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NWCRG-IAB-Review-IETF91.pdf
- 1. Network Coding Research Group (NWCRG) Overview IAB Review 13 November 2014 Brian Adamson Victor Firoiu
- 2. Network Coding •Network coding is a method of opHmizing the flow of digital data in a network by transmiMng digital evidence about messages ... • PotenHal benefits for – Capacity – Robustness – Security – Energy efficiency Bu#erfly Example
- 3. MoHvaHon for NWCRG • Research proved performance gains and pracHcal algorithms – From: Netcoding mulHcast achieves max flow-‐min cut – To: Coding scheme for reliable communicaHon over packet networks – To: results in capacity of wireless networks using network coding – And many others – Much research remains to be done. • Mature ImplementaHons – Full network coding systems have been demonstrated – Network coding has begun “popping up” in various IRTF, IETF, and other forums – More general applicability and opportunity seen with new paradigms such as InformaHon Centric Networking and Soware Defined Networking 3
- 4. Open Research Areas • Aspects of packet network systems – Control, RouHng / forwarding, Transport, Physical layers • How can network coding be effecHvely and pragmaHcally applied to a scalable, distributed network like the Internet? – CongesHon control, End vs. Intermediate System, Edge (wireless) • Where does network coding provide benefit? • Architecture, operaHon and applicaHons – End-‐to-‐end vs. hop-‐by-‐hop – Intra-‐flow and inter-‐flow – ApplicaHon-‐layer use – Service paradigms: Best Effort, Content, MulHmedia
- 5. Candidate Areas for standardizaHon (longer term) • Common encoding algorithms • Protocols: – Network Coding Transport – RouHng: subgraph construcHon – Forwarding on subgraphs • Service descripHons • Packet formats
- 6. Current AcHviHes and Approach • InformaHon exchange – Coding techniques – Protocol concepts – Use cases • Taxonomy and architecture development – AdempHng to derive a building block approach from key use cases and idenHfiable funcHonal areas
- 7. Building Blocks Applica0ons Prior Example: RMT Building Block Approach TFMCC PGMCC* WEBRC Reed Solomon Security NACK FEC Raptor(Q) LDPC NORM ALC FCAST FLUTE LCT Protocol Instan0a0ons TRACK* GRA* * Unrealized building blocks No-‐Code
- 8. Network Coding SystemDecomposition 8 System Func0onal Area 1 Func0onal Area 2 Func0onal Area ‘N’ Buildin g Block Buildin g Block Buildin g Block Buildin g Block
- 9. Network Coding UseCases 1. NC shim* layer - under TCP, UDP, SSH 2. NC transport, in-network coding 3. NC transport over overlay network 4. NC shim* under tunnel (MPLS, IPsec) 5. Coded TCP (or TCP-like) over disjoint paths 6. NC content dissemination at application layer (*) Shim: usually between routing and transport Note: This is not an exhaustive list, but hopefully a large enough set to help identify key building blocks that can be reapplied for different use cases. 9
- 10. M-‐path Fwd M-‐path Fwd M-‐path Fwd MulH-‐path RouHng Use Case 2: NC Transport, In-‐Network Coding 10 App NC Coding NC Cong Ctrl NC Transport NC Reliability IP IP App NC Coding NC Cong Ctrl NC Transport IP NC Reliability Coding vectors, coded pkts Feedback Cong. signals App data Rate control Coded symb, Rank test NC Cod NC CC NC Transport NC Rel Up/down neighbors Splitting ratios Link quality MulH-‐path RouHng MulH-‐path RouHng IP • Assisted by mulH-‐path (subgraph) rouHng • Usage: reliability, resilience to link and node outage. • Supports both Unicast and MulHcast
- 11. Network Coding FunctionalAreas • NC Coding – All coding operations • NC Reliability – Data and control to support reliable transfer • NC Congestion Control – Controls transmission rates – Try to use existing algorithms • Multi-path routing, multi-path forwarding – How network coding is distributed over network from source(s) to destination(s) • Security – First option: rely on existing solutions – Coding can be used for pollution detection and correction, anonimization, protection against denial of service 11
