a revision of PCEP, but it would fit in the review cycle if it
> was done quickly.
> 
> 
> I believe I also found two points of confusion in BRPC...
> 
> 14.1 defines the VSPT (V-bit) as
> "Bit Number: 10
>  Value: 0x60"
> I may be old, but I am not aware of a way to encode 0x60 as a single bit.
> Note also, however, that the registry for "Request Parameters Bit Flags" has
> a couple of unassigned bits. Maybe you'd like to close the gap?
> 
> 14.2 assigns a new bit as
> "Bit number (suggested value): 0x04"
> If this is supposed to be the bit number (i.e. it number 4) this fits with
> the PCEP registry. But if it is supposed to be the hex representation of the
> bit-field note that PCEP says that the count starts at zero and assigns bits
> 1, 2, and 3. So 0x04 is already assigned.
> 

We fixed those issues in version -07 (February 8, 2008).

15.1.  New flag of the RP object

   A new flag of the RP object (specified in [I-D.ietf-pce-pcep]) is
   defined in this document.

   VSPT Flag
   Bit Number      Name Flag    Reference
     7                VSPT      This document


15.3.  New flag of the NO-PATH-VECTOR TLV

   A new flag of the NO-PATH-VECTOR TLV defined in [I-D.ietf-pce-pcep])
   is specified in this document.

    Bit number  Meaning                  Reference

       4        BRPC Path computation   This document
                chain unavailable

> 
> In Path-Key section 7.3, I found the RP object bits numbered from the other
> end.
> In section 7.4, there is an allocaiton from the No-Path Vector TLV bit
> flags, and an attempt is made to allocate bit 1. This is already in use for
> PCEP.

Richard, could you fix it in the next revision (thanks) ?

Cheers,

JP.

> 
> 
> Please fix drafts and let me know the updates.
> 
> Thanks,
> Adrian 
> 
> 
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