Re: [OSPF] AD Review of draft-ietf-ospf-cap

Hi Bill,

Bill Fenner wrote:
> I'm sorry for taking so long on this review.
>
> My major comment is that I think that the bit order in
> the RI TLV is confusing.  (Partly because the IETF-standard
> packet picture is confusing!)
>
> Check this combination:
>
>        0                   1                   2                   3
>        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
>       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>       |             Informational Capabilities                        |
>       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>
>       Bit       Capabilities
>
>       1         OSPF graceful restart capable [GRACE]
> ..
>
> >From the picture, this could mean 0x40000000, while I think it intends
> 0x00000001.  This may be more confusing when (if) the 33rd bit is
> assigned.  I'd recommend a description of the bit numbering, along
> the lines of
>
> Bits in the Informational Capabilities field are numbered beginning at
> 1, starting at the low-order bit of the first 32-bit word.  If further
> 32-bit words are used, the low-order bit of the second one is numbered
> 33, the next one is 65, etc.
>
> (That's just off the top of my head and may not make complete sense).
> Alternately, you could represent the bits as hex values, e.g.
> 0x1, 0x2, 0x4, 0x8, 0x10 instead of 1,2,3,4,5.
>   
Actually we did mean to start with the most significant bit in the 32 
bit field
consistent with IETF standard numbering. However, the document has 
changed over its
lifetime and it looks like we've missed bit 0. Since this TLV is for 
informational
purposes I think it would make sense to reclaim bit 0. I'll also claify 
the numbering
and contact someone regarding update of one of the existing 
implementations.

> The other item is the IANA considerations.  Normally we don't say
> that a WG is the expert, since the WG may not live forever; we say
> that the IESG designates an expert, and the IESG designates the
> current WG chairs while the WG exists.
>   
I'll replace "subject to review by the OSPF WG" with "subject to review 
by an expert
designated by the IESG".

Thanks,
Acee

>   Bill
>
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>   

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