Chapter 13: IT infrastructure and computer networks

Infrastrucuture

the fundamental physical and organizational structures and facilities needed for the operation of a society or enterprise

IT infrastrucutre

includes the essential components, systems and resources that enable IT services within an organization

Small-scale computing

-Limited hardware resources

-Basic software applications

-Minimal IT infrastructure management

Large-scale computing

-Extensive hardware infrastructure

-Complex network architecture

-Sophisticated software systems

-Robust IT infrastructure management

Types of computers used in large computing

-Supercomputers

-Mainframes

-Server computers

Supercomputers

The largest and fastest computers, capable of storing and processing tremendous volumes of data.

Mainframes

Large, powerful computers used by large organizations for critical applications, bulk data processing, ERP and transaction processing

Server

A powerful computer/software tha provides services, data, opr resources to other computer, called clients over a network

Types of servers

rack server, blade server, and tower server

Rack server

Servers mounting in racks, balancing space and performance

Tower servers

Standalone servers are similar to desktop PCs, but with more powerful components

Blade servers

Compact, modular servers that fit into a chassis, sharing power and cooling

What we need servers for

-Centralized resource management

-Data storage and sharing

-Application hosting

-Security and access control

-Scalability and flexibility

-Reliability and redundancy

-Remote access and management

Client

A device/software that requests and uses services, resources or data provided by a server

What clients are used for

-Requesting services

-Consuming resources

-User interaction

-Network communication

Components of IT infrastructure

-Hardware

-Software

-Facilities

-Networking

-Data centres

Data centres

A location that hosts several servers

Design considerations of data centres

-Power supply

-Cooling system

-Redundancy assurance

Types of network applications

-Communication applications

-File sharing and collaboration platforms

-Web services

-Social networking platforms

-Remote access

-Internet of things

Interconnectivity

Enables seamless communication and data exchange

Interdependence

Components rely on each other for effective function

Monitoring and management

Ensures optimal functionality and security

Types of IT infrastructure

Traditional infrastructure and cloud infrastructure

Traditional IT infrastructure

Infrastructure that uses conventional hardware and software components

Cloud IT infrastructure

Infrstructure that is accessible via the internet with virtualization

Network

A collection of interconnected computers, devices, or systems that share resources and communicate with each other

Network categories

-Personal Area Network (PAN)

-Local Area Network (LAN)

-Metropolitan Area Network (MAN)

-Wide Area Network (WAN)

-Enterprise Private Network (EPN)

PAN (Personal area network)

A network organized around an individual person within a single building

Local Area Network

A network that connects computers and devices withinnn a limited area such as a home, school, or office building

Metropolitan Area Network

A network, often used by businesses to connect branches within a city, that spans a city or a large campus, connecting multiple LANs

Wide Area Network

A network that covers a broad area and represents a largest example of a WAN

Enterprise Private Network

A network built by an enterprise to connect its various sites to share resources and information securely

Network device categories

-Network interface card

-Access network components

-Access point

-Network core components

-Firewall

-Modem

Network Interface Card (NIC)

Provides the physical interface between a computer and a network

Access Network Components

They facilitate connectivity between end devices and the rest of the network. They operate at layer 2 of the OSI model and are responsible for forwarding data frames between devices within the same LAN

Access point

Provides wireless connectivity to devices, allowing them to connect to a wired network via WI-FI.

Network core components

operate at layer 3 and facilitate communication between different networks by forwarding data packets based on network layer addresses

Modem

A communications hardware device that facilitates the transmission of data.

Types of modem

-Dial-up modem

-DSL Modem

-Cable modem

-Fiber optic modem

-Satellite modem

-Cellular modem

WI-Fi router

Sets up and manages a local area network, directing traffic among connected devices and between the LAN and the internet

Wireless antenna

Transmit and receive radio waves

Mesh network

Decentralized topology in which nodes interconnect directly

Network protocols

set of rules that govern how devices format, transmit, and receive data

Routers

Forward data packets between networks based on IP addresses (can combine functions of hubs, switches and modems)

Switches

They connect multiple devices within a LAN, operating at OSI layer 2 and use MAC addresses to forward frames only to their intended destination

Bridge

Operates at OSI layer 2 to connect network segments into a single LAN

Media Access Control (MAC) address

a 48-bit physical identifier assigned to each NIC. The first six digits are the organizationally unique identifier, and the last 6 digits are the device-specific identifier

Network media

The physical/wireless channels that carry data between devices and to the internet

