Network Fundamentals

Network Fundamentals

  • not confined to computers or internet

  • Networks = Encompass a diverse range of connections extending to both wireless networks (e.g wifi, cellular) and wire networks(e.g. ethernet, fibre optic)

  • Networks facilitate a seamless flow of data

  • PAN = Personal Area Network (e.g. smartwatch to smartphone via bluetooth)

  • LAN = Local Area Network (e.g. wifi at home connecting tablet to internet)

  • In the past there were different networks for different types of data (e.g. network for analogue phones, for digital data, for video for tv)

  • Present day networks can handle voice, digital and video data on one connection.

  • High availability and uptime are very important on networks

  • the 5 9s of availability is a standard up time, it is 99.999% of uptime. This means only 5 minutes of downtime a year

  • All data treated as packets within the IP system

  • Networks always growing in modern world = challenge to maintain 5 9s of availability

Network Components

  • purpose of network is to get data from one machine to another

Clients

  • devices that users access the network with (e.g. smartphones, laptops, smart tvs etc.)

Servers

  • provide resources to the network (e.g. email servers, web servers, file servers etc.)

  • exist on dedicated hardware, or software that enables device to act as a server

Hubs

  • Older network devices that connect other devices like clients and server over a local area network

  • limitations - increased network errors due to broadcasting nature

  • created a long time ago - developed into bridges and then switches, which we use today

Switches

  • “Smarter hubs” that provide more security and more efficient bandwidth utilisation

Wireless Access Points (WAPs/APs)

  • Allow wireless devices to connect to a wired network

  • broadcast data using radio frequency wave instead of cable

  • prevalent in homes/offices etc.

Routers

  • Used to connect different networks together

  • Modern routers rely on the Internet Protocol to route the traffic across the network

Firewalls

  • Security barriers between internal networks and the external world (usually the internet)

  • monitor incoming and outgoing traffic based on predetermined security rules by using access control lists

  • can be hardware based, software based or combination of both

Load Balancers

  • Devices or software that distribute network or application traffic across multiple servers

  • ensures that no single server has too much demand, meaning more reliability and performance

Proxy

  • Acts as an intermediary between a user’s device and the internet

  • uses web filtering, shared network connections and data caching to improve performance

  • Provides enhanced security and privacy by hiding real IP address and limiting exposure to the internet

Intrusion Detection Systems (IDS) & Intrusion Prevention Systems (IPS)

  • IDS - Detect unauthorised access or anomalies and alert administrators

  • IPS - Detects threats AND takes action to prevent intrusion (e.g. blocking intrusion or dropping harmful packets)

Controllers

  • In Software-Defined Networking (SDN) context, these are central units used to manage flow control to networking devices

  • means admins can control behaviour of switches and routers through software, providing flexibility and efficiency

Network-attached Storage (NAS) Devices

  • Dedicated file storage system that provides data access to a heterogeneous group of clients

  • connected to network, allow data storage and retrieval from centralised location for authorised users and their clients

Storage Area Networks (SAN)

  • High-speed network that provides access to consolidated block-level data storage

  • designeed to handle large volumes of data, used to make disc arrays and tape libraries accessible to your servers

Media

  • In networking, it refers to the physical materials used to transmit data (e.g. copper cable, fibre optic cable, wireless signals)

Wide Area Network (WAN) Links

  • Used to connect networks over large geographical areas, using lease lines, satellite communications or cellular networks

Understanding network components is crucial in the field of information technology

Network Resources

  • Data moved around network by two main models - Client/Server Model and Peer-to-Peer Model

Client/Server Model

  • Utilises a dedicated server to provide access to network resources (files, scanners, printers, etc.)

  • Admin and backup are easier - one central machine that resources are on - can configure machine and accesses

  • Main choice in business networks

  • Benefits -
    - Centralised administration - one or two main servers to focus on
    - Easier management - same reason as above
    - Better Scalability - can expand outwards using cloud architecture/ additional servers

  • Drawbacks -
    - Costs more money - requires dedicated hardware
    - Requires dedicated OS - Windows, Linux etc.
    - Requires specialised skill set

Peer-to-Peer Model

  • Peers or other machines (e.g. laptops, desktops etc.) can share resources together directly.

  • Admin and backup very difficult due to files being located on different machines in different places

  • Benefits -
    - Lower cost - No hardware, no infrastructure, just software to enable users to share files
    - No specialised operating system
    - No dedicated resources

  • Drawbacks -
    - decentralised management -
    - inefficient for large networks - e.g business networks
    - poor scalability

Network Geography

Personal Area Network (PAN)

  • Smallest type of wired or wireless network which usually covers a distance of about 10 feet or less

  • E.G - Bluetooth, USB

Local Area Network (LAN)

  • Connects components in a limited distance up to about 100 metres.

  • E.G - Office, home, school

  • Network can consist of Wi-Fi or Ethernet

  • Ethernet - uses IEE 802.3 standard

  • Wi-Fi - uses IEE 802.11 standard

Campus Area Network (CAN)

  • A building-centric LAN that is spread across numerous buildings in a certain area.

  • Can cross several miles across many different buildings

  • Each building has a LAN which are then connected

  • E.G - University./college campuses, business parks, military bases

Metropolitan Area Network (MAN)

  • Connects locations that are spread across the entire city

  • Can cover upto around 25 miles or so

  • Often CAN/LAN connected together to form this

  • E.G. - Multiple campus universities, police departments with stations across the city

Wide Area Network (WAN)

  • connects geographically disparate internal networks

  • consists on Lease Lines or Virtual Private Networks

  • covers a large geographical area - country/world

  • e.g. - internet!

  • Doesn’t always have to be public - Government networks are private

  • Network geography is about distance involved