Re: [Isis-wg] WG Adoption Call for draft-xu-isis-encapsulation-cap

[Xuxiaohu <[e-mail]>]

Hi Les,

I wonder whether the End Point sub-TLV as described in Section 5.3 can address your concerns.

Best regards,
Xiaohu

> -----Original Message-----
> From: Xuxiaohu
> Sent: Monday, February 29, 2016 5:07 PM
> To: 'Hannes Gredler'; Les Ginsberg (ginsberg)
> Cc: [e-mail] list; Christian Hopps
> Subject: RE: [Isis-wg] WG Adoption Call for draft-xu-isis-encapsulation-cap
> 
> Hi Hannes and Les,
> 
> The End Point sub-TLV as described in Section 5.3 is just used to indicate the
> tunnel endpoint address(es).
> 
> Best regards,
> Xiaohu
> 
> > -----Original Message-----
> > From: Isis-wg [mailto:[e-mail]] On Behalf Of Hannes
> > Gredler
> > Sent: Monday, February 29, 2016 4:21 PM
> > To: Les Ginsberg (ginsberg)
> > Cc: [e-mail] list; Christian Hopps
> > Subject: Re: [Isis-wg] WG Adoption Call for
> > draft-xu-isis-encapsulation-cap
> >
> > hi les,
> >
> > On 2/27/16 19:28, Les Ginsberg (ginsberg) wrote:
> > > Hannes -
> > >
> > > Discovery of tunnel endpoints is not what this draft is about.
> > >
> > > I am saying that I do not see that announcing tunnel capabilities is useful.
> > Discovering tunnel endpoints obviously is useful - as is identifying
> > endpoint addresses - but this draft will help us do neither.
> >
> > agreed - IP prefix info is missing ...
> > i can see two ways to fix this:
> >
> > 1. explicitly state that the tunnel-encaps-cap refers to a particular
> >     IP prefix
> > 2. move the tunnel-encaps-cap underneath an IP prefix TLV
> >
> > we should be good the, right ?
> >
> > /hannes
> >
> > >
> > >> -----Original Message-----
> > >> From: Hannes Gredler [mailto:[e-mail]]
> > >> Sent: Saturday, February 27, 2016 9:52 AM
> > >> To: Les Ginsberg (ginsberg)
> > >> Cc: Uma Chunduri; Christian Hopps; [e-mail] list
> > >> Subject: Re: [Isis-wg] WG Adoption Call for
> > >> draft-xu-isis-encapsulation-cap
> > >>
> > >> hi les,
> > >>
> > >> <wg-chair hat off>
> > >>
> > >> On Sat, Feb 27, 2016 at 05:18:39PM +0000, Les Ginsberg (ginsberg) wrote:
> > >> |    From my POV the draft currently defines how to advertise new
> > >> |    information without defining why it is necessary to do so.
> > >>
> > >> agree - "discovery of tunnel endpoints" should be explicitly spelled out.
> > >>
> > >> |
> > >> |    Yes, multiple tunnel types may be in use in the network - that does
> not
> > >> |    in and of itself lead to a requirement to advertise supported tunnel
> > >> |    types . In most cases, the support of a given tunnel type can be
> known
> > >> |    today by other means. You give the example of RLFA - but today LDP
> > >> |    reachability to an endpoint is something a router already knows - and
> > >> |    this is the real requirement to setup an RLFA tunnel. Knowing that the
> > >> |    endpoint is capable of supporting RLFA is insufficient. Further, folks
> > >> |    (including you if I recall correctly) have indicated that they want
> > >> |    more than just knowing RLFA capability - they also want to know
> what
> > >> |    endpoint address to use. This logically leads to the use of admin tags
> > >> |    which will not only indicate support for the tunnel type but also what
> > >> |    endpoint address is preferred/required.
> > >>
> > >> guess the RLFA example refers to non-MPLS (IP-only deployments)
> > >>
> > >> |    I think more thought and discussion is required before deciding that
> > >> |    this is something that should be supported. And I think this needs to
> > >> |    be done BEFORE this becomes a WG document as - almost without
> > >> exception
> > >> |    - anything that becomes a WG document proceeds to become an
> RFC.
> > >>
> > >> IMO the generic ability to discover tunnel-endpoints is something
