Windows Internet Name Service

How WINS Clients Release Their Names

NetBIOS names can be released either explicitly or silently. They are explicitly released when a client shuts down gracefully. A silent release occurs when an client fails or is powered off. The silent release is noted at the WINS server when a name is not refreshed within the renewal interval.

When a name is released, the database entry is marked as released and given a time stamp with the current time plus the extinction interval. The extinction interval is the interval between when an entry is marked as released and when it is marked as extinct. The extinction timeout specifies the interval between when an entry is marked extinct and when the entry is finally scavenged from the database. This information is not propagated to partner WINS servers. If the release is explicit, the WINS server makes itself the owner of the record if it is not already.

In Windows 2000, the release of a WINS database entry is handled differently if the owner ID of the entry is different from the owner ID of the server that registered the name. If this is the case, the entry is marked as extinct and given a time stamp that is the current time plus the sum of the extinction interval and the extinction timeout. This is done to avoid windows of inconsistency between secondary and primary WINS servers. Because a released record is not replicated again, having already been replicated once, its name remains released on one WINS server and active on another for undesirably long periods.

Changing the released record to the extinct state results in its replication and enables rapid synchronization of WINS databases. Without extinction, inconsistencies might linger. For example, if the primary WINS server of a client is unavailable when the client shuts down, the name release would be directed to the secondary WINS server. If the primary WINS server is available again when the client restarts, the client would register and continue to refresh with the primary WINS server, which has not recorded any change in the status of the client, while the secondary WINS server would still reflect the released state of the client record.