What are LAN, WAN, and SD-WAN?

What do LAN, WAN, and SD-WAN mean?

WAN and LAN are terms for the network of communication connectivity that is either TO a building or INSIDE a building.

WAN = Wide Area Network (outside to the router)

LAN = Local Area Network (router to everything inside)

LAN is essentially all the interconnected devices INSIDE, and WAN refers to everything OUTSIDE the walls.

A LAN is typically set up with a router connected to the MPOE (Minimum Point of Entry) that connects out to the network. An Ethernet switch with devices like computers and phones plugged into it is connected to the router in the LAN. LAN makes it possible for you to have a connection between all your devices, such as phones, computers, and tablets to the outside world.

If we are talking about a business situation where there are multiple locations, for example: a main headquarters and two satellite office locations, then information is exchanged between the locations via WAN.

An example of WAN technology that is used is VPN (Virtual Private Network). VPN is like a private tunnel for information piggybacked onto the public internet, where only certain people or devices are granted access. It leverages the internet and acts as a replacement for a traditional private WAN. VPN is commonly used for remote access to a company’s internal information, such as their customer files and records, so that this information could become safely available to an approved worker when offsite.


Software-defined WAN (SD-WAN) uses software-defined networking (SDN) to determine the most effective way to route traffic to remote locations in an enterprise setting. This boils down to software programs that act as intersection stoplights, routing traffic in the most efficient direction possible. Without this programmed routing, voice, data and other information can get bogged down when all trying to pass over the same internet connection.

SD-WAN uses multiple tunnels to optimize bandwidth by directing WAN traffic along the best route to and from offices and data center sites. SD-WAN technology centralizes network control and enables agile, real-time traffic management over these links. There are a variety of SD-WAN products and services, but most fall into the categories of overlay SD-WAN or network as a service.

Since SD-WAN is managed by a centralized controller, IT staff are able to remotely program devices and thus reduce provisioning times and the need to manually configure routers at multiple locations.


While you may not need to use these terms in your everyday conversation, their function effects your daily life both at home, at work, and in public. Connectivity for retrieving or sharing information via voice, text, email, online banking, transaction processing, etc.. is essential. So, whether you are checking the balance of your bank account, making an online purchase, or logging into work remotely, these technologies are at play.

When it comes to business operations, it is important to know what your options are for speed, security, and quality of service.

This is a rapidly changing environment; and there have been significant developments in this technology. Not too long ago a technology called Frame Relay was the dominant WAN technology, but Frame Relay was replaced with a faster, smarter service called MPLS, or Multi Protocol Label Switching. MPLS provides guaranteed performance with quality of service (QoS) policies that govern throughput, delay and jitter; all threats to the quality of your downloads, uploads, and voice over internet (VoIP) phone calls. Since MPLS can be expensive and time consuming to implement, some organizations are utilizing SD-WAN and increased internet bandwidth to increase their security and agility. While these abilities used to only make sense for enterprise-size companies, now there are options available even for smaller companies to utilize SD-WAN capabilities as a service. This enables them to maximize their bandwidth and improve the security of their information at a reasonable cost.

Due to the ever changing market and improvements in availability, it is important to enlist an industry specialist that can find the right solution for your company’s needs. Click below to have an experienced consultant research what’s available in your area, and what options would make the most sense for your needs.