C H A P T E R

C H A P T E R 3

Parameter Definitions

This chapter describes the parameters and settings for the qfe device driver.

Driver Parameter Values and Definitions

The following sections describe the qfe driver parameters, which are listed in TABLE 3-1 .

Defining the Current Status , Table 3-2.
Inter-Packet Gap Parameters , Table 3-3.
Defining an Additional Delay Before Transmitting a Packet Using lance_mode and ipg0 , Table 3-4.
Operational Mode Parameters , Table 3-5.
Operational Mode Priorities , Table 3-6.
Defining the Number of Back-to-Back Packets to Transmit , Table 3-7.
Reporting Transceiver Capabilities , Table 3-8.
Reporting the Link Partner Capabilities , Table 3-9.

TABLE 3-1 `qfe` Driver Parameters, Status, and Descriptions
Parameter	Status	Description	Details
transciever_inuse	Read only	Defines the current status
`link_status`	Read only	Defines the current status	Defining the Current Status
`link_speed`	Read only	Defines the current status
`link_mode`	Read only	Defines the current status
`ipg1`	Read and write	Inter-packet gap parameter	Inter-Packet Gap Parameters
`ipg2`	Read and write	Inter-packet gap parameter	Inter-Packet Gap Parameters
`use_int_xcvr`	Read and write	Operational mode parameter
`pace_size`	Read and write	Operational mode parameter	Defining the Number of Back-to-Back Packets to Transmit
`adv_autoneg_cap`	Read and write	Operational mode parameter	Reporting Transceiver Capabilities
`adv_100fdx_cap`	Read and write	Operational mode parameter
`adv_100hdx_cap`	Read and write	Operational mode parameter
`adv_10fdx_cap`	Read and write	Operational mode parameter
`adv_10hdx_cap`	Read and write	Operational mode parameter
`autoneg_cap`	Read only	Local transceiver auto negotiation capability	Defining the Current Status
`100fdx_cap`	Read only	Local transceiver capability of the hardware
`100hdx_cap`	Read only	Local transceiver capability of the hardware
`10fdx_cap`	Read only	Local transceiver capability of the hardware
`10hdx_cap`	Read only	Local transceiver capability of the hardware
`lp_autoneg_cap`	Read only	Link partner auto negotiation capability	Reporting the Link Partner Capabilities
`lp_100fdx_cap`	Read only	Link partner capability
`lp_100hdx_cap`	Read only	Link partner capability
`lp_10fdx_cap`	Read only	Link partner capability
`lp_10hdx_cap`	Read only	Link partner capability
`instance`	Read and write	Device instance
`lance_mode`	Read and write	Additional delay before transmitting a packet	Defining an Additional Delay Before Transmitting a Packet Using lance_mode and ipg0
`ipg0`	Read and write	Additional delay before transmitting a packet

Defining the Current Status

The read-only parameters described in TABLE 3-2 explain the operational mode of the interface. These parameters define the current status. Click on this link to return to Driver Parameter Values and Definitions

TABLE 3-2 Read-Only Parameters Defining the Current Status
Parameter	Description	Values
`l ink_status`	Current link status	0 = Link down 1 = Link up
`link_speed`	Valid only if the link is up	0 = 10 Mbps 1 = 100 Mbps
`link_mode`	Valid only if the link is up	0 = Half duplex 1 = Full duplex

Inter-Packet Gap Parameters

The Fast Ethernet Parallel Port SCSI (FEPS) ASIC supports programmable Inter-Packet Gap (IPG) parameters ipg1 and ipg2 . The total IPG is the sum of ipg1 and ipg2 . The total IPG is 9.6 microseconds when the link speed set by the auto-negotiation protocol is 10 Mbps. When the link speed is 100 Mbps, the total IPG is 0.96 microseconds.

TABLE 3-3 lists the default values and allowable values for the IPG parameters, ipg1 and ipg2. Click on this link to return to Driver Parameter Values and Definitions .

TABLE 3-3 Read-Write Inter-Packet Gap Parameter Values and Descriptions
Parameter	Values (Byte-time)	Description
`ipg1`	0, 255	`ipg1` = 8 (default at initialization)
`ipg2`	0, 255	`ipg2` = 4 (default at initialization)

By default, the driver sets ipg1 to 8-byte time and ipg2 to 4-byte time, which are the standard values. (Byte time is the time it takes to transmit one byte on the link, with a link speed of either 100 Mbps or 10 Mbps.)

If your network has systems that use longer IPG (the sum of ipg1 and ipg2 ) and if those machines seem to be slow in accessing the network, increase the values of ipg1 and ipg2 to match the longer IPGs of other machines.

