Subject: [Raw] RAW updated charter

From: "Pascal Thubert (pthubert)" <[email-masked]>
Date: Wed, 18 Sep 2019 15:09:39 +0000

Dear all

At the meeting at IETF 105, a number of comments were discussed.

In particular,  Lou's point about whether RAW is a technology group (over foo) or a L2 agnostic IP layer thingy. As a way to program TSCH it was an over foo. As a DetNet inheritance it was IP layer. We had to choose. The discussion leaned towards an IP layer thingy, which leaves the TSCH programming out.

On the side, we had to open to other technologies but since it is hard to say that we work on *, we thought that keeping a list of focus technologies on which we can evaluate our proposals (like LPWAN does for instance) was still preferable.

Another comment was to clarify the scope. We are now clearly a specialization of DetNet. Janos indicated in a long mail that it could mean that the work should be done within DetNet. Considering the load at DetNet and the current interests, I tend to prefer a separate group with a focus, see note1 below.

On the side, we appear to be the only BoF request for Singapore https://trac.tools.ietf.org/bof/trac/wiki . We need all hands on the deck this time!

I maintain the charter here: https://trac.tools.ietf.org/bof/trac/wiki/RAW and cc'ed the current very below.

Proposed charter

---------------------

   Bringing determinism in a packet network means eliminating the statistical
   effects of multiplexing (jitter and collision loss) in the transmissions.
   Wireless networks operate on a shared medium, and thus transmissions cannot
   be fully deterministic due to uncontrolled interferences, including the
   self-induced multipath fading. However, scheduling the transmissions can
   alleviate those effects by leveraging diversity in the spatial, time and
   frequency domains, providing a more reliable and available service.

   Deterministic Networking is an attempt to mostly eliminate packet loss for a
   committed bandwidth with a guaranteed worst-case end-to-end latency, even
   when co-existing with best-effort traffic in a shared network.
   This innovation is enabled by recent developments in technologies including
   IEEE 802.1 TSN (for Ethernet LANs) and IETF DetNet (for wired IP networks).
   It is getting traction in various industries including manufacturing, online
   gaming, professional A/V, cellular radio and others, making possible
   many cost and performance optimizations.

   Reliable and Available Wireless (RAW) networking services extend DetNet
   to approach end-to-end deterministic performances in a network with
   scheduled wireless segments, possibly combined with wired segments, and
   possibly sharing physical resources with non-deterministic traffic.
   The wireless and wired media are fundamentally different at the physical
   level, and while the generic Problem Statement for DetNet applies to the
   wired as well as the wireless media, the methods to achieve RAW have to
   differ from those used to support time-sensitive networking over wires, as
   a RAW solution will need to address less consistent transmissions, energy
   conservation and shared spectrum efficiency.

   The development of RAW technologies has been lagging behind deterministic
   efforts for wired systems both at the IEEE and the IETF. But recent efforts
   at the IEEE and 3GPP indicate that wireless is finally catching up at the
   lower layer and that it is now possible for the IETF to extend DetNet for
   wireless segments that are capable of scheduled wireless transmissions.

   The intent for RAW is to provide DetNet elements that are specialized for
   short range radios. From this inheritance, RAW stays agnostic to the radio
   layer underneath though the capability to schedule transmissions is assumed.
   How the PHY is programmed to do so, and whether the radio is single-hop
   or meshed, are unknown at the IP layer and not part of the RAW abstraction.

   Still, in order to focus on real-worlds issues and assert the feasibility of
   the proposed capabilities, RAW will focus on selected technologies that can
   be scheduled at the lower layers: IEEE Std. 802.15.4 timeslotted channel
   hopping (TSCH), 3GPP 5G ultra-reliable low latency communications (URLLC),
   IEEE 802.11ax/be where 802.11be is extreme high throughput (EHT), and L-band
   Digital Aeronautical Communications System (LDACS) -see Note1-.

   The establishment of a path is not in-scope for RAW. It may be the product of
   a centralized Controller Plane as described for DetNet. As opposed to wired
   networks, the action of installing a path over a set of wireless links
   may be very slow relative to the speed at which the radio conditions vary,
   and it makes sense in the wireless case to provide redundant forwarding
   solutions along a complex path and to leave it to the RAW Network Plane to
   select which of those forwarding solutions are to be used for a given packet
   based on the current conditions.

   The path installed by the Controller Plane should provide a high degree of
   radio redundancy and diversity (DetNet PREOF, end-to-end network coding, and
   possibly radio-specific abstracted techniques such as ARQ, overhearing,
   frequency diversity, time-slotting, and possibly others). The goal of the RAW
   operation is to control redundant transmissions along a path at the
   forwarding timescale to maintain the expected service level while optimizing
   the usage of constrained resources such as energy and spectrum.

   The scope of the RAW WG comprises Network plane protocol elements such as OAM
   and in-band control to enable the RAW operation at the Service and at the
   forwarding sub-layers, e.g., controlling whether to use packet replication,
   Hybrid ARQ and coding, with a constraint to limit the use of redundancy when
   it is really needed, e.g., when a spike of loss is observed. RAW observes the
   path in quasi real-time. The WG will consider the applicability of existing
   tools -see Note2- such as L2-triggers, DLEP -see Note3-, BFD and in-band-OAM
   to observe the path, and BIER-TE and Segment Routing to control the use of
   the path on individual packets.

   RAW forwarding decisions may be made at the ingress and signaled in-band.
   Alternatively, they may be made at intermediate hops and depend on the state
   of the next hop and local policies, in which case a different in-band
   signaling may be needed.

   The group will produce the following deliverables -see Note2-:

      1) An informational document describing deterministic wireless
         use cases, in continuation to the DetNet Use Cases document

      2) An informational document describing the technologies that the
         group will cover (e.g., URLLC, TSCH, 802.11ax/be and possibly LDACS)

      3) Produce a Standards Track document to enable operations,
         administration and maintenance (OAM) inside a RAW network, providing
         packet loss evaluation, self-testing and automated adaptation to
         enable trade-offs between resilience and energy consumption.

   Note1:
   The Working Group will leverage cross-participation with the associated set
   of stakeholders to ensure that the work taking place corresponds to real
   demands and that the proposed solutions are indeed applicable. Participants
   coming from the wireless industry are not expected to be familiar with the
   IETF nor interested with the current DetNet activities on pseudowires and
   MPLS. It makes sense to provide them with a separate WG were attendees
   can talk a same language with folks that share a common interest.

   Note2:
   A problem statement and one or more applicability statements will be produced
   that may or may not be suited for archiving, to be decided at a later time.

   Note3:
   As a technique to provide a radio-specific DetNet service and forwarding
   sub-layers, RAW appears to belong to the routing Area. Overlaps with MANET
   were identified (e.g., the use of DLEP), but as an approach towards
   Deterministic Networking, RAW is neither mobile nor ad-hoc, but pretty much
   the very opposite.

Comments welcome as usual !

Pascal