Re: [Idr] I-D Action: draft-previdi-idr-segment-routing-te-policy-07.txt

Thank you Stefano for clarifying.

On Mon, Jul 17, 2017 at 6:12 PM, stefano previdi <stefano@previdi.net>
wrote:

> Hi Nandan,
>
> sorry for being late. See below.
>
>
> > On Jul 3, 2017, at 2:14 PM, Nandan Saha <nandan@arista.com> wrote:
> >
> > Hello!
> >
> > I have some questions on the NLRI encoding.
> > 1. Can the value of NLRI length be less than 96 for IPv4 AFI and less
> > than 192 for IPv6 AFI? IOW, can it be less than full mask length for
> > the end point address?
>
> no.
>
>
> > 2. If the answer to (1) is "yes", then what is the rationale for
> > keeping the end point address field of the NLRI fixed length? (4 or 16
> > bytes depending on AFI). Should the end point become variable length
> > like the NLRI encoding defined in RFC4760?
> > 3. If the answer to (1) is "no", how are summary addresses to be
> represented?
>
>
> there’s no such concept of “summary address” for the endpoint encoding.
> The draft is going to be updated and the term “summary address” will be
> removed from the endpoint filed description. Sorry for the confusiuon.
>
>
> > Another question which is unrelated to the changes in version 7 of the
> draft.
> > Section "4.2.1. Acceptance of an SR Policy NLRI" says
> > " If the NLRI is not one of the legal lengths, a router supporting
> > this document and that imports the route MUST consider it to be
> > malformed and MUST apply the "treat-as-withdraw" strategy of [RFC7606]
> > "
> > It's not clear to me how a receiver can extract a valid route from a
> > malformed NLRI.
>
>
> you just have to check the nlri length.
>
>
> > The "treat-as-withdraw" can be applied if the NLRI is
> > well formed but some other attributes are malformed, which seems to be
> > implied by the following line at the end of the subsection
> > "A unacceptable SR Policy update that has an invalid NLRI portion MUST
> > trigger a reset of the BGP session.”
>
>
> that is correct.
>
> s.
>
>
> >
> > Thank you!
> > Best regards,
> > Nandan
> >
> > On Sat, Jun 24, 2017 at 1:30 AM, <internet-drafts@ietf.org> wrote:
> >>
> >>
> >> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
> >> This draft is a work item of the Inter-Domain Routing of the IETF.
> >>
> >>        Title           : Advertising Segment Routing Policies in BGP
> >>        Authors         : Stefano Previdi
> >>                          Clarence Filsfils
> >>                          Paul Mattes
> >>                          Eric Rosen
> >>                          Steven Lin
> >>        Filename        : draft-previdi-idr-segment-
> routing-te-policy-07.txt
> >>        Pages           : 30
> >>        Date            : 2017-06-23
> >>
> >> Abstract:
> >>   This document defines a new BGP SAFI with a new NLRI in order to
> >>   advertise a candidate path of a Segment Routing Policy (SR Policy).
> >>   An SR Policy is a set of candidate paths consisting of one or more
> >>   segment lists.  The headend of an SR Policy may learn multiple
> >>   candidate paths for an SR Policy.  Candidate paths may be learned via
> >>   a number of different mechanisms, e.g., CLI, NetConf, PCEP, or BGP.
> >>   This document specifies the way in which BGP may be used to
> >>   distribute candidate paths.  New sub-TLVs for the Tunnel
> >>   Encapsulation Attribute are defined.
> >>
> >>
> >> The IETF datatracker status page for this draft is:
> >> https://datatracker.ietf.org/doc/draft-previdi-idr-segment-
> routing-te-policy/
> >>
> >> There are also htmlized versions available at:
> >> https://tools.ietf.org/html/draft-previdi-idr-segment-
> routing-te-policy-07
> >> https://datatracker.ietf.org/doc/html/draft-previdi-idr-
> segment-routing-te-policy-07
> >>
> >> A diff from the previous version is available at:
> >> https://www.ietf.org/rfcdiff?url2=draft-previdi-idr-
> segment-routing-te-policy-07
> >>
> >>
> >> 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.
> >>
> >> Internet-Drafts are also available by anonymous FTP at:
> >> ftp://ftp.ietf.org/internet-drafts/
> >>
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> >
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