1 LAB 1 T A Maram Al Muhareb

1 LAB 1 T. A. Maram Al. Muhareb NET 221 D : COMPUTER NETWORKS FUNDAMENTALS

Question 1 3 1. Summarize Computer networks uses. Computer networks / Andrew S. Tanenbaum-- 5 th ed

Sol. 1 4 Networks have many uses, both for companies and for individuals, in the home and while on the move. Companies use networks of computers to share corporate information, typically using the client-server model with employee desktops acting as clients accessing powerful servers in the machine room. For individuals, networks offer access to a variety of information and entertainment resources, as well as a way to buy and sell products and services Behrouz A. Forouzan” Data communications and Networking

Q 2 5 What are the two types of the line configuration? Behrouz A. Forouzan” Data communications and Networking

Sol. 2 6 (or types of connections) Point- to - point and multi points Behrouz A. Forouzan” Data communications and Networking

Q 3 7 You have two computers connected by an Ethernet hub at home. Is this a LAN, a MAN, or a WAN? Explain the reason. Behrouz A. Forouzan” Data communications and Networking

Sol 3 8 This is a LAN (Local Area Network). LANs typical cover a building and operate at high speeds. MAN usually covers a city. WANs may cover a country or a continent. Behrouz A. Forouzan” Data communications and Networking

Q 4 9 Why are protocols needed in a network? Behrouz A. Forouzan” Data communications and Networking

Sol 4 10 A protocol defines what is communicated, in what way and when. This provides accurate and timely transfer of information between different devices on a network. It allow communication to be understood. Behrouz A. Forouzan” Data communications and Networking

Q 5 11 For n devices in a network, what is the number of cable links required for: A mesh , ring, bus, and star topology. Behrouz A. Forouzan” Data communications and Networking

Sol. 5 12 Mesh: n (n – 1) / 2 b. Star: n c. Ring: n d. Bus: one backbone and n drop lines Behrouz A. Forouzan” Data communications and Networking

Q 6 13 Draw a hybrid topology with a ring backbone and two bus networks. Behrouz A. Forouzan” Data communications and Networking

Sol. 6 14 Need two repeaters connecting to the Ring. Connect these repeaters to the buses. Behrouz A. Forouzan” Data communications and Networking

Q 7 15 For each of the following four networks, draw the topology then discuss the consequences if a connection fails. a. Five devices arranged in a mesh topology Behrouz A. Forouzan” Data communications and Networking

Sol 7. a 16 a. Mesh topology: If one connection fails, the other connections will still be working.

Q 7. B 17 b. Five devices arranged in a star topology (not counting the hub) Behrouz A. Forouzan” Data communications and Networking

Sol 7. b 18 b. Star topology: The other devices will still be able to send data through the hub; there will be no access to the device which has the failed connection to the hub. What will happen if the hub fails ?

Q 7. C 19 c. Five devices arranged in a bus topology Behrouz A. Forouzan” Data communications and Networking

Sol 7. C 20 Bus Topology: All transmission stops if the failure is in the bus. If the drop-line or a device fails, only the corresponding device cannot operate.

Q 7. D 21 d. Five devices arranged in a ring topology Behrouz A. Forouzan” Data communications and Networking

Sol 7. D 22 Ring Topology: The failed connection may disable the whole network unless it is a dual ring or there is a by-pass mechanism.

Q 8 23 Assume six devices are arranged in a mesh topology. A. How many cables are needed? B. How many ports are needed for each device? Behrouz A. Forouzan” Data communications and Networking

Sol 8 24 Fully connected mesh network has n(n-1)/2 physical connection to link n devices. n= 6 >> 6(6 -1)/2 >> 6*(5)/2=30/2=15 cables B. Every device on the network must have n-1 input/output (I/O) ports. A. n= 6 >> 6 -1 = 5 ports Behrouz A. Forouzan” Data communications and Networking

Q 9 25 Compare between the different types of network according to their applications , range, and topology Behrouz A. Forouzan” Data communications and Networking

Sol 9 26 Behrouz A. Forouzan” Data communications and Networking

27 Behrouz A. Forouzan” Data communications and Networking