Successfully reported this slideshow.

Can today’s Internet protocols deliver URLLC?

2

Share

Vodafone Proprietary classified as C1 - Public
Kevin Smith, Vodafone, ETSI NGP Chair
URLLC, London, November 2017
We need ...
Vodafone Proprietary classified as C1 - Public
Ethernet
Vodafone Proprietary classified as C1 - Public

YouTube videos are no longer supported on SlideShare

View original on YouTube

1 of 31
1 of 31

More Related Content

Related Books

Free with a 14 day trial from Scribd

See all

Can today’s Internet protocols deliver URLLC?

  1. 1. Vodafone Proprietary classified as C1 - Public Kevin Smith, Vodafone, ETSI NGP Chair URLLC, London, November 2017 We need to talk about TCP/IP… I demand URLLC!
  2. 2. Vodafone Proprietary classified as C1 - Public Ethernet
  3. 3. Vodafone Proprietary classified as C1 - Public
  4. 4. Vodafone Proprietary classified as C1 - Public Networking protocols have great responsibility! • Any flaws in protocol design increase network processing • Workarounds increase processing and transmission: and hence latency and cost • Design parameters must reflect current scenarios
  5. 5. Vodafone Proprietary classified as C1 - Public • Wired access • No mobility • Fixed, limited bandwidth • Not secure • Application congestion control • Wireless access • Frequent mobility • Volatile high bandwidth • Security essential • Network resource contention 2010s
  6. 6. Vodafone Proprietary classified as C1 - Public What are the key problems?
  7. 7. Vodafone Proprietary classified as C1 - Public AMPS
  8. 8. Vodafone Proprietary classified as C1 - Public Addressing Mobility/Multihoming Performance Security Interface-centric, not application centric Slow acceleration, Huge headers, End-to-end congestion avoidance, Wasteful retransmission Etc. Mobility signalling storm, Broadcast of new routes None = Expensive/vulnerable overlays; Well-known ports And these are NOT solved by IPv6
  9. 9. Vodafone Proprietary classified as C1 - Public TCP/IP report card  Low application bits per Hz/s  No native mobility/multihoming  No native security  E2E congestion controls Reduced spectral efficiency Mobility overlay required Security overlay required Radio volatility not considered Network issue: Network workaround: ROHC Mobility anchors, IP porting IPsec, DDoS controls Retransmissions, TCP optimisers = costly overheads, reduced performance  No intrinsic QoS/context Best effort delivery DPI/traffic detection
  10. 10. Vodafone Proprietary classified as C1 - Public Hang on… We’ve pretty much coped with this so far…. Hooray! (for Moore’s law)
  11. 11. 11 8K video! A gazillion new connections! Ultra low latency VR services! Frequent mobility/multihoming! Coming to a network near you Timeline 2025-ish
  12. 12. Just increasing capacity does not deliver these goals.
  13. 13. Vodafone Proprietary classified as C1 - Public Number of connections (100x) Data volume (1000x) Data throughput (up to 100x) , Mobility speed (10x), Battery lives (up to ten years) Extreme URLLC requirements!
  14. 14. Vodafone Proprietary classified as C1 - Public • To achieve 5G load scaling, we can throw capacity, NFV, SDN and Network Slicing at the problem.. • This does not solve URLLC – the network protocols themselves need to upgraded IF WE DO NOTHING:
  15. 15. Vodafone Proprietary classified as C1 - Public So in summary: legacy network protocols • …struggle today, and are not fit for tomorrow • …reduce the value of next generation networking • …will not be able to deliver URLLC
  16. 16. Vodafone Proprietary classified as C1 - Public Alternatives are live now
  17. 17. Vodafone Proprietary classified as C1 - Public Next Generation Protocols • Academia, operators, vendors: stimulating the discussion across SDOs • Analysing and testing alternative internetworking protocols • Manageable, discrete steps (no ocean boiling) • Work is public, all feedback welcome! http://www.etsi.org/technologies-clusters/technologies/next-generation-protocols
  18. 18. Vodafone Proprietary classified as C1 - Public Further reading www.pouzinsociety.org www.geddes.com irati.eu Vodafone Quality of bandwidth report 2017
  19. 19. Vodafone Proprietary classified as C1 - Public It’s a wrap kevin.smith@vodafone.com
