This is a per-link on/off switch for FCIP tape acceleration, a feature specifically designed to improve tape backup write throughput over an FCIP (Fibre Channel over IP) link. Tape acceleration works by locally acknowledging certain SCSI write commands to hide the round-trip latency of a long-distance IP link from the tape drive, so enabling this on a WAN-spanning backup link can dramatically cut backup job time, but it should only be enabled on links actually carrying tape traffic since it changes acknowledgement behavior. A remote-office-to-datacenter FCIP link carrying nightly LTO tape backups across a 2,000-mile WAN would typically have this set to true specifically to offset the latency penalty that distance otherwise imposes on tape write performance.