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Ollscoil na hÉireann, Gaillimh GX_____
National University of Ireland, Galway
Semester II Examinations, 2007/
Exam Code(s) 2BF
Exam(s) 2 nd^ Business Information Systems
Module Code(s) MS
Module(s) Networks & Communications I
Paper No. 1 Repeat Paper Special Paper
External Examiner(s) Professor Hans van der Heijden Internal Examiner(s) Professor J. F. Collins Dr. A. Nachev
Instructions: Answer three questions. All questions carry equal marks.
Duration 2 hrs No. of Answer books
Requirements : Handout MCQ Statistical Tables Graph Paper Log Graph Paper Other Material
No. of Pages Department(s)
SECOND YEAR BUSINESS INFORMATION SYSTEMS
(MS211) NETWORKS AND COMMUNICATIONS I
Time Allowed: TWO hours
Answer THREE questions. All questions carry equal marks.
Q1.
(a) With respect to computer networks , briefly distinguish between each of the following pairs of terms:
i) Amplitude modulation (AM) vs. frequency modulation (FM). ii) Point-to-point vs. multi-point line configuration. iii) Network standard vs. network protocol. iv) Multimode step-index vs. multimode graded-index optical fibers. v) Error-correcting vs. error-detecting codes. (15 Marks)
(b) A data unit is encoded by a sender using Hamming error-correcting code. The receiver receives 101010010010 , which contains the original data unit and redundancy.
Given your knowledge of the Hamming code, answer the following questions and give brief explanations. Assume that only a single-bit error is possible.
i) Is this data transmission error-free? If not, fix the error. ii) What is the original data unit?
Q4.
(a) A packet-switched network is one way for companies to create a wide area network (WAN) link without the per-mile cost of a dedicated leased line. In general, packet-switched services fall into one of three categories: X.25, Frame Relay, and ATM.
Distinguish between the three types of services.
(13 Marks)
(b) Wireless communication has become a ubiquitous part of modern life, from global cellular telephone systems to local and even personal - area networks. With respect to wireless communications describe the structure and functioning of each of the following:
i) Satellite navigation systems. ii) Satellite phones. iii) Radio Frequency (FR) LANs (IEEE 802.11x)
(20 Marks)
Q5. (a) With respect to the client-server paradigm answer the following questions:
i) What is the difference between a client and a server? ii) What is middleware? iii) What is the difference between an active open and a passive open? iv) How does a server that handles clients iteratively differ from a server that handles clients concurrently? v) What is the difference between two-tier architecture, three-tier architecture, and N-tier architecture? (23 Marks)
(b) When LANs really start to grow, network data traffic can begin to overwhelm the available bandwidth on network media. A bridge is a networking device used to help conserve the bandwidth available on the network and to improve the network performance.
Discuss the above statement.