> desireable.
> > >> agreed that the actual use-cases should be (better) documented
> > >> somewhere (perhaps in RTGWG ?), but we can do that after WG
> > >> adoption as well.
> > >>
> > >> - or is it that you want to make a case that discovery of tunnel
> > >> endpoints is not desired at all ?
> > >>
> > >> /hannes
> > >>
> > >> |    From: Uma Chunduri [mailto:[e-mail]]
> > >> |    Sent: Friday, February 26, 2016 12:09 PM
> > >> |    To: Uma Chunduri; Les Ginsberg (ginsberg); Christian Hopps;
> > >> |    [e-mail] list
> > >> |    Subject: RE: [Isis-wg] WG Adoption Call for
> > >> |    draft-xu-isis-encapsulation-cap
> > >> |
> > >> |
> > >> |    Dear Les et. al,
> > >> |
> > >> |
> > >> |    Please post any further comments you might have on this document.
> > >> |
> > >> |
> > >> |    --
> > >> |
> > >> |    Uma C.
> > >> |
> > >> |
> > >> |    From: Isis-wg [[1]mailto:[e-mail]] On Behalf Of Uma
> > >> |    Chunduri
> > >> |    Sent: Thursday, January 14, 2016 4:51 PM
> > >> |    To: Les Ginsberg (ginsberg); Christian Hopps; [2][e-mail] list
> > >> |    Subject: Re: [Isis-wg] WG Adoption Call for
> > >> |    draft-xu-isis-encapsulation-cap
> > >> |
> > >> |
> > >> |    Les,
> > >> |
> > >> |
> > >> |    Thanks for your comments, see in line [Uma]:
> > >> |
> > >> |    --
> > >> |
> > >> |    Uma C.
> > >> |
> > >> |
> > >> |    From: Isis-wg [[3]mailto:[e-mail]] On Behalf Of Les
> > >> |    Ginsberg (ginsberg)
> > >> |    Sent: Tuesday, January 12, 2016 5:25 PM
> > >> |    To: Christian Hopps; [4][e-mail] list
> > >> |    Subject: Re: [Isis-wg] WG Adoption Call for
> > >> |    draft-xu-isis-encapsulation-cap
> > >> |
> > >> |
> > >> |    Apologies for the very late response on this...
> > >> |
> > >> |
> > >> |    I have a couple of concerns regarding taking on this work.
> > >> |
> > >> |
> > >> |    The draft is straightforward enough in terms of the protocol
> extensions
> > >> |    defined, but I am not at all clear on the usefulness of the information
> > >> |    being advertised. The introduction to the draft discusses a variety of
> > >> |    tunnel types which might be used in a network but does not offer an
> y
> > >> |    reason why advertising the tunnel types supported is of benefit.
> > >> |
> > >> |
> > >> |    [Uma]: Lot of use cases have been described where there is no
> > >> |    configuration possible for all possible egress nodes at a given ingress
> > >> |    node; as asymmetric connections can be made dynamically based
> > >> | on
> > the
> > >> |    network topology; using the tunnel capabilities or parameters of
> egress
> > >> |    node  from ingress.
> > >> |
> > >> |
> > >> |    Given this information is only advertised within a single
> > >> |    administrative domain it does not seem to provide any information
> that
> > >> |    is not already known to the network operator.
> > >> |
> > >> |    [Uma]: This is not about whether network operators know all the
> > >> |    information but it's about if it is possible to
> > >> | configure/manage
> > >> |
> > >> |    a.       all options supported by possible egress nodes from ingress
> > >> |    nodes perspective or
> > >> |
> > >> |    b.      one option of all "possible" egress nodes from ingress nodes
> > >> |    pov.
> > >> |
> > >> |
> > >> |    It also logically leads to requiring a configuration for what tunnel
> > >> |    types to advertise. If this information is meant to drive automatic
> > >> |    configuration of tunnels I presume that the network operator
> > >> | would
> > want
> > >> |    to limit what is advertised - not simply accept what the
> implementation
> > >> |    is capable of supporting. So it seems we have simply traded one
> > >> |    configuration for another.
