Principles of Communications, Digital Communication II Past Paper
Readings,
- Textbook: An Engineering Approach to Computer Networking: ATM Networks, the Internet, and the Telephone Network, by S. Keshav, 1997, Addison-Wesley.
- Useful chapters: Ch 5 layering, Ch6 System Design, Ch 9 Scheduling, Ch 11 Routing, Ch 13 Flow control, Ch 14 Traffic management [One-to-one mapping with Lecture slides].
- Fibbing paper, Optimization paper.
- Data center, QJump paper.
Routing
DV vs LS
General
Inter-domain
Intra-domain
Fibbing
Multi-protocol label switching
Segment
Multicast
Mobile and telephone
Mobile
Telephone circuits: dynamic alternative routing
Flow / congestion control
Scheduling
FIFO, Priority Queueing
Generalized Processor Sharing (GPS): "bitwise round-robin" benchmark.
Weighted Round Robin (WRR), Weighted Fair Queuing (WFQ), Deficit Round Robin (DRR)
Fairness
Queue management: drop from T/H; smart/random drop; flush
Data centers
QJump, a switch priority queueing, combined with end systems traffic regulation, by exploiting its regular topology & traffic matrix (src-dst) & source behaviour.
Optimization
Traffic management
QoS + Connectivity.
Traffic classes and synchrony
- Guaranteed Service / Inelastic (delay sensitive and unusable for low bandwidth, i.e. utility is 0)
- Synchronous / real-time, e.g. gaming, video conferencing.
- open-loop flow control with admission control (RTP over UDP).
- Best Effort / Elastic (benefit from throughput, but not delay-sensitive)
- Asynchronous / non-real-time, e.g. file transfer, email, web browsing.
- closed-loop flow control with congestion control (TCP), with rate adaptive to network conditions.
Utility function, Traffic model (measure or math), time scale, renegotiation, admission control, peak load pricing, capacity planning and macroscopic QoS.
Related: multicast (RSVP : Resource reSerVation Protocol)
System design
Layering