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Hot Topics in Networking

Hot Topics in Networking. Stefan Savage Department of Computer Science and Engineering University of Washington, Seattle. Overview. Some hot topics Multimedia support (diffserv vs intserv) Multicast Unified congestion control Network measurement & analysis Classificiation

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Hot Topics in Networking

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  1. Hot Topics in Networking Stefan Savage Department of Computer Science and Engineering University of Washington, Seattle

  2. Overview • Some hot topics • Multimedia support (diffserv vs intserv) • Multicast • Unified congestion control • Network measurement & analysis • Classificiation • Commercial drivers for the next 5 years • What goes on here? • Hot Networking Schools

  3. Multimedia support • How to make audio, video, data coexist? • Integrated Services (IntServ) (Zhang@UCLA) • Guaranteed service • Reserve necessary resources - global • RSVP, controlled by end-user • Differentiated Services (DiffServ) (Clark@MIT) • No guarantee • Best-effort prioritization – per hop • Controlled by administrator (measure traffic at edge and mark packets with appropriate “label”

  4. Multimedia support (2) • Diffserv won (Intserv dead/dying in wide area) • Cheap to implement & scalable (< per-flow state) • Doesn’t require global consensus/settlement • Really cool work from Ion Stoica @CMU • Dynamic Packet State (DPS) • Instead of having routers maintain per-flow state, carry it in packet label • By careful treatment of labels at network border can approximate global behaviors with distributed local operations

  5. Multicast • IP Multicast is a many-to-many publish/subscribe mechanism • Has been the hammer for many problems in the last 6 years: • SRM: reliable one-to-many communication, • RLM: layered one-to-many video transmission, • MINC: distributed network measurement, etc. • And the source of many problems: • How to do routing? • How to make it secure? • How to implement efficiently?

  6. Multicast(2) • Contraversial emerging consensus • IP Multicast is doomed in the wide-area • Will be sporadically available in local area • Why? • Administrative challenges • How to route?, how to control?, how to charge? • Technical challenges • Pure one-to-many schemes (e.g. Stanford’s EXPRESS) • Commercial challenges • “Application-level” multicast: Real Broadcast Network, etc… work well

  7. Unified congestion control • Congestion control (how to share the network) • Well studied for TCP • What about UDP traffic (e.g. RealAudio) and Multicast? • How can we make them all co-exist fairly? • TCP-friendly multimedia protocols (ISI/USC) • Equation-based congestion control (ACIRI) • Congestion Manager (MIT)

  8. Measurement & Analysis • The Internet is supremely hard to measure • VERY heterogeneous • VERY large • Heisenberg effects • Still… lots of efforts to measure and understand traffic dynamics, routing, use characteristics, etc…

  9. Measurement & analysis (2) • Almost any distribution of interest has a heavy tail… • Leads to fractal arrival pattern • Wavelet-based analysis: very hot (AT&T) • Turn to modeling • TCP models (Umass, ACIRI, PSC, UW…)

  10. Some random results • Web • Web page popularity is Zipf (Xerox, BU) • Benefit of caches limited (20-45%) (UW) • Packet interarrival • Not poisson, multifractal – different parameters at different time scales (AT&T) • Network paths • Asymmetric routes, loss, delay (Berkeley, UW) • Routing • Not stable, both because of bugs, and algorithm issues (Umich, Berkeley, Microsoft) • Not even vaguely optimal (UW)

  11. Classification • Issue: how to determine if packet has property X as fast as possible • Originally for doing lookups in routing table, now also for firewalls, NAT’s, etc… • Movement to deal with more and more complicated properties • Range matches, range matches with predicates, etc… • A few schools (e.g. Washington U) dominate

  12. Commercial drivers • Bandwidth • Wide-area: Fiber (2.4-10Gbps), LVLT, Q • Last-mile: DSL, Cable, Radio, 1-10Mbps • E-commerce • Reliability, security • Wide-area content distribution systems • Akamai, Real Broadcast Network

  13. Commercial drivers (2) • Voice/Data Integration • Border services • Web cache, NAT, Firewall, IDS, Transcoder, etc.. • Cost recovery • Settlement, preferred services, directed advertising, content-provider benefit model

  14. Hot networking schools • Berkeley: Katz, McCanne, Brewer • CMU: Hzang, Steekiste, Fisher • MIT: Morris, Balakrishnan, Clark • Stanford: Cheriton, McKeown, Baker • Michican: Shin, Jahanian, Jamin • Umass: Kurose, Towsley • Washington U:Parulkar,Schmidt,Turner,Varghese • USC: Estrin • Labs: ACIRI, AT&T, WRL (Mogul)

  15. What’s my deal? • Networking in uncooperative environments (e.g. the Internet) • Particular foci • Network measurement • Routing, Path tools (sting), Web latency • Protocol robustness • Misbehaving TCP’s, IP Traceback

  16. What’s going on here? • Tom Anderson: • Detour project: application level unicast routing • Lots of TCP congestion control work • Network measurement • Robustness (bad TCP’s & IP Traceback) • David Wetherall • Active Networks, compression, robustness stuff • Hank Levy • Web tracing, sharing among clients, limits of Web caches, tracing of multimedia traffic

  17. Some outside systems/networking candidates

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