Computer Networks - Network and Communications - Exam, Exams of Data Communication Systems and Computer Networks

Download Computer Networks - Network and Communications - Exam and more Exams Data Communication Systems and Computer Networks in PDF only on Docsity! Ollscoil na hÉireann, Gaillimh GX_____ National University of Ireland, Galway Semester II Examinations, 2007/2008 Exam Code(s) 2BF1 Exam(s) 2nd Business Information Systems Module Code(s) MS211 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? (18 Marks)