WINS replication overview
Updated: January 21, 2005
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2, Windows Server 2008, Windows Server 2008 R2, Windows Server 8 Beta
Where multiple WINS servers are used on your network, they can be configured to replicate records in their databases to other servers. This process is shown in the following figure. Two WINS servers, WINS-A and WINS-B, are both configured to fully replicate their records with each other.
By using replication between these WINS servers, a consistent set of WINS information is maintained and distributed throughout the network. For example, in the previous figure a WINS client (HOST-1) on Subnet 1 registers its name with its primary WINS server, WINS-A. Another WINS client (HOST-2) on Subnet 3 registers its name with its primary WINS server, WINS-B. If either of these hosts later attempts to locate the other host using WINS--for example, HOST-1 queries to find an IP address for HOST-2--replication between the WINS servers (WINS-A and WINS-B) makes resolving this query possible.
For replication to work, each WINS server must be configured with at least one other WINS server as its replication partner. This ensures that a name registered with one WINS server is eventually replicated to all other WINS servers in the network. A replication partner can be added and configured as either a pull partner, a push partner or to use both types of replication as a push/pull partner. The push/pull partner type is the default configuration and is the type recommended for use in most cases.
When WINS servers replicate, a latency period exists before a client name-to-address mapping from any given server is propagated to all other WINS servers in the network. This latency is known as the convergence time for the entire WINS system. For example, a name release request by a client will not propagate as fast as a name registration request. This is intended by design because it is common for client names to be released and then reused with the same mapping as computers are restarted or periodically shut down. Replicating each of these name releases would unnecessarily increase the network load of replication.
Also, when a WINS client computer is shut down improperly, as in the case of an unexpected power outage, the registered names of the computer are not released as they normally would be by sending a name release request to the WINS server. Therefore, the presence of a name-to-address record in the WINS database does not necessarily mean that a client computer is still using the name or its associated IP address. It only means that at some recent time in the past, a computer by the registered name claimed the mapped IP address for its use.
The primary and secondary WINS servers of any client should typically have a push and pull relationship with each other. However, a direct push/pull configuration is not required as long as similar results can be indirectly achieved during a normal replication cycle.
WINS replication is always incremental, meaning that only changes in the database are replicated each time replication occurs, not the entire database.