Table Of Contents
Changing Server Bandwidth Parameter Settings
Changing Server Bandwidth Parameter Settings
This appendix describes how to change the default server bandwidth parameter settings. If you accept the server settings shown in Table B-1, you do not need to make any changes. However, you can change these settings by editing the Windows 2000 registry.
Base your decision of whether or not to change the default bandwidth parameters on the peak number of users that you expect to be using the BBSM server at the same time. However, keep in mind that BBSM continues to operate correctly even if the maximum number of users is exceeded occasionally and performance is degraded.
Note 
You can only make these changes locally and not from a remote server.
Caution Incorrect registry settings can render your BBSM server unusable. Alter only the parameters listed in
Table B-1. Always backup the registry before making any changes.
Table B-1 BBSM Bandwidth Management Configurable Parameters
Parameter
|
Description
|
BWTQueueSize
|
Amount of data per link to queue before discarding. The default should be adequate for TCP clients. For UDP clients (streaming audio or video), you must select a transmission rate below the bandwidth limit to avoid losing packets because of queue overflow. The default number of bytes is 151,400.
|
PacketPoolSize
|
The number of packet descriptors. The default is 50.
|
LookaheadPoolSize
|
The number of look-ahead buffer descriptors, which the packet descriptor indicates. Set the PacketPoolSize and LookaheadPoolSize parameters to a higher number than the anticipated maximum number of packets queued for bandwidth management. The default is 50.
•For TCP clients, this number is the TCP window divided by the packet size. For example, a typical Windows TCP client uses a window of 8192 bytes, and an Ethernet interface has a maximum packet size of 1514 bytes. Divide the window size (8192 bytes) by the packet size (1514 bytes) to allocate 6 packets per TCP client.
•For UDP clients, this number is the BTWQueueSize parameter value divided by the packet size. Calculate both and select the larger of the two values. For example, assume that the BWTQueueSize value is 15140 KB. Because the Ethernet packet size is 1514 bytes, divide 15140 by 1514 bytes to establish 10 packets per client. Because 10 is greater than 6, 10 packets per client would be used.
|
Follow this procedure to change the registry settings.
Step 1 Choose Start > Run. The Run window appears.
Step 2 Enter regedit and click OK. The Registry Editor window appears.
Step 3 Double-click HKEY_LOCAL_MACHINE.
Step 4 Navigate to System > CurrentControlSet > Services > ATNAT > Parameters.
Step 5 Right-click anywhere in the right pane of the Registry Editor window.
Step 6 To back up the file before making any changes, choose Registry > Export Registry File and follow the instructions.
Step 7 From the New drop-down menu, select DWORD Value.
Step 8 Rename the entry to the parameter name you want to change. For applicable parameter names, see Table B-1.
Step 9 Double-click the new parameter name. (See Figure B-1. Note that BTWQueueSize is shown here only as an example.)
Figure B-1 New Parameter Name
The Edit DWORD Value dialog box appears. (See Figure B-2.)
Figure B-2 Edit DWORD Value Dialog Box
Step 10 Click Decimal.
Step 11 In the Value data field, enter the new value in the appropriate units for that parameter name and then click OK. See Table B-1 for a list of parameters.
Step 12 To add another parameter, repeat Steps 5 through 11 for each new parameter.
Step 13 To change other parameters, repeat Steps 9 through 11 for each parameter.
Step 14 Close the Registry Editor window.
Step 15 Reboot the server for the new changes to take effect.
