City of technology: 2/5/12

Network Cables

9:49 PM By Miss Bee

There are 3 types of cables used in Networking;
Coaxial cable (RG-8/ RG-58)
Twisted Pair Cable (UTP/STP)
Fiber Optic

1. Coaxial cable (RG-8/ RG-58)
　There are 2 types of coaxial cables, RG-8 (Thick Net) and RG-58(Thin Net). These were used in physical Bus network.
RG-8:
It had a thick outer coating and was resistant to EMI.
But it was difficult to setup because the outer coating made it less flexible.
It used the AUI connector.
It could support 100 computers and Max distance of 500 meters.
RG-58:
It had a thinner outer coating which made it flexible and easier to setup.
It used the BNC connector.
It can support 30 computers and maximum distance of 185 meters.

2. Twisted Pair Cable (UTP/STP)

These are the commonly used cables in networking.
T.P cables come in different category and each category supports a different speed and distance. There can be 1, 2, or 4 pairs of cables according to category.　

3. Fiber Optic
This is a advanced type of cable which transfers data in form of light signals.
Light signals support much higher distances and speeds. Also light signals are completely immune toward EMI.
It is mainly used for long distance connections.
It is very used for long distance connections.
It is very expensive and difficult to handle. We required special training to be able to handle these cable.
Max distance 500meters.
(Note: no interference 100% guaranteed)

3. Gigabit Ethernet

9:43 PM By Miss Bee

This is the network that functions at the speed of 1000 mbps or 1 Gbps

A. 1000 Base TX

Specifications

Physical Topology : STAR

Logical topology : BUS

Cables : UTP CAT-6

Connectors : RJ-45

Max. Distance : 100 metres (HUB to Computer)

Max.Computers : 1024 per HUB

B. 1000 Base FX

Specifications

Physical Topology : STAR

Logical topology : BUS

Cables : Fiber Optic

Connectors : ST

Max. Distance : 100 metres (HUB to Computer)

Max.Computers : 1024 per HUB

2. Modern Ethernet

9:42 PM By Miss Bee

This is the network that functions at the speed of 100 mbps

A. 100 Base T4

Specifications

Physical Topology : STAR

Logical topology : BUS

Cables : UTP CAT3(4pairs)

Connectors : RJ-45

Max.Computers : 1024 per HUB

Max. Distance : 100 metres (HUB to Computer)

B. 100 Base FL

Specifications

Physical Topology : STAR

Logical topology : BUS

Cables : Fiber Optic

Connectors : SC

Max.Computers : 1024 per HUB

Max. Distance : 100 metres (HUB to Computer)

C. 100 Base T

Specifications

Physical Topology : STAR

Logical topology : BUS

Cables : UTP CA-5

Connectors : RJ-45

Max.Computers : 1024 per HUB

Max. Distance : 100 metres (HUB to Computer)

Ethernet Standards

9:40 PM By Miss Bee

Ethernet is the standard set by the IEEE organization. All companies that manufacture network devices and software follow these standards.

Using these devices we can create the following types of network:-

Basic Ethernet
Modern Ethernet
Gigabit Ethernet

1. Basic Ethernet:

This the network that functions at the speed of 10 mbps

A. 10 Base 2

Specifications

Physical Topology : BUS

Logical topology : BUS

Cables : RG-58

Connectors : BNC

Max.Computers : 30

Max. Distance : 185 metres

B. 10 Base 5

Specifications

Physical Topology : BUS

Logical topology : BUS

Cables : RG-8

Connectors : AUI

Max.Computers : 100

Max. Distance : 500

C. 10 Base T

Specifications

Physical Topolog : STAR

Logical topology : BUS

Cables : UTP CAT3

Connectors : RJ-45

Max.Computers : 1024 per HUB

Max. Distance : 100 metres (HUB to Computer)

Network Devices

9:34 PM By Miss Bee

1. Network adapters

Each computer must have a net work card installed inorder to

communicate in the network.

