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

[Xuxiaohu <[e-mail]>]

Hi Marc,

> -----Original Message-----
> From: Marc Binderberger [mailto:[e-mail]]
> Sent: Monday, March 07, 2016 4:57 AM
> To: Xuxiaohu
> Cc: Les Ginsberg; Hannes Gredler; Uma Chunduri; Christian Hopps;
> [e-mail] list
> Subject: Re: [Isis-wg] WG Adoption Call for draft-xu-isis-encapsulation-cap
> 
> Hello Xiaohu,
> 
> thanks for the detailed reply and my apology for the delay in response.
> 
> 
> As I said, personally I think RFC5512 is "uber-engineered", i.e. they do more
> than the minimum they need to. I would actually disagree with the section 10
> you quoted from the new draft. For eBGP setups - peerings, VPNs with
> endpoints under customer control - I see a reason, that is when crossing
> administrative boundaries. But that's the BGP/IDR area and they solve different
> problems.
> 
> 
> For IS-IS what I propose (and Les, if I understand him right :-) is not ...
> 
> > Let me give you an example, you have 100 nodes in a single
> > administrative domain, do you want to configure on each of them the
> > encapsulation capability of the other 99 nodes?  And when you add one
> > router to the administrative domain, do you hope to configure the
> > tunnel encapsulation capability of that new router on those 100 routers?
> 
> ... a manual configuration of the tunnel endpoints. What you configure are the
> parameters of a tunnel, except the endpoint address.
> 
> What is proposed is this:
> 
> (1) you configure your IS-IS to use tunnels, if needed. This knob should exist
> anyway, to give full control to the operator, even with your proposal.
> 
> (2) you configure: "administrative tag X means a GRE tunnel for IPv4, IPv6 and
> MPLS over IPv4/v6". Preference/weight is W. Your own IP address for this is A.
> 
> You may add more tunnel technologies if needed.
> What IS-IS does with the configuration is:
> 
> (a) announce A with an administrative tag of X
> (b) if native forwarding is not possible, check if we are allowed to use tunnels
> and if the router on the other side of the zone announces an IP address A' with
> one of the configured administrative tags, e.g. X. If so, use a tunnel with the
> parameters as configured, source address A and destination address A' for
> forwarding.
> 
> 
> In reality, as the number of vendors/platforms is limited, you won't have many
> of these config lines. Likely you will have one on all machines.
> 
> 
> Even in your proposal I still would need something like (2) for
> administrative purpose:  you may restrict the tunnel technologies in use,
> because you know there is a bug or just to limit the operational burden. Or
> your GRE encaps is preferable as your ASIC does it in a single pass while
> VxLAN-gpe requires a 2nd loop; you offer/use both but you have a preference.
> 
> 
> > Manual configuration is workable. However, it would be more convenient if
> > the tunnel encapsulation capability could be automatically discovered.
> 
> See above. To summarize:
> 
> * we are _not_ talking about configuring every tunnel manually when we say
> "use an administrative tag". The ability to use a tunnel is learned via IS-IS
> updates.
> 
> * we actually get the tunnel functionality with administrative tags, without
> adding new TLVs.
> 
> * For administrative purposes your proposal will end up with similar
> configurations. In your case to restrict/prefer, in the tag case to
> define/allow/prefer.
> 
> 
> 
> The tag proposal is following the idea of going with the least amount of
> protocol changes and that the operator ensures the necessary tunnel types are
> available/configured. Your proposal (and RFC5512) follows more the idea that
> things automagically work.

Your understanding is correct that this draft follows the idea of RFC5512. That's to say, it allows automatical discovery of the tunnel decapsulation capability of tunnel egress nodes). The tunnel decapsulation capability includes but not limited to tunnel types, tunnel parameters (e.g., GRE key, L2TP session ID and cookie) and encapsulated protocols. In contrast with the tag proposal, there is no need for operators to manually configure many mappings between tags and tunnel decapsulation capabilities on each router. The manual configuration of such mappings is error-prone and therefore should be avoided if possible, IMHO.

