Re: [GROW] Genart last call review of draft-ietf-grow-bgp-gshut-11

[Job Snijders <[e-mail]>]

On Tue, Oct 10, 2017 at 09:56:45AM +0000, [e-mail] wrote:
> > Minor issues:
> > 
> > In Section 4. "EBGP graceful shutdown procedure", it states that 0
> > can used in all cases except where the AS already has a special
> > meaning for 0. It seems to me more ought to be said, but I admit I'm
> > not well-versed on (I) BGP and might be seeing dragons where only
> > windmills are present.
>  
> [Bruno] 
> I'm not seeing much more to say. It's intended as a warning that an AS
> may already use LOCAL_PREF zero to mean something specific. In which
> case, the AS knows the specifics,  authors/IETF/draft/RFC do not.
> I'm changing to the following reformulation. Please feel free to
> suggest text if you prefer.
>  
> OLD: The LOCAL_PREF value must be lower than the one of the alternate
> path. 0 being the lowest value, it can be used in all cases, except if
> it already has a special meaning within the AS.
> NEW: The LOCAL_PREF value SHOULD be lower than the one of the
> alternate path. Zero being the lowest value, it MAY be used whichever
> LOCAL_PREF values are used by the AS. If LOCAL_PREF zero already has a
> special meaning within the AS, and there is a need to distinguish both
> usages, another low value MAY be used.

Any attribute (origin, as_path, aggregator) anywhere can be overloaded
to mean something only significant to the local network. I think the
document is simpler without this and see no point in mentioning this. I
propose:

OLD:
    The LOCAL_PREF value must be lower than the one of the alternate
    path. 0 being the lowest value, it can be used in all cases, except
    if it already has a special meaning within the AS.
NEW:
    The LOCAL_PREF value SHOULD be lower than any of the alternative
    paths. It is RECOMMEND to use 0, the lowest LOCAL_PREF value.

Kind regards,

Job

ps. I-D.ietf-idr-shutdown can reference RFC 8203 now.