Re: [babel] Robert Wilton's Discuss on draft-ietf-babel-source-specific-07: (with DISCUSS and COMMENT)

["Rob Wilton (rwilton)" <[e-mail]>]

Hi Juliusz,

Thanks for addressing my comments and the explanation.

I have cleared my discuss.

Regards,
Rob


> -----Original Message-----
> From: Juliusz Chroboczek <[e-mail]>
> Sent: 21 April 2021 18:08
> To: Rob Wilton (rwilton) <[e-mail]>
> Cc: The IESG <[e-mail]>; [e-mail];
> [e-mail]; [e-mail]; Donald Eastlake <[e-mail]>
> Subject: Re: Robert Wilton's Discuss on draft-ietf-babel-source-specific-
> 07: (with DISCUSS and COMMENT)
> 
> Thanks for your comments.
> 
> > My specific discuss issue relates to clarifying the indexes of the
> 'source' and
> > 'route' tables to indicate whether they are replacing the 'prefix-len'
> elements
> > of the existing 3 tuple indexes, or adding additional elements to the
> existing
> > index, effectively making them 5 tuple indexes.
> 
> This has been fixed.
> 
> > I might be completely confused, but my understanding is that what is
> called the
> > "destination prefix" in this document, is effectively what is referred
> to as
> > the "source" in draft-ietf-babel-rfc6126bis (e.g., in the Route Table in
> > section 3.2.5), that also happens to be a prefix.  Is that right?
> 
> Not quite.  The "source" is a data structure that, in the original
> protocol, contains an originating router-id and a destination prefix plus
> some data used by the loop-avoidance algorithm.  Two routes originated by
> distinct routers have distinct sources (hence the name); OTOH, if the same
> route (same originating router and same prefix) is learnt from two
> neighbours, the two routing table entries share a single source.
> 
> This is described in RFC 8966 Section 3.2.5.
> 
> In this document, the "source" data structure is extended with a "source
> prefix/plen".  Confusion ensues, but it's too late to change the original
> protocol's terminology.
> 
> > A further confusion is that this draft seems to sometimes describes
> prefixes
> > differently from how they are described in the Babel RFC that it is
> extending.
> 
> This has been fixed, sorry for that.
> 
> >        Note that the route entry contains a source (see sections 2 and
> 3.2.5
> >        of [BABEL]) which itself contains a source prefix.  These are two
> >        very different concepts that should not be confused.
> 
> > Should this reference be to 3.2.6?
> 
> Arguably both -- the source is described in 3.2.5, while 3.2.6 describes
> the route table.
> 
> Thanks,
> 
> -- Juliusz