High Availability Licensing (HAL) allows you to specify backup (redundant) license servers that will continue to enable license hosting in the event that the primary license server goes down. To use HAL, your license must be HAL-enabled by your vendor. See Enabling and configuring HAL for information about using the web-based UI to set up HAL license servers.
HAL requires a stable network connection to prevent hiccups in traffic between the servers, which can potentially cause license checkout problems. Too many network problems will make the system unstable and users will not get reliable access to the software. For this reason, enabling HAL over WAN is recommended only if the connection is fast and stable.
Note that a license server can serve either a HAL-enabled license or normal network license, not both.