Network cards come according to speed and type of cable.
Also we require separate network cards for wireless networking.
It support speeds such as 10/100 mbps and 100/1000 mbps.

2. Repeaters

These are a 2 port device used to extend a single connection.
It can almost double the distance of the cable.

3. HUB.

These are the central device used in physical STAR networks.
It creates the interface through which we can connect multiple
computers to the network.
HUB come according to speed and number of ports.
Also separate HUB are required for UTP cables and Fiberoptic cables.

4. Bridge

Used for connecting two network segments together
Also it can perform traffic filtering among the segments.
It can remember the Physical addresses of computers in both segments and reduce collisions between these segments.

5. Switch

It is the same as bridge as it can remember Physical address and perform traffic filtering between segments.
Its main difference is that it can supprot multiple segment connection
where as bridge can only support two net segments.

6. Router

These are used for interconnecting different networks with eachother.
It can store logical address of networks and perform traffic filtering among those networks.

7. Brouter

This is a special kind of device as it can function both as bridge and Router.

TOPOLOGY (Network Wiring)

9:18 PM By Miss Bee

-Topology is of two types: Physical and logical.

-Physical Topology defines how the network is physically connected.

-Logically Topology defines how data is transferred within the network

Physical Topology: There are 5 types of physical topology.

1. BUS Topology (very old types not used anymore)

-Every computer is directly connected to central cable called BUS.

-The BUS acts as the communication medium for all network computers.

Advantages

It is very cheap and affordable.

Disadvantages

1. Very low speed (10mbps)

2. Number of computers is limited (Max 100)

3. Difficult to physical setup.

4. In case of cable breakage difficult to locate area of problem.

5. In case of cable breakage entire network will break.

2. Ring Topology (old types not used anymore)

-In this network the fist computer is connected to the second, second to third and finally the last computer is connected back to first computer.

-Ring can be of 2 types;

a. Single Ring: Data is sent in single direction only. (Clockwise or counter clockwise)

b. Dual Ring: Data is sent in both directions to increase data flow speed.

Advantages

No terminators are required.
It is slightly fault tolerant when compared to BUS.
Disadvantages
Very low speed. (10mbps)
Less computers. (Max 100)
In case of cable failure the network will either function slowly or completely crash.

3. Star Topology (Most common & popular now a days)

-In this network the central cable has been replaced by the central device called HUB/Switch.

-The central device allows more computers to be connected and supports higher speeds.

Advantages

High speed networking.
More number of computers.
Intelligent device auto manages the network.
Easier to located area of problem.
In case of cable failure only a single computer will be affected.
Disadvantages
If central device fails entire network will crash.
Lots of cabling is required.

4. Mesh Topology (old types not used anymore)

In this network all computers are directly connected to every other computer in the network.
Chances of this network crashing is almost impossible.

Logical topology

Logical bus

This is the commonly used logical topology
In this, when one computer sends a message it can be seen by all computers but only the destination computer will use it.
We can identify a logical BUS if we can send message at any time.

Logical Ring

This is used in token ring network.
In this, only one computer can send at a time. Other computers must wait.
We can identify logical ring if there are separate connections for sending and receiving.

Cellular (wireless)

This is the same as logical bus.
The only difference is that no physical connection is required.
The range of the WAP device is called cell. We can interconnect two or more cells.
Computers can be moved from one cell to another and still be able to communicate in the network.

Types of LAN

8:38 PM By Miss Bee

There are two basic types of LAN:

Peer to Peer (Workgroup)

Server/Client (Domain)

1. Peer to Peer (Workgroup)

(For example: a country without any Leader: means everyones is a leader and everyone has equal power. People will do whatever they like good or bad. In the same way, On a peer-to-peer network, every computer is equal and can communicate with any other computer on the network to which it has been granted access rights. )

Peer-to-peer networks are more common in small offices (LAN) or within a single department.

