Network Basics and Fundamentals

A network can be created to be accessed within a single room, a building, a city, a country or spanned across the entire globe. Based on how the above network types are accessed geographically, networks can be further classified as

Personal Area Network (PAN)

• It is the smallest and most basic type of network, a PAN is made up of a wireless modem,  computers, phones, printers, tablets, etc., within one building.

• Personal Area Networks are most commonly used in our houses and small offices  where there are  less devices (less than 10 devices) connected to the network and managed from a single device.

Local Area Network (LAN)

• LANs connect groups of computers, printers and scanners etc together across short distances generally within one or two buildings to share information and resources.

• Enterprises typically manage and maintain LANs by themselves as they are dedicated to one or two organizations.

• These are the most common and widely created networks which we regularly use in offices.

Wireless Local Area Network (WLAN)

• Similar to LAN, WLANs make use of wireless network technology, such as WiFi.

• This type of networks are seen in the offices to access the LAN network wirelessly.

• This type of networks don’t require the devices to rely on physical cables to connect to the network.

Campus Area Network (CAN)

• Larger than LANs, but smaller than metropolitan area networks (MANs), these types of networks are typically seen in universities, colleges & small businesses.

• This type of network is generally spread across number of buildings which are close to each other so that users can share the information across the network.

Metropolitan Area Network (MAN)

• These types of networks are larger than LANs but smaller than WANs and they incorporate concepts from both types of networks.

• MAN network covers the entire geographic area, generally a town or city.

• Ownership and maintenance is handled by either a single person or an local organization.

Wide Area Network (WAN)

• This is more complex and larger than Local Area Network (LAN), Wide Area Network (WAN) is created to connect computers & mobile devices together which are spread across longer distances.

• This allows the devices in the WAN network to be remotely connected to each other over one large network even when they’re miles apart.

• The Internet is the best example of a WAN, connecting all computers & mobile devices together around the globe.

• WAN networks are generally owned and managed by multiple owners across the globe with similar standards because the network spans across countries.

Storage Area Network (SAN)

• This is a dedicated high-speed network that connects storage devices to multiple servers in a network. Data is shared across the SAN network via high-performance network.

• Storage through SAN network can be accessed from the server just as a drive attached to a server locally.

• Different types of Storage Area Networks can be created based on the use case such as converged, virtual and unified SANs. 

Virtual Private Network (VPN)

• This type of network is created by extending a private Local Area network (LAN) across the Internet. This type of networks are also referred as Virtual Private Cloud Network (VPC) in Cloud computing.

• This is the virtual network which can be an extension to the existing LAN network or an isolated network, generally seen in Cloud deployments. 

• VPN or VPC allows users to send and receive data remotely as if their devices were connected to the private LAN. 

See:  What is Software Defined Networking

Public vs Private vs External Networks

Based on how the network is created to access the public internet, networks can also be classified as follows

Internet

• The Internet is the public network where the devices (computers & mobile devices) can access the Internet network across many countries to exchange the information.

• This kind of networks uses Wide Area Network and are managed by multiple organizations and they follow similar standards.

• Since it is a public network, configuring security is the important consideration to prevent unauthorized access to the data that is transmitted through this network.

Intranet

• This is a private or internal network which is generally used inside an organization which is allowed to access by the employees or trusted vendors.

• Applications can be deployed and delivered internally which can be accessed via browsers internally within the company.

• Using these applications and having the employees access the information over a common browser saves time, money and prevent security threats if accessed over public internet.

• Cloud networks such as VPC and VPNs can be used to connect to the internal network allowing the access to the applications that are deployed in cloud.

• Coud services such as Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS) can also utilize internal networks to deploy the applications internally.

Extranet

• The extranet is also an intranet but the difference is that this network can be extended to business partners and a external partners.

• A company can develop internal applications to share with an external business partners and provide access to the applications via internal network instead of going through public internet.