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 D-1, you do not need to make any changes. However, if necessary, you can change these settings by editing the Windows 2000 registry.
Determine the need to change the default bandwidth parameters based on the peak number of users expected on the BBSM server, while considering that even if the maximum number of users is exceeded occasionally and performance is impacted, BBSM continues to operate correctly.
Note 
Note that you can only make these changes locally, not from a remote server.
Caution Incorrect registry settings can render your BBSM server unusable. Alter only the parameters listed in
Table D-1. Always backup the registry before making any changes.
Table D-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), the client must select a transmission rate below the bandwidth limit to avoid losing packets due to queue overflow. The default is 151,400 bytes.
|
PacketPoolSize
|
The number of packet descriptors. The default is 50 descriptors.
|
LookaheadPoolSize
|
The number of look-ahead buffer descriptors, which is indicated by the packet descriptor. Set PacketPoolSize and LookaheadPoolSize greater than the anticipated maximum number of packets queued for bandwidth management. The default is 50 descriptors.
•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 six packets per TCP client.
•For UDP clients, this number is the BTWQueueSize divided by the packet size. Calculate both and select the larger of the two values. For example, assume that the BWTQueueSize is 15140 Kb. Because the Ethernet packet size is 1514 bytes, divide the BWTQueueSize (15140) by 1514 bytes to establish 10 packets per client. Because 10 is greater than 6, 10 packets per client would be used.
|
Step 1 Choose Start > Run. The Run window appears. (See Figure D-1.)
Figure D-1 Run Window
Step 2 Enter regedit.
Step 3 Click OK. The Registry Editor window appears. (See Figure D-2.)
Figure D-2 Registry Editor Window
Step 4 Double-click HKEY_LOCAL_MACHINE.
Step 5 Navigate to System > CurrentControlSet > Services > ATNAT > Parameters.
Step 6 Right-click anywhere in the right pane of the Registry Editor window.
Step 7 To back up the file before making any changes, choose Registry > Export Registry File and follow the instructions.
Step 8 From the New > drop-down menu, select DWORD Value. (See Figure D-3.)
Figure D-3 Registry Editor New Drop-Down Menu
Step 9 Rename the entry to the parameter name you want to change. For applicable parameter names, see Table D-1.
Step 10 Double-click the new parameter name. (See Figure D-4. Note that BTWQueueSize is shown here only as an example.)
Figure D-4 New Parameter Name
The Edit DWORD Value dialog box appears. (See Figure D-5.)
Figure D-5 Edit DWORD Value Dialog Box
Step 11 Click Decimal.
Step 12 In the Value data field, enter the new value in the appropriate units for that parameter name. See Table D-1 for a list of parameters.
Step 13 Click OK.
Step 14 If you want to add another parameter, repeat Steps 6 through 13 for each new parameter.
Step 15 If you want to change other parameters, repeat Steps 10 through 13 for each parameter.
Step 16 When done, close the Registry Editor window.
Step 17 For the new changes to take effect, reboot the server.
