A Wide Area Network (WAN) is a computer network that covers a wide geographic area. The term WAN is often used in contrast to a Local Area Network (LAN). A WAN aggregates multiple LANs, which are usually connected via public networks such as the telephone system or the Internet.

WANs can be used to connect geographically dispersed sites, such as branch offices and remote data centers. WANs can also be used to connect individual users to centralized resources, such as cloud-based applications.

WAN aggregation is a technique for combining multiple WAN links into a single logical link. WAN aggregation can be used to increase the bandwidth of a WAN connection or to provide redundancy in the event of a link failure.

WAN aggregation is typically implemented using a router with multiple WAN ports. The router will distribute traffic across the WAN links according to a configured policy. For example, the router may use a round-robin approach to distribute traffic equally across all links.

WAN aggregation is sometimes referred to as WAN bonding, WAN link aggregation, or WAN trunking.

WAN optimization is a technique for improving the performance of a WAN connection. WAN optimization can be used to reduce the amount of bandwidth required for a given workload or to improve the response time for applications that are sensitive to latency.

WAN optimization is typically implemented using a combination of hardware and software. Hardware-based WAN optimizers are typically deployed at key points in the network, such as at the edge of the network and at aggregation points. Software-based WAN optimizers are typically deployed on servers or workstations.

WAN optimization is sometimes referred to as WAN acceleration, WAN compression, or WAN caching.

WAN virtualization is a technique for creating multiple virtual WANs on a single physical WAN. WAN virtualization can be used to segment a WAN into multiple logical networks, or to provide redundant connectivity in the event of a link failure.

WAN virtualization is typically implemented using a router with multiple WAN ports. The router will create virtual WANs by multiplexing traffic across the physical WAN links.

WAN virtualization is sometimes referred to as WAN partitioning, WAN segmentation, or WAN redundancy.