This counts the number of times a TCP connection underlying this FCIP link was closed down due to a security association parameter mismatch -- typically an IPsec-related configuration inconsistency between the two ends. This is the counter to check first when an FCIP link protected by IPsec keeps failing to establish or repeatedly drops, since it isolates the problem to security-parameter negotiation rather than any of the more general connectivity or congestion causes tracked by the other TCP closure counters. An FCIP link recently configured to use IPsec encryption that now will not stay up, with this counter climbing each time, points an admin directly at reconciling the IKE/IPsec transform sets or pre-shared keys configured on each end rather than investigating bandwidth or latency.