Table 9. DOS and OS/2 NDIS device driver parameters in PROTOCOL.INI (continued)

Parameter

Explanation

MaxTxFrameSize (OS/2

This parameter specifies the maximum frame size that can be transmitted on the LAN. The

only)

parameter value serves as an upper limit. The actual maximum frame size might be smaller.

 

The maximum frame size supported by the NDIS device driver is the lesser of the following

 

values:

 

 

v The value of this MaxTxFrameSize parameter

 

v Total Receive Buffer Area (see the MinRcvBuffs parameter)

 

v The physical frame size capacity of the network (4500 bytes for 4-Mbps token rings and

 

18,200 bytes for 16-Mbps and 100-Mbps token rings)

 

Do not count the 4 bytes of FCS defined for a frame when setting this parameter value.

 

In some environments, performance can be increased by operating server and client at

 

larger frame sizes. Protocol frame size should be adjusted if this parameter is changed.

 

Note: Some token-ring switches support a maximum frame size of 4500 bytes.

 

Valid values: 14 to 18,000

 

The default is 4500.

 

 

MinRcvBuffs (OS/2 only)

This parameter specifies the minimum number of receive buffers that are allocated. The

 

Total Receive Buffer Area for the adapter is calculated using the following formula:

 

Total Receive Buffer Area = MinRcvBuffs RcvBuffSize

 

Note: To receive the maximum length frame that is supported by the attached network, the

 

Total Receive Buffer Area must be larger than the maximum frame size that is allowed for

 

the network, which is 4500 bytes for 4-Mbps Token Rings and 18 000 bytes for 16-Mbps and

 

100-Mbps Token Rings).

 

A smaller Total Receive Buffer Area will use less system memory but will correspondingly

 

reduce the size of the largest frame that can be received by the NDIS device driver. The

 

maximum frame size supported by the driver can be further limited by the MaxTxFrameSize

 

parameter.

 

Valid values: 1 to 512

 

The default is 20.

 

 

RcvBuffSize (OS/2 only)

This parameter specifies the size of each receive buffer.

 

Valid values: 256 to 18 000

 

The default is 2252.

 

 

FullDuplex

This parameter permits the device driver to activate token-ring full-duplex operation if

 

supported by the network. The MaxTxFrameSize parameter may need to be adjusted

 

separately, depending on network requirements.

 

Valid values:

 

Yes

Permits full-duplex operation.

 

No

Prohibits full-duplex operation.

The default is Yes.

54IBM 16/4 Token-Ring PCI Management Adapter

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IBM 16/4 Token-Ring manual Parameter Explanation, Valid values 14 to 18,000, Valid values 1 to, Valid values 256 to 18, Yes