Best regards,
Xiaohu

> Regards, Marc
> 
> 
> 
> 
> On Tue, 1 Mar 2016 01:58:01 +0000, Xuxiaohu wrote:
> > Hi Marc,
> >
> >> -----Original Message-----
> >> From: Isis-wg [mailto:[e-mail]] On Behalf Of Marc
> >> Binderberger
> >> Sent: Monday, February 29, 2016 6:42 PM
> >> To: Les Ginsberg; Hannes Gredler; Uma Chunduri
> >> Cc: Christian Hopps; [e-mail] list
> >> Subject: Re: [Isis-wg] WG Adoption Call for draft-xu-isis-encapsulation-cap
> >>
> >> Hello everyone,
> >>
> >> Uma, thanks for the replies and clarifications. After reading them and
> >> looking
> >> again at RFC5512 I understand better. But I also understand Les better ;-)
> >>
> >>
> >> IMHO even RFC5512 is uber-engineered but for BGP I can at least think of
> >> one
> >> case where you need a dynamic learning of tunnel parameters (route
> servers,
> >> where you have peerings without explicitly configuring them).
> >
> > IMHO, RFC5512 is more applicable in the case where tunnels are used within
> > a single administrative domain rather than across multiple administrative
> > domains. Of course, a single administrative domain could consist of
> > multiple ASes.
> >
> > BTW, RFC5512 is to be replaced by
> > https://tools.ietf.org/html/draft-ietf-idr-tunnel-encaps-01. It said
> > clearly in the latter draft that
> >
> > "10.  Scoping
> >
> >    The Tunnel Encapsulation attribute is defined as a transitive
> >    attribute, so that it may be passed along by BGP speakers that do not
> >    recognize it.  However, it is intended that the Tunnel Encapsulation
> >    attribute be used only within a well-defined scope, e.g., within a
> >    set of Autonomous Systems that belong to a single administrative
> >    entity.  If the attribute is distributed beyond its intended scope,
> >    packets may be sent through tunnels in a manner that is not intended."
> >
> > In other words, it's desirable to automatically discover the tunnel
> > encapsulation capability in a single administrative domain.
> >
> >> For IS-IS, which is under one administrative domain, having a manual
> >> config that
> >> maps administrative tags to a tunnel config seems reasonable. At the end
> >> how
> >> many tunnel types would one have in the whole network? One, maybe two.
> >> (Three gets you a call from the Ops manager)
> >
> > Let me give you an example, you have 100 nodes in a single administrative
> > domain, do you want to configure on each of them the encapsulation
> > capability of the other 99 nodes?  And when you add one router to the
> > administrative domain, do you hope to configure the tunnel encapsulation
> > capability of that new router on those 100 routers?
> >
> >>
> >> I guess it is more convenient (or we are more used to) defining new TLVs
> >> than
> >> defining what seems an implementation aspect - that IS-IS is able to map
> >> admin
> >> tags to a tunnel forward behaviour.  But is it useful?  My guess is
> >> implementations do the minimum as mentioned in section 3 of
> >> draft-xu-spring-islands-connection-over-ip:
> >>
> >>    As for which tunnel encapsulation type should be used by X, it can be
> >>    manually specified on X or learnt from Y's advertisement [...]
> >>
> >> I.e. they use a manual configuration. Maybe we should consider defining
> >> this
> >> first, so we can build simple, interoperable implementations?
> >
> > Manual configuration is workable. However, it would be more convenient if
> > the tunnel encapsulation capability could be automatically discovered.
> >
> > Best regards,
> > Xiaohu
> >
> >>
> >> Regards, Marc
> >>
> >>
> >>
> >>
> >> On Mon, 29 Feb 2016 05:33:47 +0000, Les Ginsberg (ginsberg) wrote:
> >>> Let me try to clarify my concerns...
> >>>
> >>> To use a tunnel endpoint you have to know it is reachable (IP/IPv6
> >>> Reachability TLVs already do this), you have to know it is reachable using
> >>> the underlying tunnel transport (implementations today get this from
> >>> internal communication (e.g. LDP), and you need to know it is the address
> >>> of choice. For the last, admin tag is a much more efficient means of
> >>> advertising this. For the first two this draft does not add value.
> >>>
