OV 1 - 1 Copyright © 2013 Logical Operations, Inc. All rights reserved. Network Theory Networking...

OV 1 - 1Copyright © 2013 Logical Operations, Inc. All rights reserved.

Network Theory

Networking Terminology Network Categories Standard Network Models Physical Network Topologies Logical Network Topologies


Computer Networks

Computers connect to communicate and share resourcesComputers connect to communicate and share resources


Network Components

Network Component Description

DeviceHardware such as computers, servers, printers, fax machines, switches, and routers.

Physical mediaMedia that connects devices to a network and transmits data between the devices.

Network adapterHardware that translates data between the network and a device.

Network operating system

Software that controls network traffic and access to common network resources.


Nodes

Redistribution pointRedistribution point

EndpointsEndpoints

Switch


The Network Backbone

Backbone


Types of Network Backbones

Network Backbone

Description

SerialConsists of multiple switches connected by one backbone cable. Typically not scaled for enterprise-wide use.

Distributed/ hierarchical

Consists of multiple switches connected serially to hubs or routers. Due to their hierarchical structure, these networks can be easily expanded without a significant cost impact.

Collapsed Uses a router or switch as the nexus for several subnetworks.

Parallel

Suits enterprise-wide applications. Like the collapsed backbone network, the parallel backbone network uses a central router or switch but augments the dependent switches with multiple cable connections.


Servers

General purposeGeneral purpose DedicatedDedicated

Server 2Server 1

Client 1 Client 2


Clients

Server

Client 1 Client 2

Maintains resources and performs its own

processing

Maintains resources and performs its own

processing


Peer Computers

Peer 1 Peer 2

Peer 3

Acts as both client and server

Acts as both client and server


Host Computers

Client 1

Host

Client 2

Provides processing andstorage capabilities

Provides processing andstorage capabilities


Terminals

Terminal

Host

Client

No processoror memory

No processoror memory


LANs

Nodes connected with cablesNodes connected with cables


WANs

Internet


Network Coverage Areas

Network Category Description

MAN Covers an area equivalent to a city or other municipality.

CANCovers an area equivalent to an academic campus or business park. A CAN is typically owned or used exclusively by an entity.

PANConnects two to three computers with cables and is most often seen in small or home offices.

WPAN

Connects wireless devices in very close proximity but not through a Wireless Access Point (WAP).

Infrared and Bluetooth are some technologies used for connecting devices in a WPAN.


The Internet

74.6.1.246209.116.88.4

131.107.2.6138.45.9.121

IP addressIP address


Intranets

Internet

IntranetIntranet

192.168.1.23

192.168.1.20

192.168.1.21

192.168.1.100

192.168.1.1

192.168.1.22


Extranets

Client 1 Client 2

Client 3

Clients access the organization’s

resources

Clients access the organization’s

resources


Enterprise Networks

LAN

Remote User

Network Operations Center

Headquarters

Branch Office

Internet


Network Models

Centralized Model


Segments

Segment 1

Segment 2

Router

Devices have common access to the networkDevices have common access to the network


Centralized Networks

Connect to the host via terminals or terminal emulators

Connect to the host via terminals or terminal emulators


Client/Server Networks

Server

Client 1 Client 2

Clients perform basic end-user tasks

Clients perform basic end-user tasks

Server provides processing power, management services, and administrative functions

Server provides processing power, management services, and administrative functions


Peer-to-Peer Networks

Resource sharing, processing, and communications control are completely decentralized

Resource sharing, processing, and communications control are completely decentralized


Mixed Mode Networks

Host

Client/Peer

Server Client/Peer

Clients with terminal emulatorsClients with terminal emulators

Incorporates elements from more than one network model

Incorporates elements from more than one network model


Topology

Describes a network's physical wiring layoutDescribes a network's physical wiring layout

Describes the paths through which data flowsDescribes the paths through which data flows


Point-to-Point Connections

A direct connection between two nodes on a network

A direct connection between two nodes on a network


Multipoint Connections

Receiver Detector Sender Detector

Each multipoint connection has more than two endpointsEach multipoint connection

has more than two endpoints


Radiated Connections

Wireless point-to-point or multipoint connection

Wireless point-to-point or multipoint connection


The Physical Bus Topology

T-connectorT-connectorTerminatorTerminator

Nodes are arranged in a linear format

Nodes are arranged in a linear format


The Physical Star Topology

Switch

Individual nodes send data to the connectivity device

Individual nodes send data to the connectivity device

Uses a central connectivity deviceUses a central connectivity device


The Physical Ring Topology

Has upstream and downstream neighbors

Has upstream and downstream neighbors

Flow of data is unidirectional to avoid collisions

Flow of data is unidirectional to avoid collisions


The Physical Mesh Topology

Each node is directly connected to every other node

Each node is directly connected to every other node


The Physical Tree Topology


Hybrid Topologies

Star-bus topology


Types of Hybrid Topologies

Hybrid Topology Formed By

Star-bus Linking the central nodes of star networks using a common bus.

Star-of-starsConnecting the central nodes of two or more star networks with a new common node.

Star-ringConnecting the central nodes of multiple star networks in a ring fashion.


The Logical Bus Topology


Data Transmission on a Bus

Nodes listen passively to the channel

A node transmits data when the bus is free

Sends out a broadcast alert

Destination node picks up the transmission

In case of non-receipt of data, the bus terminates

the transmission

Collision occurs; nodes wait before retransmitting data


The Logical Ring Topology

Receives data from its upstream neighbor and

retransmits to downstream neighbor

Receives data from its upstream neighbor and

retransmits to downstream neighbor


The Logical Star Topology


Reflective Questions

1. In your opinion, what are the considerations for choosing between the different topologies to implement in your network?

2. Describe any background experience you have working with LANs, WANs, or other types of networks.

Date post:	03-Jan-2016
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