Module 1: Communications in a Connected World

Network Types

The internet is not owned by any individual or group. The internet is a worldwide collection of interconnected networks (internetwork or internet for short), cooperating with each other to exchange information using common standards. Through telephone wires, fiber-optic cables, wireless transmissions, and satellite links, internet users can exchange information in a variety of forms.

Small home networks connect a few computers to each other and to the internet. The SOHO network allows computers in a home office or a remote office to connect to a corporate network, or access centralized, shared resources. Medium to large networks, such as those used by corporations and schools, can have many locations with hundreds or thousands of interconnected hosts. The internet is a network of networks that connects hundreds of millions of computers world-wide.

There are devices all around that you may interact with on a daily basis that are also connected to the internet. These include mobile devices such as smartphones, tablets, smartwatches, and smart glasses. Things in your home can be connected to the internet such as a security system, appliances, your smart TV, and your gaming console. Outside your home there are smart cars, RFID tags, sensors and actuators, and even medical devices which can be connected.

Data Transmission

The following categories are used to classify types of personal data:

• Volunteered data - This is created and explicitly shared by individuals, such as social network profiles. This type of data might include video files, pictures, text, or audio files.
• Observed data - This is captured by recording the actions of individuals, such as location data when using cell phones.
• Inferred data - This is data such as a credit score, which is based on analysis of volunteered or observed data.

The term bit is an abbreviation of “binary digit” and represents the smallest piece of data. Each bit can only have one of two possible values, 0 or 1.

There are three common methods of signal transmission used in networks:

• Electrical signals - Transmission is achieved by representing data as electrical pulses on copper wire.
• Optical signals - Transmission is achieved by converting the electrical signals into light pulses.
• Wireless signals - Transmission is achieved by using infrared, microwave, or radio waves through the air.

Bandwidth and Throughput

Bandwidth is the capacity of a medium to carry data. Digital bandwidth measures the amount of data that can flow from one place to another in a given amount of time. Bandwidth is typically measured in the number of bits that (theoretically) can be sent across the media in a second. Common bandwidth measurements are as follows:

• Thousands of bits per second (Kbps)
• Millions of bits per second (Mbps)
• Billions of bits per second (Gbps)

Throughput does not usually match the specified bandwidth. Many factors influence throughput including:

• The amount of data being sent and received over the connection
• The latency created by the number of network devices encountered between source and destination

Latency refers to the amount of time, including delays, for data to travel from one given point to another.