This read-write TruthValue enables or disables the ABR standard with VSVD (a specific ABR flow-control mechanism); the feature is enabled when the value is True. An administrator toggles this to control whether standards-based flow control governs ABR virtual circuits on the node, which affects how ABR connections respond to network congestion. For example, enabling this feature helps ABR traffic dynamically adjust its sending rate in response to congestion feedback rather than sending at a fixed rate regardless of trunk load.