doc.: IEEE 802.15- Project: IEEE P802.15 Working Group

doc.: IEEE 802.15-<15-13-0685-01-wng0> Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [6TiSCH + 802.1 for a new IPv6 MultiLink subnet] Date Submitted: [12 November 2013] Source: [Pascal Thubert] Company [Cisco] Address [[email protected]] Re: [Presentation to 802.15 WNG] Abstract: [Discuss IETF 6TiSCH Architecture and potential collaborations.] Purpose: [Generate/focus activity on large Scale IPv6 multilink subnets federating 802.15.4e meshes.] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Submissio

n Slide 1 , doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH + 802.1 + 802.15.4 A new IPv6 MultiLink subnet Submissio n Slide 2 ,

doc.: IEEE 802.15-<15-13-0685-01-wng0> The Case for Deterministic Wireless Cables can be inappropriate for rotating devices, moving cranes, robots arms or mobile handheld devices Cables are expensive Wire buried in conduit has high installation and maintenance cost, long lead time and extreme difficulties to repair 1% improvement leads to $15M/year in just 1 refinery Better process optimization and more accurate predictive maintenance increase profit Thus more and different sensors can be justified economically, if they can be connected Submissio

n Slide 3 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Industrial connected device growth Submissio n Slide 4 ,

doc.: IEEE 802.15-<15-13-0685-01-wng0> IPv6 to address and manage devices Submissio n Slide 5 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Industrial Landscape Submissio n

Slide 6 , doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH Approach to Wireless Deterministic Networks Submissio n Slide 7 ,

doc.: IEEE 802.15-<15-13-0685-01-wng0> Current architecture: isolated networks Submissio n Slide 8 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Step 1, 6TiSCH Subnets connected to carpeted floor

Submissio n Slide 9 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Step 2, Multilink Subnet enables unhindered mobility Submissio n Slide 10 ,

doc.: IEEE 802.15-<15-13-0685-01-wng0> Benefits For Users A step toward Harmonization (Hour Glass model) COTS price, Standard experience (e.g. crypto), IPv6 end to end, enabling virtualization, thus easier install and mgnt Deterministic to the carpeted floor, enabling control loops with virtual PLC For Vendors Extends value proposition, less dedicated hardware, more software Extends the reach of IP technology, save on generic soft and hard

components Reusable Improvements on generic capabilities (e.g. deterministic switching) App Servers in the control loop, revenue from VSE, routing and analytics Submissio n Slide 11 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Challenges Network Configuration and Access Control Autonomic Behavior

Critical applications End-to-End determinism Scheduling L2+L3 Network AND virtualized devices Operation Scaling IPv6 Subnets by 2 orders of magnitude Issues with link local multicast in discovery protocols even on high speed links (IPv6 Neighbor Discovery, mDNS, Bonjour) DataCenters dissatisfaction (ARMD) answered by Overlay approaches (LISP, NVO3 ) Submissio n Slide 12 , doc.: IEEE 802.15-<15-13-0685-01-wng0>

6TiSCH in a nutshell Submissio n Slide 13 , doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH Charter and matching activity Deterministic IPv6 over IEEE802.15.4e TimeSlotted Channel Hopping The Working Group will focus on enabling IPv6 over the TSCH mode of the IEEE802.15.4e standard. The extent of the

problem space for the WG is one or more LLNs, eventually federated through a common backbone link via one or more LLN Border Routers (LBRs). Active drafts Submissio n Slide 14 , doc.: IEEE 802.15-<15-13-0685-01-wng0> TSCH properties Channel Hopping : retry around interference, round robin strategy Time Slotted (or Synchronized) : Deterministic: through TDM, Synchronized + Time formatted in SlotFrame(s) Tracks: below IP, can be orchestrated by a third party like

virtual circuits Slotted: benefits of slotted aloha vs. aloha => reduce chances of collisions Battery operation: when traffic profile is known, devices only wake upon need Submissio n Slide 15 , doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH: IPv6 over 4e TSCH MAC Active IETF WG, 4 WG docs being adopted Define an Architecture that links it all together Align existing standards

(RPL, 6LoWPAN, PANA, RSVP, PCEP, MPLS) over 802.15.4e TSCH Support Mix of centralized and distributed deterministic routing Design 6top sublayer for L3 interactions Open source implementations (openWSN) Multiple companies and universities participating Submissio n Slide 16 , doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH Client stack

Submissio n Slide 17 , doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH-based Multilink Subnet Submissio n Slide 18 ,

doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH Requirements and Problems Submissio n Slide 19 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Scalability requirements

10s of thousands of LLN devices Classical + Virtual devices attached to backbone Individual IPv6 addresses visible over backbone Aggregation at the Backbone router not expected Classical IPv6 ND uses flooding to feed neighbor cache Most hosts only connect to a few other nodes Servers, routers, and firewalls connect to many Submissio n Slide 20 ,

doc.: IEEE 802.15-<15-13-0685-01-wng0> Single IPv6 Subnet requirements 10s of Ks devices with multihop LLN access No broadcast in the LLNs No renumbering (quasi permanent IPv6 address) Continuous reachability as a LLN device moves in Subnet Radio conditions change cause network reorganisation Already use cases such as handheld, cranes, small vehicles Backward Compatibility with classical IPv4 and v6 devices Support of discovery protocols throughout the subnet Submissio n Slide 21

, doc.: IEEE 802.15-<15-13-0685-01-wng0> Routing requirements Cost Optimized in the backbone Any to any traffic Multipath and load balancing a bonus Power Optimized in the LLNs Most traffic flows to or from the LLN Backbone Router Control traffic must be limited vs. Data traffic Broadcast or scalable multicast in the backbone Multicast or Controlled dissemination in the LLN Submissio n

