This Counter32, keyed by the ATM link index, counts F5 flow segment-level OAM cells — the standard ITU-T ATM virtual-channel-level operations/maintenance cells exchanged between adjacent segment endpoints — with the source DESCRIPTION left blank so the meaning follows the standard ATM F5 OAM flow implied by the object name. Admins use this to confirm VC-level segment OAM continuity checking is active on this link, complementing the VP-level F4 counters elsewhere in this table. For example, a technician verifying VC-level fault management on a specific PVC would check this counter for evidence that F5 segment OAM cells are being processed.