Understanding network sizes – SOHO, LAN, and WAN

Let's imagine we have a few devices that are all interconnected in a single network, sharing files between themselves without having the user (human) physically walk around with a portable storage device such as a flash drive to copy and paste files. Users access a centralized file server within the company's network from their local computer.

The following diagram shows a small network with both a network-shared printer and file server:

Figure 1.1 – Devices interconnected to create a small LAN

This type of network is commonly referred to as a LAN. A LAN is defined as a small computer network that does not exceed the physical space of a home or a single building. To help you understand this, we're going to use a simple analogy. Let's imagine you work for ACME, a fictional-based organization that has a single branch. Within the branch (that is, the physical building), ACME has a LAN that is used to interconnect all their devices – computers, servers, printers, and so on. This LAN allows employees to sit at their workstations and send documents to print via the network to the local printer and access the file server to store and copy files for their projects. Let's call this office location HQ.

The following diagram shows a typical LAN with interconnected devices within the HQ building:

Figure 1.2 – A building containing a LAN

One day, ACME wants to open a new branch in another city to provide services to new and potential customers; however, there is a challenge. We shall refer to the new branch as BranchA. The new location, BranchA, is many miles away and the staff at BranchA need to access resources such as the application server, Customer Relationship Management (CRM) database, and other important resources that are located at the HQ location. One solution would be to create a clone of the servers from HQ to the new location, BranchA; however, this means each time new records and data is updated at the HQ location, it will take a long time to replicate the data on the servers at BranchA. This may create inconsistency issues when employees try to access the most up-to-date files and records at BranchA.

Important note

In our scenario, BranchA is typically known as a Small Office/Home Office (SOHO). This type of network is generally smaller than the main corporate office of a company, but it enables the users to connect or access the resources that are centrally shared on the corporate network (HQ).

A better approach is to create a WAN. A WAN is used to simply extend a LAN over a large geographic distance. A company such as ACME would definitely benefit from using this technology within their organization. By implementing a WAN between their branches, HQ and BranchA, the servers and main resources can simply stay at HQ while employees are still able to access the resources, files, and records across the network at their BranchA location.

The following diagram shows a depiction of a WAN connection between the HQ location and the new branch office:

Figure 1.3 – A WAN connection between two buildings

In modern times, WANs are managed by service providers (SP) and Internet Service Providers (ISPs). WANs can extend your LAN beyond cities, countries, and even continents. ISPs offer a range of WAN services to their customers, such as the following:

• Metro Ethernet (MetroE)
• Virtual Private LAN Service (VPLS)
• Multiprotocol Label Switching (MPLS)

As a simple example, MetroE enables customers of a service provider to establish a WAN between branches, functioning like a very huge LAN within the service provider network. This means a company can interconnect multiple branches using a MetroE service within the service provider network. On the customer's end, the network functions as if it were on a large LAN.

Another type of WAN service is MPLS, which provides us with the functionality to extend an organization's network beyond the local service provider's network. Imagine having a WAN circuit starting from the HQ location and passing through multiple ISP networks until the connection is terminated at a remote branch in another country.

With that, we have covered the fundamentals of SOHOs, LANs, and WANs. In the next section, we will learn about the components that help us build and extend networks.