1. 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

2. Pros and Cons of IPv6 as it is now Ipng requirements capture was comprehensive But decision was marred 1. Famous false start:ISOCLNP==DECNET 2. S(simple|steve)IP == XNS 3. P(paul)IP == MPLS + Nimrod Committee Compromise Does mobile Doesn’t do multihoming

3. 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?

4. 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

5. 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

6. 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?

7. 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/

8. 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)

9. 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

10. Underlays more revolutionary than overlays Not many examples - MPLS, gMPLS Finesse management/routing problem 3gpp/cellular Finesse mobility&billing problem Other?

11. 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?

12. 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?

13. 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!