Re: [Lsvr] Initiating LSVR re-chartering discussion - draft#1 proposal

[Greg Mirsky <[e-mail]>]

Hi Gunter,
thank you for the clarification. Because this is a WG charter, it seems
that using the terminology most of us interpret in the same manner is even
more important. Personally, I can recall the "liveness" being used the most
in RFC 5880 Bidirectional Forwarding Detection (BFD)
<https://datatracker.ietf.org/doc/html/rfc5880>. RFC 8029
<https://datatracker.ietf.org/doc/html/rfc8029> only once refers to
liveness. Perhaps we can find a bit more on the intended interpretation of
liveness in the proposed update (I guess that it will lead to new work by
the WG).

Regards,
Greg

On Wed, Dec 6, 2023 at 3:47 AM Gunter van de Velde (Nokia) <
[e-mail]> wrote:

> Hi Greg,
>
>
>
> [contributor hat on]
>
> Not sure that this is the type of liveness detection Randy had in mind for
> L3DL. I vaguely recall that supporting technology (e.g. BFD) should be used
> to detect neighbor down situations, where L3DL was used to detact the
> neighbor, that the link is alive and what L3 properties are to be used
> between the neighbors.
>
>
>
> G/
>
>
>
>
>
> *From:* Lsvr <[e-mail]> *On Behalf Of *Greg Mirsky
> *Sent:* Tuesday, December 5, 2023 3:30 PM
> *To:* Gunter van de Velde (Nokia) <gunter.van_de_velde=
> [e-mail]>
> *Cc:* [e-mail]; Ketan Talaulikar <[e-mail]>; Randy Bush
> <[e-mail]>
> *Subject:* Re: [Lsvr] Initiating LSVR re-chartering discussion - draft#1
> proposal
>
>
>
>
>
> *CAUTION:* This is an external email. Please be very careful when
> clicking links or opening attachments. See the URL nok.it/ext for
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>
>
>
> Hi Gunter et al.,
>
> thank you for sharing the proposed updated charter. As noted, a new work
> on "Layer-3 Discovery and Liveness (L3DL) protocol" is proposed. I assume
> that the liveness detection may use a BFD-like mechanism (RFC 5880
> <https://datatracker.ietf.org/doc/html/rfc5880>, RFC7880
> <https://datatracker.ietf.org/doc/html/rfc7880>). An important
> characteristic of that mechanism to note is that the monitored path would
> be considered operational even in the case of losing N-1 consecutive test
> packets, where N is pre-configured parameter, usually 3 is used. Thus, if
> two out of three test packets are lost, the monitored for liveness link is
> considered operational. Would a link with the significant packet loss rate
> be usable for an operation in the DC? Could the L3DL also include the
> performance measurement and the verification of performance metrics
> conformance? If that is the case, perhaps adding "Performance Measurement"
> in L3DL can be discussed.
>
>
>
> Regards,
>
> Greg
>
>
>
> On Tue, Dec 5, 2023 at 2:49 AM Gunter van de Velde (Nokia)
> <gunter.van_de_velde=[e-mail]> wrote:
>
> Hi LSVR WG,
>
> We would like to initiate the convergence towards a first LSVR charter
> update.
> During IETF LSVR118 WG session there was consensus we should initially
> embrace the L3DL work, and
> consider additional enhancements in a later follow-up charter update
>
> Look for the embedded L3DL text <new>text</new> .
>
> Thoughts, suggestions and constructive feedback on the draft#1 charter
> proposal is appreciated.
> If necessary we could setup an interim to discuss detailed nuances.
>
>
> **********DRAFT#1**********
>
> Charter for Working Group
>
> Data Centers have been steadily growing to commonly host tens of thousands
> of end points, or more,
> in a single network. Because of their topologies (traditional and
> emerging), traffic patterns, need for fast
> restoration, and for low human intervention, data center networks have a
> unique set of requirements
> that is resulting in the design of routing solutions specific to them.
>
> The Link-State Vector Routing (LSVR) Working Group is chartered to develop
> and document a
> hybrid routing protocol utilizing a combination of link-state and
> path-vector routing
> mechanisms <new> and the Layer-3 Discovery and Liveness (L3DL) protocol to
> discover IP Layer-3 attributes
> of links, such as neighbor IP addressing, logical link IP encapsulation
> abilities, and link liveness </new>.
> The LSVR WG will utilize existing IPv4/IPv6 transport, packet formats and
> error handling of BGP-4 consistent
> with BGP-LS NLRI encoding mechanisms (
> https://datatracker.ietf.org/doc/rfc7752/) to facilitate Link-State
> Vector (LSV) routing information distribution. An LSV is intended to be
> specified as a data structure
> comprised of link attributes, neighbor information, and other and other
> potential attributes that can
