This is a 64-bit counter, accumulated since the last reboot, of connections that were attempted but declined because the firewall did not have the resources available to set them up. An admin checks this counter to tell whether connection failures are caused by capacity limits (like exhausted connection-table memory) rather than security policy. For example, a firewall under a connection flood might show this counter climbing rapidly while cufwConnGlobalNumPolicyDeclined stays flat, pointing the admin toward a resource-sizing or DoS-mitigation problem instead of an ACL issue.