Chapter 1 Basics of Networking & Designs of Simple Networks powered by DJ.
-
Upload
owen-norton -
Category
Documents
-
view
220 -
download
2
Transcript of Chapter 1 Basics of Networking & Designs of Simple Networks powered by DJ.
Chapter 1
Basics of Networking &
Designs of Simple Networks
powered by DJ
CHAPTER OBJECTIVES-
At the end of this Chapter you will be able to:
Understand Computer networking concepts.
Describe the purpose and functions of various
network devices.
Select the components required to meet a network
specification.
powered by DJ
What is a Network?
In general, the term network can refer to any
interconnected
group or system. More specifically, a network is any
method of
sharing information between two systems (human,
electrical or
mechanical).
Introduction to Computer Networking Concepts
Figure 1: A Simple Network Example
powered by DJ
Classification of Network
1. According to the size of the
Network:
LAN
MAN
WAN
PAN
CAN2. According to type of connection
used:
Wired Network
Wireless Networkpowered by DJ
3. According to the functional relationship(Network Architecture):
Peer to Peer Network
Client Server Network
powered by DJ
According to the Size of the Network
LAN (Local Area Network)
A Local Area Network is a group of computers and
network
communication devices within a limited geographic
area, such as
an office building. For example, a library will have a
wired or
wireless LAN for users to interconnect local
devices(e.g., printers,
and servers).
Local area networking uses switches, bridges and/or
repeaters,
and hubs to interconnect LANs and increase overall
size. Routers
are used to connect a LAN to a WAN or MAN.powered by DJ
Figure 2: A Simple LAN Illustration
They are characterized by the following:High data transfer speeds.
Generally less expensive technologies Limited geographic areaSecurity Scalability Reliability
powered by DJ
MAN (Metropolitan Area Network)
WAN (Wide Area Network)
A WAN is a data communications network that covers a
relatively broad geographic area (i.e. one country to
another country) and that often uses transmission
facilities provided by common carriers, such as
telephone companies. They are generally connected with
each other using routers.
A Metropolitan Area Network is a network that connects two or more Local Area Networks or Campus Area Networks together but does not extend beyond the boundaries of the immediate town, city, or metropolitan area. A MAN can range anywhere from 5 to 50km in diameter.
powered by DJ
They are characterized by the following:Multiple interconnected LANs. Generally more expensive technology. More sophisticated to implement than LANs. Exist in an unlimited geographic area.
Figure 3: An Example of WANpowered by DJ
Personal Area Network (PAN)
Storage Area Network (SAN)
A personal area network (PAN) is a computer network used for communication among computer devices close to one person. Some examples of devices that may be used in a PAN are printers, fax machines, telephones,scanners.The reach of a PAN is typically within about 20-30 feet (approximately 6-9 Meters).
We have a lot of data in the form of audio and video. We need to store data for quick access and transfer on special storage devices. SAN may be referred to as a sub network or special purpose network. Its special purpose is to allow users on a larger network to connect various data storage devices with clusters of data servers.
powered by DJ
Virtual Private Network (VPN) VPN is a private network that lets you access public networks remotely. VPN uses encryption and security protocols to retain privacy while it accesses outside resources by creating a virtual network.
powered by DJ
According To the Type of Connection Used
Wired Network: A network that connects devices using cables (wires) like Coaxial Cable, Twisted pair Cable, Optical Fiber Cable etc. Wireless Network: A network that connects devices using wireless technologies like Bluetooth, infrared, radio frequency etc.
powered by DJ
According To the Functional
Relationship (Network
Architecture) Peer to peer network (Workgroup) A workgroup is a collection of computers on a LAN that share common resources and responsibilities. Workgroups provide easy sharing of files, printers and other network resources.
