If you’ve been around IT for even a few minutes, you’ve likely heard the acronyms “LAN” and “WAN” used by fellow technicians. But with all of the possible variations of networks-different sizes, different arrangements, and different protocols-how do you tell the difference between a LAN and a WAN and everything in between? The simple answer is one of scope and size.
In general, we tend to group networks into two categories: LAN (Local Area Network) and WAN (Wide Area Network). A LAN, by definition, is a smaller network that is located in a single geographic area under the management of a single domain, administrator or organization whereas a WAN is a larger network that connects networks across a larger distance. However, you may have heard someone refer to a single room of computers as a LAN. But what about a WLAN (Wireless LAN)? Is there a difference between a network that connects my sites across town and one that connects my site with other sites around the world?
LANs and WANs are broad categories that can be subdivided into smaller categories. Other characteristics that divide these two categories and help us classify the subcategories are who manages the infrastructure and what physical protocols are used. LANs are managed by local administrators and tend to rely on protocols like Ethernet, Wi-Fi or Token Ring (now obsolete). WANs rely on a completely different set of protocols. There are many WAN protocols, but some of the popular ones are MPLS, Frame Relay and Metro Ethernet (for businesses) and DSL, Cable and Fiber-to-the-Home (for consumers).
The smallest type of LAN is referred to as a PAN or Personal Area Network. Rather than having an administrator, a PAN is a group of personal devices owned by a single person. Most PANs rely on USB cables and Bluetooth wireless although an ad hoc Wi-Fi connection could also count as a PAN. Traditional PAN devices are smartphones, tablets, laptops and peripheral devices (like headsets and printers). Due to the widespread proliferation of IoT (Internet of Things), our PANs now include everyday household items like household appliances, cars and even lightbulbs.
When compared with other LAN subcategories, we use the term LAN to indicate networks that rely on Ethernet and Wi-Fi. This could range in size from a SOHO LAN (Small Office/Home Office), to a SME (Small to Medium size Enterprise), all the way to our largest enterprise LANs that may cover an entire skyscraper. But we’re still talking about one room, one floor or one building under the control of an administrator. Adding Wi-Fi turns a LAN into a WLAN.
Sometimes a LAN needs to connect networks from several buildings for businesses like schools, hospitals and office parks. This largest type of LAN relies on robust backbone networks (usually fiber optic cables) to allow these buildings to be controlled by a single LAN administrator. If the campus is in a single geographic location connected by Ethernet, it is a LAN. However, if the distance is great enough to make the cost of self-administered network cables more prohibitive, larger businesses rely on a new set of protocols managed by a service provider. This is where we cross from a LAN to a WAN. The Campus Area Network is the only type of network that can be either a LAN or a WAN depending on the protocols that are used to connect the various buildings.
As we continue to grow our network across a metropolitan area, we get a Metropolitan Area Network. Due to the distance between facilities, MANs require a local service provider, like a cable provider or telecommunications provider, to connect the various locations. MANs connect headquarters to branch offices, LANs to datacenters, warehouses to retail spaces.
The largest network of all is the Wide Area Network. This network category spans across states, across the country, across continents, and ultimately across the globe. Some WANs are private, used by business to connect sites that are located very far from each other. Some WANs are public, shared networks that allow anyone to participate. The largest WAN in the world is the Internet, connecting servers from business all around the world using specialized protocols, specialized equipment, and managed by specialized WAN administrators. At this point, you need a provider to connect these disparate networks. The cost to build your own WAN would be insurmountable and unrealistic.
Typically, when you attend a networking class, you learn all about the LAN and the many protocols that we use within the LAN. We may introduce you to the idea of a WAN but becoming a WAN expert is a separate career path. Most LAN administrators start their career with certifications like CompTIA Network+ or Cisco’s Certified Entry-Level Network Technician (CCENT).
Eventually, any network technician who wants to advance their career will need to complete the full Cisco Certified Network Administrator certification (CCNA). There are also specific wireless certifications you can achieve such as the CWNA (Certified Wireless Network Administrator). You may also consider other vendor specific technologies like Microsoft, HP, Juniper and more.