Answer each of the following: 1. O) (a) What is a network? (b) What are the elem
ID: 3724883 • Letter: A
Question
Answer each of the following: 1. O) (a) What is a network? (b) What are the elements and their functions of a typical network? Explain each one. (c) What devices are used in layers 1-3? (d) What is a message called in layer 2? Layer 3? (Gi) (a) What is a signal? (b) What is propagation? (c) What is a transceiver? 2. (a) Describe the traditional Peer-to-Peer network model. What are the advantages and disadvantages? What is a common way to share resources? b) Discuss the basic elements common to all Client/Server Networks and the common network topologies including the advantages and disadvantages. 3. Discuss the following services a. Access Services b. Communications Services c. Management Services 4. (a) Describe the OSI Reference Model -the 7 layers and their functions. Draw a figure and label each layer. (b) Describe the hybrid model (from the Xerox copy'on BlackBoard). Explain the standards used in TCP/IP and Hybrid ModelsExplanation / Answer
1)a)Answer:
Network:
A network, in computing, is a group of two or more devices that can communicate. In practice, a network is comprised of a number of different computer systems connected by physical and/or wireless connections. The scale can range from a single PC sharing out basic peripherals to massive data centers located around the World, to the Internet itself. Regardless of scope, all networks allow computers and/or individuals to share information and resources.
Computer networks serve a number of purposes, some of which include:
1)b)Answer:
Basic elements of a computer network include hardware, software, and protocols. The interrelationship of these basic elements constitutes the infrastructure of the network.
A network infrastructure is the topology in which the nodes of a local area network (LAN) or a wide area network (WAN) are connected to each other. These connections involve equipment like routers, switches, bridges and hubs using cables (copper, fiber, and so on) or wireless technologies (Wi-Fi).
If we think of a network as roads, highways, rails, and other means of transport, the network protocols are the "traffic rules." The network protocols define how two devices in the network communicate. The specification of the network protocols starts with the electrical specifications of how a networking device is connected to the infrastructure. For example, line voltage levels, carrier signals and the designation of which line might be used for what types of signals must all be specified. Building up from there, network protocols include such specifications as the methods that can be used to control congestion in the network and how application programs will communicate and exchange data.
A popular method of documenting network protocols is to use a layered network architecture model. Network architecture models separate specific functions into layers, which collectively form a network stack. While a protocol consists of rules that define characteristics for transporting data between network nodes, the layered model separates the end-to-end communication into specific functions performed within each layer.
Ideally, the layers are isolated from each other: each layer does not need to know how the layer below it functions. All a layer needs to know is how to interact with the layers adjacent to it. You can learn more about network layers in the topic on network layers and protocols.
Today, TCP/IP is by far the most dominant suite of networking protocols. Prior to TCP/IP, SNA was arguably the dominant protocol suite. There is some irony here, because TCP/IP is the older of the two protocols. Many networks in larger organizations are using both of these protocol suites. As with most networking protocols, both SNA and TCP/IP are layered protocol stacks.
Some of the basic hardware components that can be used in networks include:
1)c)Answer:
Devices are used in 1-3 layers:
Devices - Layer 1:
Hubs
NIC (Layers 1 & 2)
Media: Coax, Fiber, Twisted Pair, Wireless
Layer 2:
Bridges
Switches
NIC (Layers 1 & 2)
Layer 3:
Routers
1)ii)
Answer:
Signal:
A signal is an electrical or electromagnetic current that is used for carrying data from one device or network to another.
It is the key component behind virtually all:
A signal can be either analog or digital.
Typically, a signal is created when a command or data is sent to a device. It has implementation in electrical and electronic components as well, but it mainly refers to analog and digital communication technologies and devices. Each signal carries data in some form. The data is fed into the signal using analog or digital modulation techniques, depending upon the source and destination device and/or medium.
Besides communication devices that broadcast a signal externally to the host system, signals are also used to communicate and send instructions by:
This definition was written in the context of Electronics
b)Propagation:
Propagation literally means to reproduce or spread; in wireless networks, signal propagation refers to the radiation of an radio wave through the air and intervening objects. To learn some of the basics about radio signal propagation, check out these primers from Breezecom and SSS Online.
c)Transceiver:
A transceiver (TRX) is a device which can transmit and receive signals. Usually, a transceiver contains both a transmitter and a receiver, both of which share common circuitry. However, if the transmitter and receiver only share a common housing and nothing else, the device is called a transmitter-receiver. Transceivers are extremely important in the history of technology, as they have paved the way for many inventions such as two-way radios, mobile phones and the internet.
There are two main types of radio transceivers: full duplex and half duplex. In a half-duplex transceiver, when a radio transceiver is transmitting the message, the receiver portion is disabled. As both the parts share the same components, including the same antenna, the parts cannot transmit and receive signals at the same time. Thus, receiving cannot be done while transmitting, even though sometimes both operations may take place at the same frequency. An example of use of such a system is two-way radios, also known as walkie-talkies, which use “push to talk” functions.
In full-duplex transceivers, the transceiver can receive signals during transmissions. However, in such transceivers, the transmitter and receiver work at completely different frequencies. This disallows any kind of signal interference to occur. Many modern devices, including mobile phones and devices using satellite communication, use this technology.