> > >> |
> > >> |    [Uma]: I don't see, we have traded any configuration here. An in-line
> > >> |    ingress application/feature  running as part of IS-IS ought to know
> > >> |    what kind of tunnel capabilities the egress node is capable of
> > >> |    accepting and associated parameters thereof for that tunnel.
> > Network
> > >> |    operator can always limit enabling  capabilities that are being
> > >> |    supported and capabilities that are being advertised by an egress
> node
> > >> |    as part of ISIS through configuration.
> > >> |
> > >> |
> > >> |    I would like to see more detail on this before deciding whether it is
> > >> |    worth doing.
> > >> |
> > >> |
> > >> |    It is clear that the information is not at all useful to IS-IS itself -
> > >> |    which brings me to my second concern. This is advertising
> information
> > >> |    that has nothing to with IS-IS. Router Capabilities is not meant to be
> > >> |    used as a vehicle to advertise information not of direct use to the
> > >> |    protocol.
> > >> |
> > >> |    [Uma]:  I am not sure why you see it is not all useful to IS-IS ; most
> > >> |    of the features/applications listed in  section 1 are related to  ISIS
> > >> |    protocols. For example RLFA- computation of PQ nodes done
> > >> | after
> > >> primary
> > >> |    SPF and as part of RLFA  SPFs (neighbor SPF, neighbors rSPF) and PQ
> > >> |    nodes are computed dynamically on the current topology. It's not
> > >> |    conceivable to provision an ingress node with one/all tunnel
> > >> |    capabilities of egress nodes (essentially where ever this feature is
> > >> |    enabled and potentially all eventually).  Similarly for Spring/Bier
> > >> |    nodes dynamic tunnels can be supported based on the neighboring
> > >> |    non-spring/non-bier node capabilities advertised.
> > >> |
> > >> |
> > >> |    In fact, the existence of a couple of exceptions to this guideline is
> > >> |    what prompted the creation of GENAPP (RFC 6823) as the
> appropriate
> > >> |    place to advertise such information.
> > >> |
> > >> |
> > >> |    I would like to see further discussion of the above before deciding
> > >> |    that WG adoption (which almost always indicates an intent to
> progress
> > >> |    to RFC) is appropriate.
> > >> |
> > >> |
> > >> |        Les
> > >> |
> > >> |
> > >> |
> > >> |    From: Isis-wg [[5]mailto:[e-mail]] On Behalf Of
> > >> |    Christian Hopps
> > >> |    Sent: Monday, November 30, 2015 11:45 PM
> > >> |    To: [6][e-mail] list
> > >> |    Subject: Re: [Isis-wg] WG Adoption Call for
> > >> |    draft-xu-isis-encapsulation-cap
> > >> |
> > >> |
> > >> |    [It seems due to some sneaky cut and paste error, the URL was
> > >> | wrong
> > in
> > >> |    the original email, I've corrected in this message]
> > >> |
> > >> |
> > >> |    Hi Folks,
> > >> |    The authors have requested the IS-IS WG adopt:
> > >> |
> > >> |
> > >> |
> > >> | [7]https://datatracker.ietf.org/doc/draft-xu-isis-encapsulation-c
> > >> | ap
> > >> | /
> > >> |
> > >> |
> > >> |    as a working group document.
> > >> |
> > >> |    Please indicate support or no-support for taking on this work.
> > >> |    Thanks,
> > >> |    Chris.
> > >> |
> > >> | References
> > >> |
> > >> |    1. mailto:[e-mail]
> > >> |    2. mailto:[e-mail]
> > >> |    3. mailto:[e-mail]
> > >> |    4. mailto:[e-mail]
> > >> |    5. mailto:[e-mail]
> > >> |    6. mailto:[e-mail]
> > >> |    7.
> > >> | https://datatracker.ietf.org/doc/draft-xu-isis-encapsulation-cap/
> > >>
> > >> | _______________________________________________
> > >> | Isis-wg mailing list
> > >> | [e-mail]
> > >> | https://www.ietf.org/mailman/listinfo/isis-wg
> > >
> >
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