Importance of Networks

Networks are critical to modern society, driving business decisions, product development, customer research, and more.
3,000 petabytes of information are transferred over the internet every day (Cisco, 2016).
Netflix accounted for a third of prime-time downstream traffic in 2013.
Amazon sold an average of 426 items every second during the holiday season.
Facebook had 2.7 billion likes, 300 million uploaded photos, and 500 terabytes of data daily in 2012.

Data communications involve the movement of computer information from one point to another using electronic or optical transmission systems.
Telecommunications networks, designed for voice and video, can also be used to move data across greater distances.

Clients: devices used to connect to a network and receive data from a server (e.g., desktops, laptops, smartphones, smart thermostats, alarm systems).
Servers: devices that transmit data to clients (e.g., web servers, mail servers, file servers).
Circuits: pathways between clients and servers (physical connections like copper wires or fiber optic cables, or wireless connections like radio signals or infrared signals).

Local Area Network (LAN): a small network containing a single room, floor, or building, often using wireless circuits.
Backbone Network: a high-speed network connecting multiple LANs, typically spanning hundreds of feet to several miles.
Wide Area Network (WAN): connects LANs and backbone networks across greater distances, often leasing circuits from telecommunication companies.

Internet Model (TCP/IP): the most common network model used today, also called the Internet Protocol Suite.
OSI Model: a more detailed model with seven layers, where the Internet Model simplifies the process.

Application Layer: includes presentation and session layers, focusing on the purpose and functionality of data transfer.
Transport and Network Layers: move information across the network, with the Internet Model simplifying these layers.
Data Link Layer: decides how to encode data for transmission.
Physical Layer: converts data into electronic or light signals.

Rules governing data transfer in each layer, with protocol data units (PDU) added at each layer.
Example: requesting a website involves adding PDUs at the application, transport, network, and hardware layers.

Formal standards: formalized by organizations like IEEE (e.g., HTTP protocol, wired and wireless protocols).
De facto standards: widely accepted, but not formalized (e.g., Microsoft Windows operating system).

Bring Your Own Device (BYOD): employees connecting personal devices to organizational networks, raising security and support concerns.
Internet of Things (IoT): connecting devices to the internet, increasing network demand and security risks.
Massively Online Platforms: online environments supporting millions of users, requiring more network infrastructure.

Networks are critical to modern society, driving business decisions, product development, customer research, and more.
3,000 petabytes of information are transferred over the internet every day (Cisco, 2016).
Netflix accounted for a third of prime-time downstream traffic in 2013.
Amazon sold an average of 426 items every second during the holiday season.
Facebook had 2.7 billion likes, 300 million uploaded photos, and 500 terabytes of data daily in 2012.

Data communications involve the movement of computer information from one point to another using electronic or optical transmission systems.
Telecommunications networks, designed for voice and video, can also be used to move data across greater distances.

Clients are devices used to connect to a network and receive data from a server, examples include desktops, laptops, smartphones, smart thermostats, and alarm systems.
Servers are devices that transmit data to clients, examples include web servers, mail servers, and file servers.
Circuits are pathways between clients and servers, including physical connections like copper wires or fiber optic cables, or wireless connections like radio signals or infrared signals.

Local Area Network (LAN) is a small network containing a single room, floor, or building, often using wireless circuits.
Backbone Network is a high-speed network connecting multiple LANs, typically spanning hundreds of feet to several miles.
Wide Area Network (WAN) connects LANs and backbone networks across greater distances, often leasing circuits from telecommunication companies.

Internet Model (TCP/IP) is the most common network model used today, also called the Internet Protocol Suite.
OSI Model is a more detailed model with seven layers, where the Internet Model simplifies the process.

Application Layer includes presentation and session layers, focusing on the purpose and functionality of data transfer.
Transport and Network Layers move information across the network, with the Internet Model simplifying these layers.
Data Link Layer decides how to encode data for transmission.
Physical Layer converts data into electronic or light signals.

Protocols are rules governing data transfer in each layer, with protocol data units (PDU) added at each layer.
Example: requesting a website involves adding PDUs at the application, transport, network, and hardware layers.

Formal standards are formalized by organizations like IEEE, examples include HTTP protocol, wired and wireless protocols.
De facto standards are widely accepted, but not formalized, examples include Microsoft Windows operating system.

Bring Your Own Device (BYOD) is a trend where employees connect personal devices to organizational networks, raising security and support concerns.
Internet of Things (IoT) connects devices to the internet, increasing network demand and security risks.
Massively Online Platforms are online environments supporting millions of users, requiring more network infrastructure.