1 / 17

Phil Levis, Stanford Univ. JP. Vasseur, Cisco Systems David Culler, UC Berkeley

Overview of Existing Routing Protocols for Low Power and Lossy Networks draft-levis-roll-overview-protocols-00. Phil Levis, Stanford Univ. JP. Vasseur, Cisco Systems David Culler, UC Berkeley IETF 70 ROLL WG Meeting. Goal (1).

crescent
Download Presentation

Phil Levis, Stanford Univ. JP. Vasseur, Cisco Systems David Culler, UC Berkeley

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Overview of Existing Routing Protocols for Low Power and Lossy Networksdraft-levis-roll-overview-protocols-00 Phil Levis, Stanford Univ. JP. Vasseur, Cisco Systems David Culler, UC Berkeley IETF 70 ROLL WG Meeting

  2. Goal (1) • Provide a discussion platform for building a rough consensus around the suitability, ill-suitability, and technical trade-offs in utilizing existing IETF protocols for Routing Over Low-power and Lossy networks.

  3. In pictures Future Existing Protocols “roll proto” 3. Link State Protocols 3.1. OSPF 3.2. OLSR 3.3. TBRPF … … 4. Distance Vector protocols 4.1. RIP 4.2. DSDV 4.3. AODV 4.4. DYMO 4.5. DSR . . . . … Overview ID Common understanding of basis for analyzing alternatives and rough consensus on assessment

  4. Goal (2) • Provide a discussion platform for building a rough consensus around the suitability, ill-suitability, and technical trade-offs in utilizing existing IETF protocols for Routing Over Low-power and Lossy networks. • Not to design a final protocol, but a baseline and framework for the process of defining one.

  5. Crit 0 Crit 1 Crit 2 Crit 3 … 3. Link State 3.1. OSPF 3.2. OLSR 3.3. TBRPF … 4. Distance Vector 4.1. RIP 4.2. DSDV 4.3. AODV 4.4. DYMO 4.5. DSR … Outcome Rough Consensus on the Criteria Quantitative and qualitative Rough Consensus on the Analysis

  6. Application Domain Requirements Simplifications The Technical Task … low rate … … scalability… Routing over Low-Power & Lossy Constraints Challenges Technological

  7. Preliminary Analysis Use Ctrl Routing ovhd state 3. Link State 3.1. OSPF wired O(NNdc) O(Nd) 3.2. OLSR wireless O(NN) O(Nd) 3.3. TBRPF wireless O(NN) O(Ndd) … 4. Distance Vector 4.1. RIP wired O(ND) O(D) 4.2. DSDV wireless O(NCc) O(Cd) 4.3. AODV wireless O(ND) O(D) 4.4. DYMO wireless O(NCch) O(Ch+d) 4.5. DSR wireless O(NNdh) O(Dh) … • N – nodes • C – communicating nodes • P – pairs (active routes) • D – destinations • d – degree (denisty, nbrs) • c – link churn • h – hops (diameter, route length) … just to get discussion ROLLing

  8. What’s different in ROLL?

  9. Routing • … exchange of information to establish and maintain local tables such that each node can compute • next hop, IF := R(destination) • in a manner consistent with the underlying connectivity graph IF := R(d)

  10. Wireless (nLP, nL) Routing • No a priori underlying connectivity graph • a link exists if it works when you try it • “self-organization”, discovery • Next hop is a neighbor node selection • nbr set may vary in time due environmental effects, movement, interference, obstacles, other communication, … • Topology is determined by physical placement • e.g, impact on d? …of d?

  11. Parameters (first pass) • N (Nodes): # points of interest • d (degree): density of deployment / range • max degree may be huge • h (hops): physical extent / range • c (churn): environmental factors • C (Communicators): active portion • D (Destinations): concentration of flows

  12. Constraints • Low Power • lifetime, physical size, rate of activity, cost, applicability, … all dictated by power consumption • Short range, high loss rate, small MTU, low rate links • Low (ave) data rates typical • Routing protocol rate must be << application rate • Routing protocol comm. costs matter • Discovery, maintenance, repair, … • Computed wrt deployment characteristics • N, d, h, c, C, D, …

  13. Constraints • Low Power • Footprint • microcontrollers (outnumber microprocessors 25:1) typically have kilobytes of memory, not megabytes or gigabytes. • $s • ram $0.40/kb, 100x sram, 10,000x dram • Standby power (which dominates in low duty cycle) determined by leakage • MB ram => discarded in sleep, restored on wake • All routing state matters • route tables, neighbor tables, caches, DBs, buffers • N, d, h, c, C, D • Summarization, partial information, …

  14. Challenges • Lossy • Low Transmit Power • Low SNR, short range [d?, h?] • Low sensitivity • Physical attenuation, occlusion, interference, motion • generally cannot move the node to make the network happy • Receiver diversity, in addition to temporal, frequency, spatial • loss is typical, not exceptional • often transient, not necc. excess data rate [c?] • typically, should not trigger costly repair • Loss  No Link • Reception  Link present • Multiple paths permit local rerouting • Scale is often very large

  15. Rock and ROLL • Requires rigorous routing protocol design • Can’t just throw resources at it. • Can’t just throw bandwidth at it. • Must use prolonged observation, not instantaneous. • Faces same concerns as embedded applications • ROLL operates “between a rock and a hard spot”

  16. Can we tackle such a hard problem? • Lots of existence proofs in the industry today • Application domains introduce important simplifications • The “not required” or “infrequent” is as important as the “is required” • Routing Requirement drafts are defining these • This draft represents them parametrically • Example • Vast majority of flows are in to and out of a single (or few) points [ D?, C?, P?] • Minority of mobile nodes within static extent • …

  17. Start of a Process • Important to have a analysis template to gain consensus on the relevant parameters, the criteria and the analysis across protocols • Each entry in the table will have considerable supporting evidence • Goal is common understanding of facts, not “winning the match”. • There may be no “winner” but important lessons learned from each entrant. • No “sacred cows” assumed. • Expect an active, interactive exchange between Phili and Dublin

More Related