7-11.6.08 @Snagstuhl

Undiscombobulating Un-Flows.

Jon Crowcroft, University of Cambridge

Currently IMDEA Networks.Jon.Crowcroft@cl.cam.ac.uk

http://www.cl.cam.ac.uk/~jac22

Cdn v. swarm – matrix?

What’s a Flow?

The idea of flow is being undone We’re splitting flows over multipath We’re sourcing traffic in swarms At a point in the net, how do you tell?

Guilt by association used to be possible C.f. ASM – Any Source Multicast Flow ID was group address + Dst Port Need to recover this identity Eg. so net (re-)feedback works Need to work out what appropriate rate is.

Data Driven Demands

Next step in evolution of CDN Is to make the swarm a building block Still have higher level identifiers Meta-data, pub/sub/interest etc But no lower level id

Does statistical mux/drop in queue + Rate adjustment at edge Still add up to a sensible behaviour?

And what is the rate adjustment Given there’s more than one edge?

Lets dream we had ASM still

Could assign marks to a swarm Based on group Each receiver could assign weight to feedback And each source could adjust aggregate rate to

group to meet fair/efficient goal Question 1: Does this new “flow unit” still

aggregate the right way? Question 2: does it still improve over

multipath Question 3: mech. Do mechanisms to

assign flows to multipath subpaths still apply to this new type of flow unit

Some more small nits

How to do reliability (recall srm) We do now have fec and netcoding

as first class building blocks…so maybe ok

But in the presence of packet drop as a CC feedback signal…

…fec level to add isn’t totally obvious

Questions?

Just to make matters worse, All the flows are short lived.