Digital Communications II

Digital Communication II

Lecturers: Ian Pratt, Jon Crowcroft
(ian.pratt@cl.cam.ac.uk, jon.crowcroft@cl.cam.ac.uk)

No. of lectures : 16

Prerequisite course: Digital Communication I

This course is a prerequisite for Security (Part II).

Aims

This course aims to provide a detailed understanding of how computer networks operate, through the examples of the Internet, and presents ways to build such systems. It also covers a selection of topics which relate to recent trends in digital communications systems. The material falls roughly into two halves: Protocols, and Technologies.

Lectures

• Introduction. Course overview. Abstraction, layering. The OSI reference model. IAP/JAC

• The Internet: IP. IP overview/review. Networking in Unix: structures, buffering, sockets, network interfaces. IP addresses and (simple) routing. Subnetting. IP checksum. Fragmentation. JAC

• The Internet: routing. ROADS and CIDR. Terminology: AS, IGP, EGP. Routing protocols: distance vector versus link state. Examples: RIP, OSPF. AS routing: I-BGP/E-BGP, metrics. JAC

• The Internet: IPv6. Concepts. Internet multicast model. Applications. Basic implementation. Refinements. Congestion control. RJB

• The Internet: network resource management. Differentiated and Integrated Services. Signaling (RSVP) and Admission Control, Forwarding and Scheduling, Policing and Shaping. The future. JAC

• The Internet: multicast and QoS routing. Other TCP details. Internet multicast model. Applications. Basic implementation. Refinements. JAC

• The Internet: UDP, TCP TCP operation, state transitions. Handling loss: acks and retransmissions. Estimating RTT. Basic congestion control. Improving things: TCP vegas, SACKs, ECN. [JAC, 2 lectures]

• The Internet: Applications, Multimedia, NFS & HTTP RTP operation, Playout adaption; RPC & Network File Systems; HTTP, HTTP 1.1 - making it all work JAC

• ATM case study Multiplexing and virtual circuits. Signalling. ATM Adaption Layers. Quality of Service CBR, VBR, ABR. IAP

• Wide Area Networks. Fibre Technology. Long-haul link design. Dense Wave Division Multiplexing. Sonet/SDH. MPLS. Packet over SONET. Optical switching. IAP

• Access Networks. Cable Modems. xDSL. Fixed wireless. Satellite. Firewalls and Network Address Translation. IAP

• Local Area Networks and System Area Networks. Fast/Gigabit Ethernet. Optimising latency. Host interface design. User-space protocol processing. IAP

• Congestion Pricing. Model and motivation. Practical considerations. The future. DRM

• Additional Topics. To be announced. IAP+

Objectives

At the end of the course students should be able to

• enumerate and explain the layers of the OSI reference model

• compare and contrast connectionless and connection-oriented networks

• explain how IP routing works

• describe the components of the Internet resource management system

• describe how and why TCP attempts to handle congestion in the network

Recommended books

Srinivsan Keshav. (1997). An Engineering Approach to Computer Networking. Addison-Wesley Pub Co; (1st ed.); ISBN: 0201634422

Alternative to Keshav: Bruce S. Davie & Larry L. Peterson & David Clark (1999). Computer Networks: A Systems Approach. Morgan Kaufmann Publishers (2nd ed.); ISBN: 1558605142

W. Richard Stevenes (1994) TCP/IP Illustrated, Volume 1: The Protocols. Addison-Wesley Pub Co, (1st ed.); ISBN: 0201633469

Alternative to Stevens: Douglas Comer (2000). Internetworking with TCP/IP Vol. I: Principles, Protocols, and Architecture Prentice Hall (4th ed.); ISBN: 0130183806

Backround: Balachander Krishnamurthy & Jennifer Rexford (2001) Web Protocols and Practice: HTTP/1.1, Networking Protocols, Caching, and Traffic Measurement. Addison-Wesley Pub Co (1st ed.); ISBN: 0201710889

Notes

• OSI Model and layering (.ps.gz)
• TCP/IP section (.ps.gz)
• IPv6 (.pdf) (Copyright Richard Black)
• Routeing and Multicast (.ps.gz)
• Scheduling and Queue Management (.ps.gz)
• Integrated Services (.ps.gz)
• QoS APIs (.ps.gz)
• ATM (.ps.gz)
• Wide Area Networks (.pdf)
• Access Networks (.pdf)

Useful Links

• IETF Home Page
• RFCs etc
• IP Hacks & Attacks
• TCP/IP FAQ
• ADSL CAP vs DMT article
• ADSL article
• Cisco DWDM article
• Excellent presentation on router design

The past exam questions are also on-line.