Re: [sfc] New Version Notification for draft-vandevelde-sfc-nsh-length-overload-00.txt

> On Oct 17, 2016, at 12:10 PM, Dave Dolson <ddolson@sandvine.com> wrote:
> 
> 
> I would prefer to see the length field always mean length, so that implementations not requiring metadata can just skip the metadata regardless of MD type. 

I agree with this. I’d much rather keep the Length to mean just Length for all MD Types.

Thanks,

— Carlos.

> 
> At the risk of stating the obvious, there already is an MD type field that can be used to discriminate metadata allocations. Values 3,4,5,... are available for different MD encodings.
> 
> -Dave
> 
> ________________________________________
> From: sfc [sfc-bounces@ietf.org] on behalf of Ron Parker [Ron_Parker@affirmednetworks.com]
> Sent: Monday, October 17, 2016 10:50 AM
> To: Van De Velde, Gunter (Nokia - BE); sfc@ietf.org
> Subject: Re: [sfc] New Version Notification for draft-vandevelde-sfc-nsh-length-overload-00.txt
> 
> Gunter,
> 
> I strongly support this proposal.   It brings more specificity to Type 1 which will undoubtedly improve interworking between different implementations and between different administrative domains.
> 
>   Ron
> 
> 
> -----Original Message-----
> From: sfc [mailto:sfc-bounces@ietf.org] On Behalf Of Van De Velde, Gunter (Nokia - BE)
> Sent: Monday, October 17, 2016 5:15 AM
> To: sfc@ietf.org
> Subject: [GRAYMAIL] [sfc] FW: New Version Notification for draft-vandevelde-sfc-nsh-length-overload-00.txt
> 
> Short text about overloading NSH length field for NSH MD Type-1 as context allocation type, including proposal for backward compatibility.
> 
> G/
> 
> ------
> 
> On 17/10/2016, 10:05, "internet-drafts@ietf.org" <internet-drafts@ietf.org> wrote:
> 
> 
>    A new version of I-D, draft-vandevelde-sfc-nsh-length-overload-00.txt
>    has been successfully submitted by Gunter Van de Velde and posted to the
>    IETF repository.
> 
>    Name:               draft-vandevelde-sfc-nsh-length-overload
>    Revision:   00
>    Title:              Network Services Header Context Allocation Identifier
>    Document date:      2016-10-17
>    Group:              Individual Submission
>    Pages:              5
>    URL:            https://www.ietf.org/internet-drafts/draft-vandevelde-sfc-nsh-length-overload-00.txt
>    Status:         https://datatracker.ietf.org/doc/draft-vandevelde-sfc-nsh-length-overload/
>    Htmlized:       https://tools.ietf.org/html/draft-vandevelde-sfc-nsh-length-overload-00
> 
> 
>    Abstract:
>       The specification of the NSH MD Type 1 header [draft-ietf-sfc-nsh]
>       mandates four Context Headers, 4-byte each, and they MUST be added
>       immediately following the Service Path Header.  As direct
>       consequence, an NSH MD Type 1 header is always Length 0x6 (six 4-byte
>       words).  As a result, the Length field of the NSH MD Type 1 header
>       provides an information which is known by simply looking at the "MD
>       Type" field.  However, while [draft-ietf-sfc-nsh] does not specify
>       the encoding of these Context Headers, other specifications have
>       started to do so.  A need to distinguish types of Context Headers
>       therefore arises.
> 
>       This draft proposes to overload the Length field of an NSH MD Type 1
>       as Meta-Data context allocation identifier and to create a IANA
>       repository for NSH MD Type 1 allocation schemes.  The NSH MD Type 1
>       Length field overload intends to allow universal understanding at any
>       network location and by any network device of the context allocation
>       structure.
> 
> 
> 
> 
> 
>    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
> 
> 
> 
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