  20. 20. Vodafone Proprietary classified as C1 - Public The following slides present further details on the AMPS problems introduced by TCP/IP…
  21. 21. Vodafone Proprietary classified as C1 - Public AMPS: ADDRESSING An IP address names the network interface (aka point of attachment)… What should be named: the node that processes the protocol headers What is wrongly named: the network interface 1.2.3.4 5.6.7.8 …which is how you get to the target of the communication – and not the target itself This causes problems…
  22. 22. Vodafone Proprietary classified as C1 - Public AMPS: Mobility & Multihoming This means that to deliver IP packets to the same node over different interfaces requires routing to different addresses… For both multihoming and mobility, the addresses of the interfaces need to change. This means:  IP needs workarounds for mobility and multihoming  Router tables grow rapidly  ‘Layer 2.5’ needed for buffer handovers 1.2.3.4 5.6.7.8 Detach Attach
  23. 23. Vodafone Proprietary classified as C1 - Public Performance: Big headers, Slow Handshakes • Most fields seldom/never change in a flow – but sent in every packet • Big headers = big problem for low- power IoT devices • Header compression considered prohibitively expensive • Connection Synchronisation based on handshakes, not timers • This incurs roundtrips to open and close • Adds unnecessary latency
  24. 24. Vodafone Proprietary classified as C1 - Public Performance: acceleration and capacity usage • Time taken to utilise capacity –adding capacity does not accelerate this! • Means short flows never get up to speed • TCP limits the amount of data that can be in flight – historically set for 64K fixed lines • TCP window scaling workaround has ceiling of 1.07 GB… meaning another workaround likely needed soon.
  25. 25. Vodafone Proprietary classified as C1 - Public Performance: Latency and jitter • Handshakes result in latency e.g. Google/Microsoft experiments on delay impact, est. $75M revenue loss. https://www.thetrainline.com/ reduced the latency of their website by 300ms their revenue increased by £8m/yr. Latency impact on revenue • Jitter as sending rate varies suddenly Jitter impact on customer experience Client-side buffering, VoIP issues, online gaming
  26. 26. Vodafone Proprietary classified as C1 - Public Performance of TCP in the mobile network 26 Noise and retransmissions here reduce throughput, which… …is typically interpreted as congestion by TCP endpoints Either: network proxies TCP to account for these Meanwhile radio retransmissions are not in synch with TCP retransmission 1 2 3 4 Or: TCP wastefully retransmits packets…
  27. 27. Vodafone Proprietary classified as C1 - Public Performance: endpoint congestion controls • Don’t overrun the application – not network! • End-to-end theory: “endpoints should control congestion – and play fair…” • But these are the farthest points from network congestion! Network workaround: TCP optimisers, rate limiters
  28. 28. Vodafone Proprietary classified as C1 - Public Performance: fragmentation, retransmission • IP does not do retransmissions. • TCP will retransmit a fragment – but with a different IP packet ID • = risk of multiple copies of same fragment • MTU discovery patch is a security risk… • No TCP ACK? Does that mean delayed? Or lost? • Retransmission timers don’t account for queuing or changing routes • Head of line blocking RetransmissionFragmentation
  29. 29. Vodafone Proprietary classified as C1 - Public Security: none by default • Minimal/no authentication in routing protocol, congestion control, flow control, ICMP messages, etc. • TCP handshake presents an unnecessary attack vector • Well-known ports mean attackers know where to target • Spoofing due to “Fan-in”: multiple connections to same port means server must rely on values it did not create to distinguish connections • Lack of native IP security means costly overlay of IPsec
  30. 30. Vodafone Proprietary classified as C1 - Public 5G is not one-size fits all • Just increasing capacity is not the answer • Consumer and Enterprise services will require a blend of: Latency, Reliability, Throughput, Pacing, Coverage, Mobility, Durability, Security, Efficiency • …for which the network needs context-aware and performant protocols

×