Client-Server Network (Domain) A Domain is a “Network Architecture” in which each computer or process on the network is either a client or a server. servers are powerful computers or processes dedicated to managing disk drives (file servers), printers (print servers) etc. Clients are PCs or workstations on which users run applications. Clients rely on servers for resources, such as files, devices, and even processing power.
powered by DJ
Network Topologies
Topology refers to the way in which the network of computers is connected. The choice of topology is dependent upon---
Type and number of equipment being used Planned applications and rate of data transfers Required response times Cost
Types of Network TopologiesPhysical Topology: Physical topology defines how devices are connected to the network through the actual cables that transmit data(physical structure of the network)
Logical Topology: Logical Topology (also referred to as Signal Topology) is a network computing term used to describe the arrangement of devices on a network and how they communicate with one another.
powered by DJ
1. BUS Topology
Figure 4: Bus Topology Representation
In a BUS topology:
A single cable connects each workstation in a linear, daisy- chained fashion. Signals are broadcasted to all stations, but stations only act on the frames addressed to them.
powered by DJ
2. RING Topology
Figure 5: Ring Topology Representation
In a RING topology:
Unidirectional links connect the transmit side of one device to the receive side of another device. Devices transmit frames to the next device (downstream member) in the ring.
powered by DJ
3. STAR Topology
Figure 6: Star Topology Representation
In a star topology:
Each station is connected to a central Hub or Switch (concentrator) that functions as a multi-port repeater. The HUB broadcasts data all of the devices connected to it.The Switch transmits the data to the dedicated device for which the data is meant for.
powered by DJ
Basic Networking Devices1. Network Interface Cards
A Network Interface Card (NIC)
A network card, network adapter or NIC (network interface card) is a piece of Computer hardware designed to allow computers to communicate over a computer network. It provides physical access to a networking medium and often provides a low-level addressing system through the use of MAC addresses. It allows users to connect to each other either by using cables or wirelessly.powered by DJ
2. Repeaters
Examples of Repeater
A repeater is an electronic device that receives a signal and retransmits it at a higher level or higher power
powered by DJ
3. HUBS
Example of Hubs
A hub (concentrator) contains multiple ports, which is used to connect devices in a star topology. When a packet arrives at one port, it is copied to all the ports of the hub. But when the packets are copied, the destination address in the frame does not change to a broadcast addresspowered by DJ
4. Bridges
A Common Bridge
A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges do not promiscuously copy traffic to all ports, as hubs do, but learn which physical addresses are reachable through specific ports
powered by DJ
5. Switches
Switches
A switch is a device that performs switching. Specifically, it forwards and filters OSI layer 2 datagram (chunk of data communication) between ports (connected cables) based on the Physical-Addresses in the packets
A switch normally has numerous ports than Bridge.
powered by DJ
6. Routers
Two Modern Routers
Routers are networking devices that forward data packets along networks by using headers and forwarding/routing tables to determine the best path to forward the packets. Routers work at the Internet Layer of the TCP/IP model or layer 3 of the OSI modelpowered by DJ
WAN Infrastructure Devices
As with LAN, there are numerous devices associated with data transmission across a WAN. Together these devices create the infrastructure of a functional WAN. These devices include:
Router
ATM Switch
Modem and CSU/DSU
Communication Server
Multiplexer
powered by DJ
ATM Switch
ATM Switches provide high-speed transfer between both LANs and WANs
ATM Switch in the middle
powered by DJ
Modem (modulator / demodulator)
Modems convert digital and analog signals. At the source, modems convert digital signals to a form suitable for transmission over analog communication facilities (public telephone lines). At the destination, modems convert the signal back to a digital format.
An Early Modem
powered by DJ
Multiplexer
A Multiplexer combines multiple signals for transmission over a single circuit. This allows for the transfer of various data simultaneously, such as video, sound, text, etc.
Multiplexing
powered by DJ
Communication Servers
Communication Servers are typically dial-in/out servers that allow users to dial in from remote locations and attach to the LAN.
Dial-up Communications
powered by DJ
THANK YOU
powered by DJ