- 12. Network Coding RG AcHviHes • Chartered on 2013-‐11-‐13 • ~28 research presentaHons over 4 meeHngs • Network Coding Taxonomy, now an RG dra dra-‐irk-‐nwcrg-‐network-‐coding-‐taxonomy-‐00 • Individual dras dra-‐amdouni-‐nwcrg-‐cisew-‐00 dra-‐detchart-‐nwcrg-‐tetrys-‐00 dra-‐khasnabish-‐nwcrg-‐impact-‐of-‐vir-‐and-‐sdn-‐02 • Proposal for a Network Coding Architecture • Planned: Network Coding Tutorial dra
- 13. Issues and MiHgaHon • IPR: Some aspects (coding, etc) have IPR claims – Reminders and follow-‐ups to file disclosures – Architecture open to full range of algos • Need for interacHon with other IRTF research groups and/or IETF working groups – Build stronger awareness, parHcipaHon within NWCRG • Current emphasis on end-‐to-‐end transport – Encourage consideraHon of richer network coding approaches
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- 15. NWCRG MoHvaHon: Research Advances Research proved performance gains and pracHcal algorithms • Ahlswerde et al, 2000 – Network coded mulHcast achieves max flow-‐min cut • S Li et al 2003 – Linear coding w/ finite symbol size-‐ sufficient for mulHcast • Koeder, Medard 2003 – Algebraic framework for linear network-‐coding – Min-‐cut max-‐flow achieved w Hme-‐invariant soluHons for networks with delay and cycles. • Ho et al 2003 – Distributed randomized network coding • Lun et al 2005 – coding scheme for reliable transport over packet networks • And many others. Much research remains to be done.
- 16. Use Case 1: NC Shim Layer – under TCP, UDP, SSH 16 Unicast RouHng Unicast RouHng Unicast RouHng TCP App NC Coding NC Cong Ctrl NC shim NC Reliability IP IP IP TCP App NC Coding NC Cong Ctrl NC shim NC Reliability Coding vectors, coded pkts Feedback (rank, null space) Congestion signal, Backlog size Congestion signal, Recv window App data Rate control Coded symbols, Rank test • Coding: end-‐end. Passes CC signaling. • OpHonal: in-‐network re-‐coding. • Coding nodes determined by: staHc configuraHon, rouHng or control signaling. • Usage: reliability, similar to source coding.
- 17. Overlay RouHng Use Case 3: NC Transport over Overlay Network 17 App NC Coding NC Cong Ctrl NC Transport NC Reliability IP IP App NC Coding NC Cong Ctrl NC Transport IP NC Reliability Coding vectors, coded pkts Feedback Cong. signals Rate control Coded symb, Rank test NC Cod NC CC NC Transport NC Rel Up/down neighbors Splitting ratios Coded pkts, Select link Overlay Fwd UDP UDP Overlay RouHng Overlay Fwd UDP UDP Overlay link Overlay RouHng Overlay Fwd UDP UDP • Overlay links can be reliable (TCP) or unreliable (UDP). • Requires both reliability and congesHon control funcHons • Usage: reliability, resilience to link and node outage, anonymity.
- 18. Use Case 4: NC Shim under Tunnel (MPLS, IPsec) 18 TCP/ UDP App NC Coding NC Cong Ctrl NC shim NC Reliability IP IP NC Coding NC Cong Ctrl NC shim NC Reliability Coding vectors, coded pkts Feedback (rank, null space) Congestion signal, Backlog size Rate control Coded symbols, Rank test TCP/ UDP App MPLS Tunnel Configured routes IP IP Configured routes Tunnel 1 Tunnel 2 TCP/ UDP App TCP/ UDP App MPLS Tunnel • Usage: Provides reliable forwarding under MPLS tunnel • Assumes configured IP tunnels or routes under NC shim
- 19. Use Case 5: Coded TCP (or TCP-‐like) over Disjoint Paths 19 • Coding: over all paths • CongesHon control: separate for each path NC Coding NC Reliability IP IP NC Coding Coding vectors, coded pkts Feedback (rank, null space) Coded symbols, Rank test IP IP Tunnel 1 or Netw 1 (eg LTE) Tunnel 2 or Netw 2 (eg, WiFi) MPTCP App TCP TCP NC Rel* NC Rel* NC Reliability TCP TCP NC Rel* NC Rel* (*) optional MPTCP App Or NC Cong Ctrl Or NC Cong Ctrl Or NC Cong Ctrl Or NC Cong Ctrl