What's the Difference between a LAN & a WAN?
Most computer users are familiar with the concept of a Local Area Network (LAN). A Wide Area Network is perhaps less familiar, but its function is essentially the same. Both types of network allow computer users to collaborate and communicate using voice, video or data.
A LAN consists of a group of computers that are physically close and interconnected by high-speed cable or wireless links.
The big disadvantage of a LAN is that it is restricted to a single site, such as an office, a school or a single home.
A Wide Area Network (WAN), as its name suggests, allows much greater numbers of users in a much bigger geographical area to communicate and collaborate.
A LAN is used to link individual computers in an office using Ethernet cabling or wireless links. The infrastructure needed to create a LAN is typically owned by the business, school or home that uses it.
As well as Ethernet cabling, LAN infrastructure includes communications devices such as routers, switches and WiFi access points.
By contrast, WANs do not usually link individual computers, but are used to link LANs. Another important difference is that the users of a WAN usually do not own the infrastructure that links their LANs in different locations. Instead the inter-LAN connectivity is provided by one or more telecommunications companies.
WANs have historically transmitted data at much slower speeds than LANs, but recent advances in WAN technology mean that businesses that sign up for a WAN service can now communicate at the same high speeds between offices as their users experience within an office.
A LAN based on the Ethernet standard allows users within a single office network to communicate at speeds of 10 megabit/s, 100 megabit/s or 1 gigabit/s, depending on the variant of Ethernet technology used.
Advances in WAN networking technology allow communications service providers to offer connection speeds in the core of a WAN that range from 1 Gbit/s to 100 Gbit/s.
That core bandwidth is typically shared between several corporate customers, so the bandwidth available at the edge of the WAN to an individual business can range from 1 megabit/s to 10 gigabit/s.
Another area where historically there have been big differences between LANs and WANs is in service quality.
Assuming a LAN is configured and installed correctly, it should be very reliable and give very problems as the devices that make up the network are relatively simple and the traffic on the LAN is likely to be predictable.
With a WAN, however, the underlying infrastructure is much more complex and distributed across a much wider geographic area. Network traffic is more difficult to predict and manage on a WAN.
Businesses can either manage the WAN themselves or they can let the service provider take care of issues such as detecting faults, minimising congestion and ensuring optimum service levels.
If a business wants to run mission-critical applications, it should choose a provider that owns the underlying WAN infrastructure as that way the service provider can offer a true end-to-end service level agreement (SLA) and ensure maximum performance and uptime.