> be utilized to make routing decisions.
>
> The LSVR specification is initially focused on operation within a single
> datacenter (DC) as a single distribution
> domain, which is defined as a set of participating nodes in a single
> administrative domain. Routing protocol
> functionality defined by LSVR would be typically routing within a
> datacenter's underlay routing plane. The
> work will include coexistence considerations with BGP IPv4/IPv6 unicast
> address families installing
> and advertising routes into the same RIB.
>
> <new>The L3DL protocol is developed to discover link IP Layer-3 attributes
> and is focused upon discovering
> mutually supported layer-3 encapsulations for IP and/or MPLS interface
> addressing. The discovery protocol
> must present this data to BGP-SPF so that topology and routing tables can
> be build. L3DL should provide
> support for authenticity verification of protocol messages and provide a
> mechanism for Layer-2 keep-alive
> messaging to support session continuity, and finally support build-up for
> Layer-3 link liveness such
> as BFD.</new>
>
> The WG will consider the effects (if any) of deploying the LSVR protocol
> while concurrently using the same
> transport session as other existing BGP address families. These
> considerations will be documented as part
> of the main protocol specification. A mechanism to be able to
> independently deploy LSVR from other
> address families may be defined (as needed).
>
> The LSVR protocol is intended as a self-standing routing protocol even if
> using existing BGP transport
> mechanisms and encodings, or if sharing the same transport session with
> other existing BGP address
> families. Similar as existing routing protocols, the LSVR protocol will
> not internally combine the route
> selection mechanisms or share routing information, except through common
> external interaction
> methods in the RIB.
>
> In order to achieve the noted objective, the working group will focus on
> standardization of protocol
> functionality, defining Link-State Vectors (LSVs) and defining standard
> path-vector route selection
> utilizing the Dijkstra SPF based algorithm, BGP-4 protocol mechanics and
> BGP-LS NRLI encoding.
>
> The working group will provide specifications to manage routing
> information from other unicast
> routing protocols or BGP address families to common prefixes.
>
> The LSVR WG is chartered to deliver the following documents:
> . Specification document describing LSV with standard Dijkstra SPF
> route/path selection (calculation)
> utilizing existing BGP protocol baseline functionality and BGP-LS packet
> encoding formats
> . Specification documenting protocol extensions required to efficiently
> reuse BGP to distribute
> LSVs within an IPv4/IPv6 DC with scope to include privacy and security
> considerations
>         o The impact of these extensions to the security properties of BGP
> will be studied and documented
>         o New attack vectors will be explored and documented
>         o Mitigations to any new attack vectors identified will be
> discussed and documented
> <new>
> . Specification documenting L3DL  protocol considering usage with BGP-SPF
>         o A base protocol documenting Layer-3 Discovery and Liveness
> protocol
>         o Protocol extensions documenting Layer-3 Discovery and Liveness
> Signing
>         o Protocol extension to communicate the parameters needed to
> exchange inter-device
>         Upper Layer Protocol Configuration for upper-layer protocols such
> as the BGP family L3DL
>         Upper-Layer Protocol Configuration
> </new>
> . Applicability Statement for the use of LSVR in the Datacenter
> . YANG model specification for LSVR management
> . YANG model specification for L3DL management
>
> The WG will closely collaborate with the idr WG. Any modifications or
> extension to BGP that will not
> be specifically constrained to be used by LSVR must be carried out in the
> idr WG, but may be done in this
> WG after agreement with all the relevant chairs and the responsible Area
> Directors.
>
> (revision proposal) Milestones:
> . Mar 2024      Applicability statement for LSVR in DCs
> . Mar 2024      LSV distribution using BGP transport
> . Mar 2024      LSVR with standard Dijkstra path selection
> . Dec 2024      YANG specification for LSVR
> . <new>Jul 2024        Layer-3 Discovery and Liveness
> . Jul 2024        Layer-3 Discovery and Liveness Signing
> . Jul 2024        L3DL Upper-Layer Protocol Configuration
> . Dec 2024      YANG specification for L3DL</new>
>
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