What is a Network? Network is the base term used to represent the connectivity between devices that need to share a resource such as data, printer, or internet access. When referring to a network you will generally either refer to the LAN or the WAN. Local Area Network (LAN) is the connection in a single location between computers where a Wide Are Network (WAN) refers to the connectivity between disparate locations that leverage a service providers network to connect. There is a hybrid network type referred to as a Metropolitan Area Network (MAN) which is really a larger version of a LAN because it extends across a larger geographic area, like a city, but typically traverses private connections like Fiber. Virtual Private Network (VPN) is the extension of an internal network across a public network using either a software client or hardware. WAN is all the rage today with the all the talk around Software Defined Wide Area Network (SD-WAN) of which we will talk about more in a future post. There are many ways to connect to a WAN, but other than Point to Point (P2P) and MAN, WAN connectivity relies on a service provider that may be wired or wireless, and may be based on access to the internet or access to a private network built and managed by the service provider. WAN Connection Types: Connection to a WAN typically requires connection to a service provider network as referenced above but there are multiple ways to do this. The first and most cost effective method is generally with a Dedicated Internet Access (DIA) connection type like your home internet. You will generally hear these connection mediums referred to as Broadband, LTE, DSL, Cable, or Fiber. The important thing to understand, is these connections are just to the public internet and depending on the connection type they generally do not include security, prioritization of the traffic, or guaranteed upload and download speeds. They are typically the most cost-effective method of connectivity and include the largest advertised bandwidth availability. Since most larger organizations require security, reliability, and traffic prioritization (think limiting YouTube on your guest wireless over internal access to business applications) the service providers offer a type of private connection that comes at a much higher expense. This provides the benefits mentioned above and when the provider leverages something like Multi-Protocol Label Switching (MPLS), which is an overlay network that allows the provider to build a private network instance for the client that accepts connections from multiple providers, you also gain the benefit of a single provider for billing and problem resolution. One throat to choke and one bill to pay! As mentioned before, this does come at a higher price and generally at lower bandwidths. For Simplicity think of it this way: The devices in your home that connect to the internet are on your LAN which is the connection between your devices (wired or wireless) and the router provided by the service provider. When you set-up internet access for your home you called the local service provider and they provided you a connection (the medium depends on your availability but could be cable, dsl, fiber, wireless, satellite, etc). That connection is a DIA . When you need to access company resources that are not available via the public internet you likely connect with a VPN which would now place you on your companies WAN . When your company needs to provide connectivity to locations with multiple users and needs to ensure it is controllable, the bandwidth is dedicated, and the routing is secure, they would deploy a MPLS type connection to the location for WAN access. In a follow-up post we will dive a little deeper into SD-WAN. What it is, what problems it solves, and the different ways to consume it.