computer networking and management

COMPUTER NETWORKING & MANAGement Task 1 – 15 Marks Table 1 below, gives the round-trip time (RTT) for 30 individual segments sent over a TCP connection: Segment 1 2 3 4 5 6 7 8 9 10 RTT (ms) 130 138 122 124 131 139 139 121 134 127 Segment 11 12 13 14 15 16 17 18 19 20 RTT (ms) 267 139 126 134 141 137 291 123 134 139 Segment 21 22 23 24 25 26 27 28 29 30 RTT (ms) 141 142 139 122 123 143 215 134 122 134 Table 1 a) For each segment, making any necessary assumptions, calculate the following and plot the data on a graph: • The exponentially weighted moving average (EWMA) of RTT (sometimes referred to as Estimated RTT). • The variability of RTT (sometimes referred to as DevRTT). • An appropriate timeout internal for use when transmitting the next TCP segment. b) For the connection data given in Table 1, using your assumptions, determine if premature timeout will occur for any of the segments. If so, which? Task 2 – 5 Marks A small office / home office (SOHO) LAN has six workstations, connected together via Ethernet. This small network is connected to the Internet via a network address translation (NAT) enabled router. • Explain the operation of the NAT enabled router and critically appraise this arrangement. • Explain how the workstations may obtain their IP addresses. • Explain how the router may obtain the IP address for its Internet interface. Computer Networking & Management September 2009 Final ©NCC Education 2009  Task 3 – 10 Marks a) Discuss the following terms as applied to the HTTP and explain how each can provide performance improvements to HTTP applications: • Persistent connections • Pipelining • Conditional GET / client caching b) Outline THREE different Internet protocols commonly used to retrieve mail from mail servers by e-mail user agents. Compare and contrast these. Task 4 – 10 Marks a) Explain how the Integrated Services (Intserv) architecture allows an Internet connection to have a guaranteed Quality of Services (QoS). b) Explain how the Differentiated Services (Diffserv) architecture allows an Internet connection to have a differentiated QoS. c) Explain why it is likely to be difficult to implement Intserv in the core of the Internet. Task 5 – 60 Marks Using available Internet and library resources, research the provisions of the ISO standard 17799: 2005 – code of Practice for Information Security Management. a) Outline the eleven Security CLAUSES and CONTROL OBJECTIVES of the standard in an appropriate format. (Approximately 1000 and 1500 words respectively - overall total 2500 words). b) For each of the clauses, critically appraise how the main control objectives relate to an organisation with which you are familiar. Also, briefly outline what would be required to enable the organisation to meet the objectives. (Approximately 2000 words). NOTE: Just copying information from websites without individual interpretation or comments is discouraged and will not gain marks. Also, see notes on plagiarism on the front cover of this assignment.  Submission Requirements • A single word processed document containing all reports and other documentation i.e. explanations, output reports and page images of graphic tools etc. pertaining to all tasks. • Maximum word limit is 7000 words (+/- 10%) not including the appendices. • The document should be properly structured with a table of contents, bibliography (online and literature sources) and appendices (where necessary). Refer to the Assignment Presentation Requirements on Campus for more information. (See front cover). • Produce clear and specific reasoning and argument to justify answers. • Include screen dumps for all your practical work. •