A local area network usually co-locates hosts across a small geographic area, e.g., one or more buildings; primarily uses Layer 2 devices; and is owned and controlled by a single person or company. A wide area network is usually spread across a large geographic area, one that crosses metropolitan, regional, or national borders; uses more Layer 3 devices; and is often connected via public networks. In general, when creating paths, choose LAN if the path source and path target are in the same building, and choose WAN if the path between the source and target will cross a public network.
APM checks LAN/WAN path designations nightly. They are defined as follows:
LAN path - < 4 hops (including the target) or latency < 5ms.
WAN path - >= 4 hops (including the target) and latency >= 5ms.
The path designation will automatically be changed to WAN if it doesn’t meet the criteria for LAN; paths will not be changed from WAN to LAN if the WAN criteria is not met. To be clear, once the nightly check changes a LAN path to WAN, it will never be changed back, even if the path currently meets the LAN requirements.