Principles of Communications Week 8 to Nov 23rd/L15

 This week is two Big Pictures 

On Nov 21, we do:

1/ Traffic Management over multiple time scales - linking together several ideas between routing/congestion control, open and closed loop flow control, admission, pricing, and, finally, a bit about signaling.

feedback/admission work at any time scale

short> reduce rate/ lose packets

medium> try again later

long>change to a better provider

So note peak rate pricing is just a slow version of congestion control + shadow prices.

Note using a single network may amortize costs well, but a single technology has single failure mode - the model of copper/fiber/radio has a lot of fault tolerance, which is high value for critical infrastructure.

Note that the problem with capacity planning and traffic matrix/source behaviour in the general internet is that a) it isnt a regular topology, b) each ISP is doing it in competition but also in cooperation with other ISPs! However, this paper showed how well the ISPs coped when everyone switched to working/learning from him the internet in the age of covid

On Nov 23rd we'll cover:

2/ System Design Rules - these are rules of thumb that apply in many systems, processsor design, operating systems, networks, etc etc

More can and will be said...