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Network Architecture (R02) #2 Evolution v. Revolution. Jon Crowcroft, http://www.cl.cam.ac.uk/~jac22 http://www.cl.cam.ac.uk/teaching/1011/R02. Pros and Cons of IPv6 as it is now. Ipng requirements capture was comprehensive But decision was marred Famous false start:ISOCLNP==DECNET
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Network Architecture (R02) #2Evolution v. Revolution Jon Crowcroft, http://www.cl.cam.ac.uk/~jac22 http://www.cl.cam.ac.uk/teaching/1011/R02
Pros and Cons of IPv6 as it is now • Ipng requirements capture was comprehensive • But decision was marred • Famous false start:ISOCLNP==DECNET • S(simple|steve)IP == XNS • P(paul)IP == MPLS + Nimrod • Committee Compromise • Does mobile • Doesn’t do multihoming
Some other IPv6 plus points • Large addr space - • Internet of things (foreseen) • can hash into with low collision probability • Provider, geographic, topological • EID/Routing Hint separation (8+8) • Transport changes…. • TCP socket = 5 tuple • Other transport use flow label?
Other IPv6 tricks • Could do zeroconf • Can use Host Id Protocol • or other crypto-assigned address mech, • Can in principle use flow label • Can use hop&end options without so much impact on router fast path v. slow path for IPv4 Options • including overloaded Router alert
Evolution v. Revolution • http://www.cl.cam.ac.uk/teaching/1011/R02/papers/p36-rexford.pdf • Is a local cached copy of counterpoint between J Rexford (Princeton) and C Dovrolis (Gatech) on evolution v. revolution • Prompted by discussion in GENI and other programms • Clean Slate v. Incremental
Clean Slate • Throw out preconceptions/assumptions • Design new net • Then figure out how to deploy • Try and repeat 1973-1988 somehow • Useful at least in some Zen-like sense • What would you build for future with nanotechnology, 3D printers, quantum information processing etc?
Incremental • Sometimes term “incremental” used “negatively” • Reality is its useful • Eg. Resource Pooling and Multipath IP and Multipath TCP • See http://nrg.cs.ucl.ac.uk/mptcp/
Overlays and Underlays • IP was once an overlay • On x.25 and on PSTN • Then moved down to bare metal • ip on photons too • Overlays are a deployment/evolutionary route • see national academy of science on “looking over the fence at network research)
Other overlay schemes • Mbone, 6bone, abone • RON • Application Layer Multicast • IP on SMS and on Fb! • IP on DNS • Typically tunnel…but • IP in IP overhead • IP on VC - complexity • Circuit setup/teardown • #circuits, qos • routing
Underlays • more revolutionary than overlays • Not many examples - • MPLS, gMPLS • Finesse management/routing problem • 3gpp/cellular • Finesse mobility&billing problem • Other?
Deployment of new transport • How can it be hard? • Because of firewalls & IDS and DPI • And packet normalisers • Default is “unknown” == “bad” • Some benefits of Multipath TCP • Resource pooling for multihomed server • Resilience to handover for multihomed mobile • Data center - removes hotspots in interconnect • Downside - general case needs multipath IP • Path selection from non multihomed end point?
Next talk for 19/10/10 • What was really wrong with original (Any Source) Multicast • How has one-to-many other ways - CDN - been so succesful even though it makes no efficiency sense?
First Essay (due Oct 29) • Take one of • LIRA/NIRA, I3, IPNL • Compare with baseline (IPv4/v6) • Evolution v. Revolution (see paper from CACM on course web page) • What do they add to the mix • E.g. scale, multihome, multicast, mobile • E.g. security (what threats), performance • Where do they fall down • 2-4 pages of notes • Remember to cite any sources you use!