Why do we need a routing solution for Low Power And Lossy Networks (L2Ns) Is it too early or already too late ? Routing Area Meeting - IETF-69 JP Vasseur/David Culler

“What are L2Ns ?” L2Ns: Networks comprising a large number of highly constrained devices interconnected by wireless links of unpredictable quality

Why are L2Ns so important … “This is Obvious” (Ross) Enable New Knowledge Improve Productivity Healthcare Improve Food & H20 Energy Saving (I2E) Preventing Failures Enhance Safety & Security High-Confidence Transport Heal th Smart Home

Is there a problem here ? So what? – New class of applications – New tier of devices – Networks move the bits Can we just consider L2Ns as “regular” IP networks and use existing protocols ?

What make L2Ns so special ? Current Internet An IGP has typically few hundreds of nodes, Links and nodes are stable, Nodes constraints or link bandwidth are typically non issues. L2Ns An order of magnitude larger in term of number of nodes, Links are highly unstable and Nodes die much more often, Unique requirements (see next slides)

Unique Routing Requirements L2Ns Highly constrained devices Harsh & dynamic environments: (variable link qualities, link/nodes fail at a rate significantly higher than within the Internet) Small MTU (high error rate, limited buffer/bw) Constraint routing is a MUST: take into account link *and* nodes properties and constraints (also unusual) Routing in L2Ns is a MUST for energy saving (short distances => less energy to transmit) *and* to route around obstacles (including poor quality links),

Deep power management: WSN in sleep mode most of the time Highly heterogeneous capabilities Structured traffic patterns: P2MP, MP2P but also more and more P2P Unique Routing Requirements L2Ns (Cont)

Multi-path and asymmetrical load balancing Data aware routing: data aggregation along a dynamically computed path to a sink. Self-Managed !! Unique Routing Requirements L2Ns (Cont)

Why can’t we use an existing routing protocol ? Many IP routing protocols have been designed: RIP, OSPF, AODV, OLSR, DYMO, TBRPF But … As pointed out Routing requirements for L2Ns are unique, None of them satisfy the minimum set of requirements, Some of them could be adapted/twisted/… but that means major protocol rework.

What about MANEMO ? Problem: Mobile Ad-Hoc NEMO, enable a L3 mesh of NEMO mobile routers that optimizes local and global reachability. Quite different problem spaces. There are commonalities but also lots of differences (level of constraints, P2P, …), May lead to common routing protocol solutions, RSN could be fed by MANEMO requirements and see whether the protocol designed for L2Ns could be accommodated (WITHOUT losing the focus).

Suggested approach: do not design solutions for all L2Ns Research has focused on near-optimal solutions to the specific problems IP is maximizing interoperability, not aiming at finding a local optimum ;-)

Standardization status New applications pretty much every day … but … The number of proprietary solutions literally explodes: Zigbee, Z-Wave, Xmesh, SmartMesh/TSMP, SP100, …) at many layers (physical, MAC, L3) and most chip vendor claim to be compatible with their own standard Various protocol (L1/L2) to be reused such as , , WiMax, …

So what are the options ?

Internet L2N TrueMesh Wireless HART ISA SP100.11a Xmesh Znet MintRoute MultiHop LQI CENS Route Smart mesh TinyAODV Honeywell What the Internet will soon look like Do Nothing …

Issues ? Internet We know all of this from the 80’ and 90’ * Management complexity * Lack of end to end consistency in term of routing, QoS, management, security, … * Remember SNA, IPX, Vines, … or IP over ATM/FR, … ? Multi-protocol Gateway (IP-proxy, protocol translations) L2N

Or … IP end to end Internet IP router ! L2N

IETF: Standardization status 6LoWPAN (to be re-chartered soon to extend the scope and work on discovery, management, security, …) 6LoWPAN WG consensus (today): L2/L3 agnostic requirements to be worked within 6lowpan and potentially given to RL2N. RL2N (Routing for Low Power and Lossy Networks): new mailing list where the routing issues are discussed. Several large players have joined the initiative:

IETF: Standardization status In the works: Routing Requirements for L2Ns: draft-culler-rl2n- routing-reqs-01 Routing Requirement ID for Connected Home: draft-brandt-rl2n-home routing-reqs Routing Requirements ID for Industrial applications: in the works Survey on existing routing protocol applicability: draft-levis-rl2n-overview-protocols Routing metrics for RL2N: in the works

Key take-away … Stating Facts: –L2Ns are being deployed using proprietary protocols: the need is there. –L2Ns routing requirements are unique. So … Does the IETF community agree that we should be having a WG focusing on routing issues for L2Ns ?

Thanks.