Digital Communications II
Principal lecturer: Prof Ian Leslie (email@example.com)
Taken by: Part II
Lecturer: Professor I.M. Leslie and others (firstname.lastname@example.org)
No. of lectures: 12
Prerequisite course: Digital Communication I
This course is a prerequisite for
Security (Part II).
This course aims to provide a detailed understanding of how (wide
area) computer networks operate, and to present the issues which are
involved in building such systems. It also hopes to cover a selection
of topics which relate to recent trends in digital communications
- Review of basic principles.
Abstraction, layering. Concept of channel. OSI reference model.
- TCP/IP Details and Gore.
IP stack. Concurrency and buffering in BSD. Socket
implementation. IP addresses and routing.
IP Checksum. Datagrams: IP fragments, UDP/IP, NFS. TCP: states,
coding, MSS, ACKs, retransmission. Congestion control. More TCP.
Routing: CIDR, ASes, EGP/IGP. Distance vector schemes (e.g. RIP).
Link state schemes (e.g OSPF). IP Multicast.
- Quality of service and ATM.
Guarantees versus best effort.
Architecture, motivation. Relation to packet switching, circuit
switching. Quality of service considerations. Resource management.
Performance quantities. VR performance, effective bandwidth. ABR
- Transmission and Technology.
Access networks: xDSL, Cable modems, LMDS, satellites, etc. Wide
area networks: fibre, DWDM, IP over ATM/Sonet/"fibre". System area
- QoS in the Internet.
Guarantees versus best effort. Flow specs. IntServ and
DiffServ. RSVP. Economic models.
- Additional Topics.
At the end of the course students should be able to
- enumerate and explain the layers of the OSI reference model
- define effective bandwidth
- describe how TCP attempts to handle congestion in the
- compare and contrast connectionless and connection-oriented
- explain how IP routing works
- argue for or against the provision of Quality of Service
(QoS) in the Internet
- understand the motivation behind and operation of
admission control algorithms
- give a basic explanation of how the TCP protocol works
- differentiate between the IntServ and DiffServ approaches
- realise the O/S issues in supporting TCP urgent data
- compare and contrast switching and routing
Comer, D. & Stevens, D. (1995). Internetworking with TCP-IP,
vol. 1 and 2. Prentice-Hall (3rd ed.).
Halsall, F. (1992). Data Communications, Computer Networks and Open
Systems. Addison-Wesley (3rd ed.).
Schwartz, M. (1987). Telecommunication Networks: Protocols, Modeling
and Analysis. Addison-Wesley.
past exam questions are also on line.
Updated Mon Nov 8 16:13:56 GMT 1999