Slide 22 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Deterministic requirements LLNs Time synchronization via the backbone to keep all LLNs in sync and allow movement from one LLN to the next Slow deterministic LLNs (proces control) No need for Deterministic backbone Until scale and congestion loss becomes an issue Upcoming faster deterministic wireless (factory automation)

deterministic loops across networks and server OS Submissio n Slide 23 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Compatibility requirements End-to-End Deterministic Standard time exchange, common precision. Sync and schedule with the Deterministic backbone MTU size a complex issue across networks Ideally harmonize MTUs across multilink subnet or at least detect discrepancies

Link Local lookups should be emulated Proxy operation (per protocol) Genralized hash based multicast Submissio n Slide 24 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Pb1: Use AND implementation of multicast 1. IPv6 Discovery protocols use multicast flooding Assuming a lower layer multicast support Not just IPv6 NDP but also mDNS, etc 2. Layer-2 destination set to 3333XXXXXXXX

3. Layer-2 fabric handles as broadcast (all nodes) 4. Broadcast clogs the wireless access at low access speed (typically 1Mbps) on all APs around the fabric 5. Broadcast self interferes on attached wireless mesh and drains the batteries on all nodes Submissio n Slide 25 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Flooding for IPv6 Neighbor Discovery Submissio

n Slide 26 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Flooding for IPv6 Neighbor Discovery Packet comes in for 2001:db8::A1 1. Router looks up ND cache (say this is a cache miss) 2. Router sends NS multicast to solicited-node multicast @ mapped in this case to 3333 FF00 00A1 1. Targets answers unicast NA 2. Target revalidates ND cache for the router, usually unicast 3. Router creates ND cache entry Routers have large caches and hosts very small ones

Submissio n Slide 27 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Flooding for mobility Submissio n Slide 28 ,

doc.: IEEE 802.15-<15-13-0685-01-wng0> Flooding for mobility VM, NFV,Wireless or IoT device moves: 1. 2. 3. 4. 5. MAC address reachability flooded over L2 switch fabric Device sends RS to all routers link scope multicast Router answers RA (u or m) Device sends mcast NS DAD to revalidate its address(es) Device sends mcast NA(O) All these steps can be checked for better efficiency Submissio

n Slide 29 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Problem2: cross-domain operations 1. 2. 3. 4. 5. Time synchronization (different precision, propagation) MAC frames (different MTU, MAC address, header info) End-to-End deterministic track setup (cross layer TSN)

Multicast and flooding implemented differently Broadcast self interfering on attached wireless mesh and drains the batteries A number of functionalities are implemented in products to prune some of those flooding with some degree of interference with the protocol operation. Submissio n Slide 30 , doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH-related

Collaboration opportunities Submissio n Slide 31 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Current 6TiSCH model Submissio n Slide 32

, doc.: IEEE 802.15-<15-13-0685-01-wng0> Case for Layer-2 Backbone L2 Routing optimizes any-to-any (all set) Integration of existing IPv4 and IPv6 hosts IPv6 ND and ARP over limited size broadcast domains TBD: Avoid leaking LLN MAC addresses IPv6 proxy ND operation for attached LLNs IPv6 aggregation and routing at the Backbone Router Possible work items: Highly scalable multicast routing to support discovery MTU harmonization and Time synchronization Submissio

n Slide 33 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Case for L3 Attached LLNs L3 Abstracts Complex LLNs Multiple PHYs, very different properties End-to-end path optimization vs. Sequence of L2 paths. Cost and latency of the backbone usually negligible RPL (RFC 6550) designed for Fringe Networking Optimized for traffic to/from the backbone. Objective Functions to adapt to any MAC/PHY

Low Power Lossy Networks fringe Incompatible with flooding no broadcast (sleeping node + energy constraints) Multicast routing done in RPL (using unicast replications) Controlled dissemination done in MPL (gossiping technique based on trickle) Possible work items: Wireless ND to proxy IPv6 ND for LLN attached devices 802.15.4 Objective Function defined at IEEE Submissio n Slide 34 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Case for X-SDO multicast

IPv6 link scope multicast addresses mapped to 3333XXXXXXXX Layer-2 address In particular solicited-node in IPv6 ND 3333FFXXXXXX => 2^24 groups Discovery Protocols (e.g. mDNS) to make good use of that space L2 to manage multicast operation using portion of the 4 octets More used bits => more multicast state, less wasted deliveries RPL can carry multicast registrations to/from the backbone Could extend in similar L2 operation over the backbone Submissio n Slide 35 , doc.: IEEE 802.15-<15-13-0685-01-wng0>

Case for X-SDO reservation / forwarding 6TiSCH supports G-MPLS forwarding L3 routing Hybrid for 6LoWPAN fragments Setup is still TBD: Need to set up multihop tracks IETF has RSVP, NSIS, LDP IEEE 802.1 working on TSN End-to-end determinism Submissio n Slide 36 ,

doc.: IEEE 802.15-<15-13-0685-01-wng0> 6TiSCH Approach The vision Submissio n Slide 37 , doc.: IEEE 802.15-<15-13-0685-01-wng0> Direction: IT/OT convergence Requires new, higher-end paradigm Reaching more devices and data, farther, cheaper

Guaranteed bandwidth + Optimum Capacity Scalable, IPv6 Multilink Subnet abstraction MUST provide High availability, flow isolation, security, Deterministic guarantees for critical applications Unhindered Mobility for Wireless Devices Making Convergence Happen Learn from Industrial, Air and Space IEEE + IETF to replicate and generalize with open standards Cooperate to share and optimize with mission specific SDOs Submissio n Slide 38 ,

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