Manage Broadcast Traffic With a WINS Server

Enabling a WINS server on your network can reduce broadcast traffic. With dozens or even hundreds of computers, WINS converts the NetBIOS name to an IP address. Computers that use NetBIOS over TCP/IP or NBT communicate with the WINS server to find other computers on a network. This in turn allows computers to communicate without broadcast the 'name' of the computer across the entire network. Working with DHCP, the WINS server's IP address is given to all computers that boot up and request an IP address from the DHCP server.

The registration and release of NBT is sent to the WINS server rather than being broadcast across the network. Therefore a computer will look for the WINS server first, report in and then use the IP address to get to where it is going.

The Five NBT Name Resolution Methods are:

• B-node - broadcast - This uses UDP broadcast datagrams. This is the default node type.

• Microsoft enhanced B-node - Checks address cache which is loaded from the lmhosts file (C:\windows\system32\drivers\etc) when the system boots. This is used by checking the lmhost file and if the NetBIOS name and IP address are not found in the file, WINS is used

• H-node - Hybrid - Tries P-node then B-node resolution.

• M-node - Mixed - Tries B-node then P-node resolution.

• P-node - Peer to peer - Uses a NetBIOS name server such as WINS.

There is a NetBIOS name for each service a computer offers. This uses the 16th hidden character of the NetBIOS names. The meaning of the characters are:

• 00 - Workstation service

• 03 - Messenger service

• 06 - RAS server service

• 1B - Primary domain controller

• 1C - Domain controller or PDC or BDC

• 1D - Master browser

• 1E - Servers

• 1F - NetDDE service

• 20 - Server service

• 21 - RAS client

• BE - Network Monitoring Agent service

• BF - Network monitor utility service

When WINS is used, computers report in to the WINS server so that a database can be built. (This database contains the NetBIOS names of the computers mapped out to the IP address of the computers.)

WINS Message Modes:

• Client Name Registration Information that is sent to the WINS Server

• Client Lease Renewal - Like DHCP, WINS leases time to the computers. When the name lease is at 50%, the client sends a name renewal request to the WINS server.

• Client Name Release - The client sends a name release message with its name and IP address. .

• Server Name Query and Name Resolution response - (See the resolution information above.) With a WINS server on your network, resolution uses H-node on UDP port 137 first.

How is this information queried?

1. Local cache

2. WINS server

3. Broadcast

4. Lmhosts file (found under the path found above)

The WINS software is provided from within the Microsoft server operating systems as a component. Installation is fast and easy and requires very little maintenance. WINS offers an option to replicate providing redundancy with another WINS server on your network.

A WINS server can help hold down broadcast traffic on networks when there are multiple computers on your network. This server has a static IP address that is configured in the DHCP server configuration. This service allows computers to pick up this IP address and report to the WINS server instead of broadcasting across the network. Reducing broadcast allows for less congestion on these larger enterprise networks. With more and more computers, printers, access points and nodes on a network, networks can become very busy with broadcast traffic. The lack of a WINS server can reduce the overall performance of your network.