MBA 1st Year Network And Internet Long Questions Answers Study Notes
Q.3. Describe about LAN connectivity devices.
Or What are the various devices which operate in WAN? Explain their utility also. (2012-13)
Ans. LAN Connectivity Devices: LAN connectivity devices are described below:
1. Repeater: Boost signal in order to allow a signal to travel further and prevent attenuation. Attenuation is the degradation of a signal as it travels further from its origination. Repeaters do not filter packets and will forward broadcasts. Both segments must use the same access method, meaning that you can’t connect a token ring segment to an Ethernet segment. Repeaters will connect different cable types.
2. Bridge: The functions of a bridge are same as a repeater, but it can also divide a network in order to reduce traffic problems. A bridge can also connect unlike network segments (i.e. token ring and Ethernet). Bridges create routing tables based on the source address. If the bridge can’t find the source address, it will forward the packets to all segments.
3. Router: A router will do everything that a bridge will do and more. Routers are used in complex networks because they do not pass broadcast traffic. A router will determine the most efficient path for a packet to take and send packets failed segments. Unroutable protocols can’t be forwarded.
4. Brouter: A brouter has the best features of both routers and bridges in that it can be configured to pass the unroutable protocols by imitating a bridge, while not passing broadcast storms by acting as a router for other protocols.
5. Gateway: Often used as a connection to a mainframe or the Internet, gateways enable communications between different protocols, data types and environment. This is achieved via protocol conversion, whereby the gateway strips the protocol stock off the packet and adds the appropriate stock for the otherside.
Devices Opearating in WAN
Various devices which operate in WAN are:
1. Router: It prevent the flow of broadcast traffic from one LAN to another. They can support any desired protocol or the network topology.
2. Gateways: It can be implemented completely in software, in hardware or as a combination of both. They basically translate the protocols to allow terminals on two dissimilar networks to communicate.
3. Modem: It stands for modulator-demodulator. The process of converting a digital signal to an log signal is called modulation while demodulation is the process of reconverting the analog signal back to a digital signal. It is useful in connecting LAN with the Internet. It has high speed and is the most widely used data communication.
Q.4. Computers at multiple locations are supposed to share data, what can be different topologies for networking system? Explain.(2015-16)
Or Explain the concept of topologies,(2013-14)
Or Explain tree, bus and star topology with the help of examples.(2012-13)
Or Describe ring topology and its characteristics.
Or What Is network topology? What are its different types? Explain.(2014-15)
Ans. Topology: The topology is defined as a geographical arrangement on
defined as a geographical arrangement of computer network Javices. It is the way through which the end points of the terminals or stations are linked together. The various types of network topologies are:
1. Bus Topology: It is a type of physical network in which a single coaxial link the devices present in the network, Bus topology requires less amount of cabling and is least expensive. It is the simplest topology amongst all others. A device which is to communicate with other sends a message which is seen by other device in the network but only the recipient which is intended to receive it accepts that message.
2. Ring Topology (Each computer is connected to the next in a ring with no end to the network): Each device is connected to the ring by an access connector, which is connected to a repeater that is actually on the
Ring. Typically, transmission media are coaxial cable, fibre optic or twisted pair: A signal is passed along the ring in
l one direction from device to device, until it reaches its destination. When a device receives a signal intended for another device, its repeater generates the bits and passes them along the media.
A ring is relatively easy to install and reconfigure. Each device is linked only to its immediate neighbours (either physically or logically). To add or delete a device requires moving only two connections. Fault isolation is simplified. Generally, in a ring, a signal is circulating at all times. If one device does not receive a signal within a specified period, it can issue an alarm. The alarm alerts the network operator to the problem and its location.
(a) Line Speed: Channels can be classified as low, medium or high speed. Low speed channels, which were originally developed for use of teletypes, operate at a speed of upto 1200 bits per second (bps). Medium or voice-grade lines carry transmissions of 2400 to 9600 bps. The carrying capacity in the upper range of a voice-grade line can be attained only by conditioning or electronically balancing the line. High speed lines operate at speeds of upto 1.544 million bits per second (Mbps) or more.
(b) Switched/Non-switched Line: A dial-up or public line is known as switched line. These lines use the public telephone network. They are available as long as the connection is made and their cost varies according to mileage, time of the day and duration of the connection. They are not very reliable as the connection may break several times due to the noise and various other interferences. You have to dial again and again to reconnect.
Non-switched lines are also known as leased, dedicated or private lines. These lines are dedicatedly connected between two computers. There is no need to dial in order to make connection. These are very reliable but they cost very high.
(c) Mode: Depending on the terminal equipment and the application, communication channels can be arranged for operation in one or more of three basic transmission modes:
(i) Simplex Transmission Mode: Simplex transmission is one directional only. Suppose there are two terminals A and B. Transmission is possible from A to B
For example, a terminal at a remote location may be used only for entering and reporting data on climate conditions, inventory levels or order status to a centralised processor,
(ii) Half-duplex Transmission Mode: Halfduplex allows transmission in both the Direction of data at time 1 directions but not at the same time. So for two terminals A and B, transmission is possible from A to B and from B to A but not simultaneously.
(iii) Full-duplex Transmission Mode: With full-duplex mode, transmission can be made in both directions at the same time. It gives the unidirectional traffic which may be a disadvantage of a ring topology. In a simple ring, a break in the ring (such as a disabled station) can disable the entire network. Using a dual ring or a switch capable of closing off the break, can solve this weakness.
3. Star Topology: A star topology network ties user computers to a central computer via hub. This topology does not allow direct traffic between devices. If one device wants to send data to another, it sends the data to the hub which then relays the data to the other connected devices.
It is very robust. If one link fails only that link is affected. All other links remain active. This factor also tends itself to easy fault identification and fault isolation.
In this topology, more cabling is required than bus or ring topology. It is more expensive than the previous two.
4. Mesh Topology: Refer to Section-B, Q.3.
5. Tree Topology: It is a network topology containing zero or
nodes which are linked together in a hierarchical manner here the topmost node is termed as roots and have zero or more child nodes connected to each other by edges. Nodes sharing the
terminals me parents are called siblings. Every node in a tree has exactly menarent node and all nodes in the tree are descendants of the root node.
All these relationships ensure that there is always one path from one node to the other node in the tree topology.
Q.5. What is newsgroup? Explain the ways of accessing information over the internet.
Or What is a gopher?(2006-07)
Ans. Newsgroup: Usenet newsgroup is Internet discussion group on just about any topic you can imagine. There are more than 50,000 newsgroups and more are added all the time. Each newsgroup covers a particular topic, often alluded to in its name.
A newsgroup creates a discussion string or a series of related messages. Each message respond to an earlier message or addresses the overall newsgroup topic in some way. You can post your own message in response to the messages that interest you most.