Introduction
Microsoft Windows Internet Name Service (WINS) has been enhanced for the release of Microsoft Windows 2000 Server. The result is an easier-to-manage and more robust solution for mapping NetBIOS names to IP addresses on Transmission Control Protocol/Internet Protocol (TCP/IP) networks.
Windows 2000 WINS includes server enhancements, additional client functions, and an improved management tool. WINS provides a distributed database for registering and querying dynamic computer name-to-IP address mapping in a routed network environment. This support for dynamic registering of NetBIOS computer names means that WINS can be used with Dynamic Host Configuration Protocol (DHCP) services to provide easy configuration and administration of Windows-based TCP/IP networks.
The WINS server solves the problems inherent in resolving NetBIOS names through IP broadcasts, and frees network administrators from the demands of updating static mapping files, such as LMHOST files. WINS, which is compliant with the NetBIOS Name Server (NBNS) RFCs (1001/1002), also automatically updates the WINS database when dynamic addressing through DHCP results in new IP addresses for computers that move between subnets. Neither the user nor the network administrator needs to make manual accommodations for such name resolutions.
The new implementation of WINS provides a number of features, including:
Persistent connections—This configurable feature allows each WINS server to maintain a persistent connection with one or more replication partners to eliminate the overhead of opening and terminating connections and to increase the speed of replication.
Manual tombstoning—Use of the Manual tombstoning feature marks a record for deletion so that the tombstone state for the record is replicated across all WINS servers, preventing an undeleted copy of the record on a different server database from being re-propagated.
Improved management tools—The WINS Manager is fully integrated with the Microsoft Management Console (MMC), providing a more user-friendly and powerful environment for viewing and managing WINS information.
Enhanced filtering and record searching—These functions help locate records of interest by showing only those that fit a specific criteria. This is particularly useful for analyzing very large WINS databases.
Dynamic record deletion and multi-select—Managing the WINS database is made easier with dynamic record deletion and multi-select. Dynamic and static records can be deleted, and the point-and-click interface makes it possible to delete files with non-alphanumeric characters that could not be handled from the command line.
Record verification and version number validation—Two tools are available for quickly checking the consistency between various WINS servers. The tests are done by comparing the IP addresses of a NetBIOS name query returned from different WINS servers or by examining owner address to version-number mapping tables.
Export function—The Export command can be used to place WINS data into a comma-delimited text file that can be imported into Microsoft Excel, reporting tools, scripting applications, and so on, for analysis and reporting.
Increased fault tolerance—Windows 2000 and Windows 98 allow a client to specify more than two WINS servers (up to a maximum of 12 addresses) per interface. The extra WINS server addresses are used only if the primary and secondary WINS servers fail to respond.
Dynamic re-registration—WINS clients can now re-register their NetBIOS name-to- IP address mapping without rebooting the server.
All of this combines to make Windows 2000 WINS a superior choice for NetBIOS name resolution. The new generation of WINS services are designed to make many network management tasks much easier for network managers.
WINS Functional Description
Please refer to the white paper “Microsoft Windows NT Server 4.0 Windows Internet Naming Service (WINS) Architecture and Capacity Planning” (available at http://www.microsoft.com/ntserver) for a detailed description of WINS elements and functions.
New features of Windows 2000 WINS
Windows 2000 WINS contains significant enhancements, many of which were suggested by network managers. The result is an even more powerful and easier-to-manage NetBIOS-to-IP address service. New features include:
Persistent connections
Manual tombstoning
Improved management tool
Enhanced filtering and record searching
Dynamic record deletion and multi-select
Record verification and version number validation
Export function
Increased fault tolerance
Dynamic re-registration
Persistent Connections
Windows 2000 WINS introduces persistent connections between WINS server replication partners. This is important because the WINS database is collectively managed by a set of WINS servers, each of which has a copy of the WINS database. To keep these copies consistent, servers replicate records among each other. Each WINS server is configured with a set of one or more replication partners. Each new computer added to or substituted on the network registers its name and IP address with a WINS server, which in turn propagates the new record to all other WINS servers in the enterprise. The result is that every server has the record pertaining to that new computer.
Earlier versions of WINS required a new connection to be established between the WINS servers whenever replication was to occur, each of which required a modest number of processor cycles.
Therefore, network managers would set their systems to accumulate a configurable number of records prior to having servers establish connection with replication partners. This caused a delay to be introduced in the updating of the entire database, perhaps as long as several minutes, which could cause windows of inconsistency with replication partners.
Windows 2000 WINS provides a configurable feature that allows a server to request a persistent connection with one or more replication partners, which eliminates the overhead of opening and terminating connections. Persistent connections increase the speed of replication because a server can immediately send records to its partners without incurring the cost of establishing temporary connections each time. This provides the opportunity for every record received be immediately updated across the network, making records more consistent. The bandwidth used by persistent connections is minimal because the connection is usually idle.
Figure 1. Windows 2000 WINS configured to Use persistent connection
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