Guided media

Signals travel within solid materials

Unguided media

Signals propagate freely through the air

Guided media types

-Twisted pair cable

-Coaxial cable

-Fibre-optic cable

Attributes of wireless network media

-Signal: radio

-Max distance: 100 ft

-Max bandwidth: 1.3Gbps

-Key issue: Throughput lower in practice

Twisted-pair copper cable attributes

-Signal: Electricity

-Max distance: 330 ft

-Max bandiwth: 1 Gbps

-Key issue: Susceptible to EMi

Fibre-optic cable attributes

-Signal: light

-Max distance: 50 mi

-Max bandiwth: 26 Tbps

-Key issue: High installation cost

Network topology

The arrangement of different elements in a computer network

Types of topologys

-Bus

-Star

-Mesh

-Ring

Bus topology

A single shared cable that requires terminators at both ends to prevent reflections (data transmission errors)

Star topology

Devices connect to a central hub/switch. data passes through the hub before reaching the intended devices

Ring topology

Each device is connected to two other devices, forming a circular network. Data travels in one direction around the ring

Mesh topology

Every device is connected to every other device in the network

Advantages and Disadvantages of Bus Topology

Easy to implement and extend and requires fewer cables but the whole network fails, if the central cable fails and is limited by the cable length and the number of stations

Advantages and Disadvantages of Star Topology

easy to install and manage, and failure of one node does not affect the whole network but the whole network is affected if the central hub fails, and it requires more cable than bus topology

Advantages and Disadvantages of Ring Topology

Data packets travel at high speed, and there are no data collisions, but the whole network can be affected if one device fails, and it's difficult to troubleshoot

Advantages and Disadvantages of Mesh Topology

Highly reliable and redundant and data can be transmitted simultaneously across multiple devices but its expensive and complex to install and requires a lot of cabling

Data transmission steps

1. Preparing the data

2. Breaking the data into packets

3. Addressing the packets

4. Transmitting the packets

4. Receiving the packets

5. Reassembling the data

6. Delivering the data

IP address

A unique identifier assigned to each device connected to a network allows devices to communicate with each other by specifying the source and destination of data packets

IPv4 address

32-bit number shown in dotted decimal as four octets, with each octet ranging from 0-255

Subnet mask

Masks IP bits to separate the network portion from the host portion

Class A Address

-First bit is set to 0

-First octet ranges from 1-126

-Large networks with up to 16 million hosts

-Default subnet mask: 255.0.0.0

Class B Address

-First two bits are set to 10

-First octet ranges from 128-191

-Medium-sized networks with up to 65,000 hosts

-Default subnet mask: 255.255.0.0

Class C Address

-First three bits to 110

-First octet ranges from 192-223

-Small networks with up to 254 hosts

-Default subnet mask 255.255.255.0

DHCP

Protocol that dynamically assigns IP, subnet mask, gateway, and DNS to hosts.

IPv6

128-bit hex address in eight groups

The internet

A global network of networks that connects billions of devices using protocols

Origins of the Internet

Started in 1969 as ARPNET (Advanced Research Projects Agency Network), then evolved into NSFNET (National Science Foundation Network) in 1987

WWW

A service on the internet that is a collection of websites and web pages

Domain Name System (DNS)

A distributed directory that maps human names to IP addresses

nslookup

Command used to check the IP of a domain name

layers of the TCP/IP protocol

-Application layer

-Transport layer

-Internet layer

-Network interface layer

Application layer

Provides protocols and services directly to end-users, enabling applications to access network services

Hypertext Transfer Protocol (HTTP)

a protocol for computers to request and share the pages that make up the world wide web on the Internet

Transport Layer

Makes sure data gets from one device to another correctly

Key protocols for transport layer

TCP and UDP

TCP

Makes sure every piece of data is delivered in the right order reliably

UDP

Sends data quickly, but doesn't guarantee that it arrives

Internet layer

Figures out the best path for data to travel across multiple networks to reach its final destination

Network interface layer

gets data from one device to another over a specific network

Key protocol for the network interface layer

-MAC address

-Physical layer: sends the actual bits of data

web browser

Software application used ot access and display information on the World Wide Web

Encryption

Process of converting readable plaintext into unintelligible ciphertext so only authorized parties can read it

Uses for cryptography

-Data integrity

-Entity authentication

-Data origin authentication

-Non-repudiation

Cryptosystem (cypher system)

A system that provides both encryption and decryption services

Types of Cryptosystems

-Symmetric key encryption

-asymmetric key encryption

-Hashing

-Classical ciphers

Hashing

converting a string of characters such as letters, numerals or symbols by applying a mathematical formula

Symmetric key encryption

Same key is used to encrypt and decrypt

Asymmetric key encryption

Uses a public key for encryption and a private key for decryption

Types of classical ciphers

-Substitution ciphers: Replacing each plaintext symbol with another symbol

-Transportation ciphers: Rearanging the order of letters

Ceaser cipher

A type of substitution cipher that rotates the alphabet by three letters

Not studied (98)

You haven't studied these terms yet.