The advantage of a peer-to-peer (Workgroup) network is that we don't have to dedicate a computer to function as a file server. Instead, every computer can share its resources with any other.

Disadvantage of a peer-to-peer (Workgroup) network is that it has less security and less control because there is no centralization.

2. Server/Client (Domain)

(For example:a country with a king/Leader: means he will will control the whole country, people and everything. In the same way, On a Domain network, One computer will be used as server.

A server computer typically has faster processors, more memory, and more storage space than a client because it might have to service hundreds of users at the same time. A server is designed to share its resources among the client computers on the network.

Who are clients?

Clients are the user computer that receive/send through server computer.
A client system is a standard computer that is running an operating system such as WindowsXP, Windows VISTA, Windows Seven. These versions of Windows contain the client software that enables the client computers to access the resources that servers share.

To make a server computer we require a Server operating system such as Windows Server 2000, 2003 or Windows Server 2008.

Typically, servers are located in secured areas, such as locked closets or server rooms. The rest of the computers on the network function as clients and are used to access resources located on servers.

The main advantage of a Domain network is that it provides higher levels of security and more centralized control over client computers.

Types of Networks

7:58 PM By Miss Bee

Local Area Network (LAN)

The smallest office network is referred to as a local area network (LAN). A LAN is formed from computers and components in a single office or building.

Home Area Networks (HAN)

A home area network is really no different from a LAN. It often uses the same hardware components as a LAN, but a HAN is mainly used to share Internet access.

Wide area networks.

LANs in different locations can be connected by high-speed fiber-optic, satellite, or leased phone lines to form a wide area network (WAN).

The Internet.

The World Wide Web is the most visible part of the world's largest network, the Internet. The Internet is really a network of networks, all of which are connected to each other through the TCP/IP protocol. Programs such as web browsers, File Transfer Protocol (FTP) clients, and email clients are some of the most common ways users work with the Internet.

Intranets.

Intranets use the same web browsers and other software and the same TCP/IP protocol as the public Internet, but intranets exist as a portion of a company's private network. Unlike the Internet, the content is restricted to authorized company users only. An intranet is a private Internet.

Extranets.

Intranets that share a portion of their content with customers, suppliers, or other businesses, but not with the general public, are called extranets. As with intranets, the same web browsers and other software are used to access the content.

VPN:

This uses the public telephone line to create a virtual private network among users.

Network And Networking

7:44 PM By Miss Bee

A network is a group of two or more computers that intelligently shares resources with each other.

A network can be as small & simple as two computers or as large as the world's largest network, the Internet. It allows us to be able to access a remote resource as if it were a local resource.

(Intelligently sharing means that each computer that shares resources with other computers maintains control of that particular resource.)

What are Resources?
Any hardware device or software that can be shared in the network are called resources. These include the following;
File/folder
Printers
Disk Drives
Optical Drives
Modems (Internet Connection Sharing)
Scanners etc.

Advantages of network:
Reduces hardware costs by sharing expensive printers and other peripherals among multiple users
Multiple users can share access to software and data files.
Electronic mail (email) can be sent and received.
Multiple users can contribute to a single document using collaboration features.
Remote-control programs can be used to troubleshoot problems or show new users how to perform a task.
A single Internet connection can be shared among multiple computers
Requirements for a Network
Physical (cable) or wireless connections between computers
Every computer must have proper Network adapter cards
Centralized devices such as hub, switch to achieve network connections.
Software that enables resources to be shared with other PCs and controls access to shared resources, known as a network operating system
A common set of communications rules, known as a network protocol
Resources that can be shared, such as printers, disk drives, and CD-ROMs

Google Search

Network Cables

3. Gigabit Ethernet

2. Modern Ethernet

Ethernet Standards

Network Devices

TOPOLOGY (Network Wiring)

Types of LAN

Types of Networks

Network And Networking

Choose any

SEO

City of technology

Blog Archive

Site Meter

Web Traffic

Submit URL