[Univ of Cambridge][Dept of Engineering]


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D15 Examples Sheet

 

The D15 examples sheet can be found here. It is in Adobe Acrobat format (.pdf)

 

D15 Examples sheet cribs for all questions

 

The D15 examples sheet cribs can be found here. It is in Adobe Acrobat format (.pdf).

 

D15 Phoney Exam Questions and Cribs

 

A phoney exam question from the first half of the course with cribs has been put here. It is in Adobe Acrobat format (.pdf)

 

D15 Coursework

 

To be completed by Friday 30th of November 2001, worth 25% of the course marks.

Part 1. Design a LAN

 

The year is 2001 and you are a wealthy yet cautious industrialist who still has faith in the potential of the telecommunications marketplace. You have recently bought a factory site in the U.K. and you wish to upgrade its computer networks. The facility you have purchased contains the following existing systems, which you would like to remain in place where possible.

 

  1. An assembly plant with semi-automated systems running on an IBM 16Mbit/s standard token ring system. 66 stations on three interconnected rings with token bridges between them. A single station is acting as the token master and is connected to a monitoring system for the assembly plant.
  2. A separate design office, which is 500m from the assembly plant with a road in between which contains, 25 Apple Macintosh CAD workstations, with local printers and a file, email and web server which require 100Mbit/s data rate. There are also 30 high performance PCs which require 1000Mbit/s network connections.
  3. A T2 standard wide area connection is also located outside the design office, which connects to an ATM backbone running TCP/IP.
  4. The head office is based in the USA but would like to be connected to both the design office and the assembly line via a highly secure VLAN structure.

Your task is to design a suitable network structure for this new facility allowing full LAN interconnection between the design office, the assembly line and the head office. In this design please consider the choice of LAN protocols and how they will be interconnected. Please describe potential areas where problems might occur or where careful administration and protocol structure must be focused. You must also produce a rough estimated cost (not including labour) for the equipment needed to build such an interconnected LAN system.

Part 2. Model a LAN

 

Using MATLAB set up a simple model for evaluating IEEE802 CSMA/CD versus IEEE802 token ring protocols, assuming 25 stations and one bridge in the network. All of the traffic will be from the stations to the bridge with no bit errors. Each station will only transmit 1500byte frames, with a 96 bit period interframe gap. CSMA/CD frames will be discarded after 16 deferrals. For each test consider the number or frames lost and the delay incurred by each frame before it is transmitted.

 

  1. 10Mbit/s bit rate, assuming a 45kbyte data file. Each station will use a Poisson statistical distribution for transmission requests for each data file. Model the requests for 20, 50, 75 and 90% probability of a station asking to transmit data.
  2. 10Mbit/s bit rate, assuming a data file of random length between 1500bytes and 1.5Mbytes long. Each station will use a Poisson statistical distribution for transmission requests for each data file. Model the requests for 20, 50, 75 and 90% probability of a station asking to transmit data.
  3. 100Mbit/s bit rate, assuming a 45kbyte data file. Each station will use a Poisson statistical distribution for transmission requests for each data file. Model the requests for 20, 50, 75 and 90% probability of a station asking to transmit data.
  4. 100Mbit/s bit rate, assuming a data file of random length between 1500bytes and 1.5Mbytes long. Each station will use a Poisson statistical distribution for transmission requests for each data file. Model the requests for 20, 50, 75 and 90% probability of a station asking to transmit data.

 

Sample m-files for generating Poisson statistics include poissrnd.m and poisspdf.m

More advanced features can also be incorporated, including bursty traffic models, real Internet traffic models taken from monitoring sites.

 

A short report should include the conclusions of these modelling conditions as well as a description of how your model works and a code listing.

 

 


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Last content change : July 01