BMET HOSA Systems and Networking

Network

term network means two or more connected computers that can share resources like data and applications, office machines, an Internet connection, or some combination of these.

Consists of both hardware and software

Computer Hardware

• Central Processing Unit

• Motherboard

• Radom- Access Memory

• Read- Only Memory

• Hard Drive

• Peripheral

Central Processing Unit

Is the computer’s brain electronic machinery that carries out instructions from programs that allow a computer or other device to perform its tasks.

Motherboard

Is the backbone that ties the computer's components together at one spot and allows them to talk to each other.

Random- Access Memory

Is a form of computer memory that can be read and changed in any order.

Read-Only Memory

Is a non-volatile memory type. This means it receives data and permanently writes it on a chip, which lasts even after you turn off your computer. The data is coded not to be overwritten

Hard Drive

Is where all your permanent computer data is stored. Whenever you save a file, photo, or software to your computer, it's stored in your hard drive.

Peripheral Device

Is an auxiliary device used to put information into and get information out of a computer

SRAM

• static, it does not need to be refreshed

• uses less power, and the memory can be accessed quickly

• often installed in pairs

DRAM

• dynamic and needs to be refreshed often

• heaper and offers greater memory capacity

RAM

• RAM handles your temporary memory (all the data you are currently using)

• The more RAM you have the better your computer will do in terms of performance.

Operating System (Software)

• File management layer translates logical file requests from command shell into physical I/O requests

• Resource management –resolve conflicts among programs

• Memory management load and schedule

• Monitor system arbitrator and general management

• OS must load and execute a program

• Must get programs from storage location from I/O into memory which means it has to provide and allocate space

• Provide CPU time for execution

Application Software Examples

Acts as an interface for application programs

Software that enables the functions and use of a device

Accomplish user tasks

Examples: Word processing,

Spreadsheet

Data

Types of Cabling

• Coaxial

• Twisted Pair

• Fiber Optic

• Plenum Rated

Coaxial cable

contains a center conductor made of copper surrounded by a plastic jacket with a braided shield. 

Twisted-pair cable

multiple individually insulated wires that are twisted together in pairs.

Unshielded Twisted Pair Cable

Cable without outer shielding

Used in ethernet networks

Fiber Optic

Because fiber-optic cable transmits digital signals using light impulses rather than electricity, it’s immune to EMI and RFI.

Plenum Rated

The plenum is an open space found above a building’s dropped ceilings.

Plenum spaces often house telephone and network communication cables.

Plenum rated cables need to be coated in flame-retardant, low smoke materials such as polyvinyl chloride (PVC).

Topologies

Connected computers and devices come in different configurations to support needs, requirements, and security called Topology.

Ring Topology

All devices are connected to each in a virtual ring. 

It does not have to be terminated.

Star Topology

Most popular topology, each device has a dedicated connection to the hub or switch.

Bus Topology

Signals from each device travel on a bidirectional bus. 

Utilizes CSMA/CD software the sense when a line is busy. 

Cabling has to be terminated at the ends.

Mesh Topology

Each computer has a dedicated connection to every other computer on the network.

Hybrid Network

Are designed to take advantage of the strengths of each combined network. Star/Bus and Star/Ring are two examples of Hybrid Networks.

Carrier Sense Multiple Access/Collision Detection

• Is software that senses when the line is busy, to avoid collisions and loss of data.

• Listens to see if the line if it is being used, systems waits for a random amount of time then retries.

Personal Area Network

used for communicating among computers and computer devices (including telephones) nearby around a few meters within a room.

It can be used for communicating between the devices themselves or for connecting to a larger network such as the internet.

Local Area Network

A LAN is a network that is used for communicating among computer devices, usually within an office building or home

LAN’s enable the sharing of resources, such as files or hardware devices, that may be needed by multiple users 

LAN Nodes

A node is defined to be any device connected to the network. 

This could be a computer, a printer etc.

LAN Hub

Is a networking device that connects multiple segments of the network together

Network Interface Card

Is the circuit board that is used to connect computers to the network. 

In most cases, this is an Ethernet card plugged in a computer’s motherboard.

Network Operating System

Is the software that enables users to share files and hardware and communicate with other computers. 

Resource Sharing

In a LAN is accomplished with different access methods. 

These include:

•Token based access

•CSMA/CD

Metropolitan Area Network (MAN)

A network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN)

Wide Area Network (WAN)

A geographically distributed network composed of local areas networks (LANs) joined into a single large network using services provided by common carriers.

Wireless Networking

A wireless network is a computer network that uses wireless data connections between networks nodes.

Wireless networks use ___________ waves to enable these devices to communicate with each other.

 radio frequency (RF)

Hardware Wireless Networks

Wireless NIC

Wireless Access point

Software Wireless Networks

Device driver to talk to the wireless NIC and configuration utility.

Repeaters

Repeaters are simple devices that act as signal amplifiers.

Repeaters extend or boost signals by forwarding wireless signals from the router to cover a larger area

Network Switches

A network switch connects users, applications, and equipment across a network to communicate with one another and share resources. 

Network switches act as central connection points for network devices.

Routers

Routers connect computers and other devices to the Internet; routers transfer information between networks internally and externally.

Transmission Control Protocol/Internet Protocol (TCP/IP)

The 5-layer model associated with networks is commonly known as the TCP/IP model. It is a conceptual framework that standardizes the functions of a telecommunication or computing system into five abstraction layers. The layers, from the lowest to the highest, are as follows:

Physical

Data Link

Network

Transport

Application

(TCP/IP) Layer 1

Physical - Bits ‘on the wire’

This layer deals with the physical connection between devices. It defines the hardware aspects, such as cables, switches, and network interface cards. 

(TCP/IP) Layer 2

Data Link - Data transfer between neighboring network elements

PPP

ETHERNET

The Data Link Layer is responsible for the reliable transmission of data frames between devices on the same network. It also handles error detection and correction at the local network level. 

(TCP/IP) Layer 3

Routing of datagrams from source to destination

IP

ROUTING PROTOCOLS

The Network Layer is concerned with logical addressing and routing. It determines the best path for data to travel from the source to the destination across different networks. 

(TCP/IP) Layer 4

Transport - Host-host data transfer

TCP

UDP

The Transport Layer ensures end-to-end communication and data flow control between devices. It is responsible for reliable and ordered delivery of data, and it includes protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). 

(TCP/IP) Layer 5

Application - Supporting network applications

FTP

SMTP

HTTP

The Application Layer is the topmost layer and is closest to the end-user. It provides network services directly to applications and end-users. Application Layer protocols define the format and semantics of data exchanged between networked programs in the same or different devices 

Bit

A bit is one digit, either a 1 or a 0

Byte

A byte is 7 or 8 bits, depending on whether parity is used. 

For the rest of this chapter, always assume a byte is 8 bits.

Octet

An octet, made up of 8 bits, is just an ordinary 8-bit binary number. 

Network Address

This is the designation used in routing to send packets to a remote network—for example:

Broadcast Address

The broadcast address is used by applications and hosts to send information to all hosts on a network.