> >>> In summary, I think what is proposed in this draft  is bloating the
> >>> advertisement space, will require more config knobs to control what is
> >>> advertised, and won't tell us anything that we could not determine using
> >>> existing infrastructure and/or additional use of admin tags.
> >>>
> >>>    Les
> >>>
> >>>> -----Original Message-----
> >>>> From: Marc Binderberger [mailto:[e-mail]]
> >>>> Sent: Sunday, February 28, 2016 7:43 PM
> >>>> To: Les Ginsberg (ginsberg); Hannes Gredler; Uma Chunduri
> >>>> Cc: [e-mail] list; Christian Hopps
> >>>> Subject: Re: [Isis-wg] WG Adoption Call for
> >>>> draft-xu-isis-encapsulation-cap
> >>>>
> >>>> Hello Les, Hannes, Uma & IS-IS experts,
> >>>>
> >>>> when I was reading the document for the first time I had a similar
> >>>> reaction:
> >>>> what is the actual problem this draft tries to solve?
> >>>>
> >>>>
> >>>>> IMO the generic ability to discover tunnel-endpoints is something
> >>>> desireable.
> >>>>
> >>>> that is a generic statement, so I agree :-)
> >>>>
> >>>>> agreed that the actual use-cases should be (better) documented
> >>>>> somewhere (perhaps in RTGWG ?), but we can do that after WG
> adoption
> >>>> as
> >>>>> well.
> >>>>
> >>>> That's where I have a problem. I prefer to have at least one use-case at
> >>>> the
> >>>> time when a proposal is under discussion. Looking at RFC5512 the
> >>>> Introduction
> >>>> chapter is more detailed. I'm not saying the list of "partial deployment
> >>>> of
> >>>> X" in the draft's section 1 is not convincing - but there are no details
> >>>> for
> >>>> at least one the items on the list.
> >>>>
> >>>>
> >>>> E.g.: I assume that not every node in the IS-IS network support a tunnel
> >>>> encapsulations - otherwise the draft may not be necessary. For the start
> >>>> Node
> >>>> R1 to reach the end Node R4 and realizing there is an MPLS/BIER/IPvX gap
> >>>> in
> >>>> between, R1 must find an egress tunnel node R2. R2 needs to find an
> >>>> ingress
> >>>> tunnel node R3
> >>>>
> >>>>           Zone 1            Zone 2              Zone 3
> >>>>     R1 -----/.../---- R2 -----/.../------ R3 -----/.../---- R4
> >>>>          has MPLS,         misses MPLS,        has MPLS,
> >>>>          BIER, IPvX        BIER or IPvX        BIER, IPvX
> >>>>
> >>>> (beware of proportional fonts - they are evil :-)
> >>>>
> >>>>
> >>>> I'm guessing that the draft does not differentiate between egress and
> >>>> ingress
> >>>> tunnel capability, i.e. if you support tunnel X you can encapsulate and
> >>>> decapsulate. Fine with that - but it's nowhere mentioned.
> >>>>
> >>>> Then there is the matter of borders, here between Zone 1 and 2, and
> >>>> between
> >>>> Zone 2 and 3. For RFC5512 this concept may be more natural as BGP is
> made
> >>>> for
> >>>> it. What are the expectations for IS-IS though? Do all routers bordering
> >>>> two
> >>>> zones need to be tunnel-capable?  Do we want to support a limited
> number
> >>>> of
> >>>> tunnel-capable border routers?  What impact does this have on the
> >> required
> >>>> TLV information, distribution etc.?
> >>>>
> >>>>
> >>>> Long story short: I find it difficult to discuss the draft without more
> >>>> context.
> >>>>
> >>>>
> >>>> Regards, Marc
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> On Sat, 27 Feb 2016 18:28:10 +0000, 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.
> >>>>>
> >>>>>    Les
> >>>>>
> >>>>>
> >>>>>> -----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-cap/
> >>>>>> |
> >>>>>> |
> >>>>>> |    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
> >>>>>
> >>>>> _______________________________________________
> >>>>> Isis-wg mailing list
> >>>>> [e-mail]
> >>>>> https://www.ietf.org/mailman/listinfo/isis-wg
> >>>>>
> >>>
> >>> _______________________________________________
> >>> Isis-wg mailing list
> >>> [e-mail]
> >>> https://www.ietf.org/mailman/listinfo/isis-wg
> >>>
> >>
> >> _______________________________________________
> >> Isis-wg mailing list
> >> [e-mail]
> >> https://www.ietf.org/mailman/listinfo/isis-wg
> >
> > _______________________________________________
> > Isis-wg mailing list
> > [e-mail]
> > https://www.ietf.org/mailman/listinfo/isis-wg
> >