Defining an Additional Delay Before Transmitting a Packet Using lance_mode and ipg0

The following two ASICs support a programmable mode called lance_mode . The ipg0 parameter is associated with lance_mode :

Fast Ethernet Parallel Port SCSI (FEPS) for SBus)
PCI Fast Ethernet and Expansion (PFEX for PCI)

After a packet is received with lance_mode enabled (default) an additional delay is added by setting the ipg0 parameter before transmitting the packet. This delay, set by the ipg0 parameter, is in addition to the delay set by the ipg1 and ipg2 parameters. The additional delay set by ipg0 helps to reduce collisions. Systems that have lance_mode enabled might not have enough time on the network.

If lance_mode is disabled, the value of ipg0 is ignored and no additional delay is set. Only the delays set by ipg1 and ipg2 are used. Disable lance_mode if other systems keep sending a large number of back-to-back packets.

You can set the additional delay with the ipg0 parameter from 0 to 31, which is the nibble time delay. Nibble time is the time it takes to transfer four bits on the link. If the link speed is 10 Mbps, nibble time is equal to 400 ns. If the link speed is 100 Mbps, nibble time is equal to 40 ns.

For example, if the link speed is 10 Mbps, and you set ipg0 to 20 nibble times, multiply 20 by 400 ns to get 8000 ns. If the link speed is 100 Mbps, and you set ipg0 to 30 nibble-times, multiply 30 by 40 ns to get 1200 ns.

TABLE 3-4 defines the lance_mode and ipg0 parameters. Click on this link to return to Driver Parameter Values and Definitions .

TABLE 3-4 Parameters Defining `lance_mode` and `ipg0`
Parameter	Values	Description
`lance_mode`	0 1	`lance_mode` disabled `lance_mode` enabled (default)
`ipg0`	0-31 -- See the following Note	Additional IPG before transmitting a packet (after receiving a packet)

Note Note - The default value for ipg0 is 16 nibble-times, which is 6.4 microseconds for 10 Mbps and 0.64 microseconds for 100 Mbps.

Operational Mode Parameters

TABLE 3-5 describes the operational mode parameters and their default values. Click on this link to return to Driver Parameter Values and Definitions .

TABLE 3-5 Operational Mode Parameters
Parameter	Description	Values
`adv_autoneg_cap`	Local transceiver capability advertised by the hardware	0 = Forced mode 1 = Auto-negotiation (default)
`adv_100fdx_cap`	Local transceiver capability advertised by the hardware; read/write parameter	0 = Not 100 Mbit/sec full-duplex capable 1 = 100 Mbit/sec full-duplex capable (default)
`adv_100hdx_cap`	Local transceiver capability advertised by the hardware; read/write parameter	0 = Not 100 Mbit/sec half-duplex capable 1 = 100 Mbit/sec half-duplex capable (default)
`adv_10fdx_cap`	Local transceiver capability advertised by the hardware; read/write parameter	0 = Not 10 Mbit/sec full-duplex capable 1 = 10 Mbit/sec full-duplex capable (default)
`adv_10hdx_cap`	Local transceiver capability advertised by the hardware; read/write parameter	0 = Not 10 Mbit/sec half-duplex capable 1 = 10 Mbit/sec half-duplex capable (default)

Operational Mode Priorities

TABLE 3-6 lists the priority of the operational mode parameters. When the Sun qfe FastEthernet Device Driver negotiates with a partner on the network, it implements the operational mode in the order shown in TABLE 3-6 . Click on this link to return to Driver Parameter Values and Definitions .

TABLE 3-6 Operational Mode Priorities
Priority	Parameter
First	adv_100fdx_cap
Second	adv_100hdx_cap
Third	adv_10fdx_cap
Fourth	adv_10hdx_cap

Defining the Number of Back-to-Back Packets to Transmit

The pace_size parameter (see TABLE 3-7 ) defines the maximum number of back-to-back packets you can transmit at one time. If the value is zero, there is no limit to the number of back-to-back packets that can be transmitted. Click on this link to return to Driver Parameter Values and Definitions .

TABLE 3-7 Back-to-Back Packet Transmission Capability
Parameter	Values	Description
`pace_size`	1 to 255 0	Number of back-to-back packets transmitted at one time No limit to the number of back-to-back packets that can be transmitted (default)

Reporting Transceiver Capabilities

TABLE 3-8 describes the read-only transceiver capabilities (either the internal transceiver or the external transceiver), whichever is selected. Click on this link to return to Driver Parameter Values and Definitions .

TABLE 3-8 Read-Only Transceiver Capabilities
Parameter	Description	Values
`autoneg_cap`	Local transceiver capability of the hardware	0 = Not capable of auto-negotiation 1 = Auto negotiation capable
`100fdx_cap`	Local transceiver capability of the hardware; initialized at startup	0 = Not 100 Mbit/sec full-duplex capable 1 = 100 Mbit/sec full-duplex capable
`100hdx_cap`	Local transceiver capability of the hardware; initialized at startup	0 = Not 100 Mbit/sec half-duplex capable 1 = 100 Mbit/sec half-duplex capable
`10fdx_cap`	Local transceiver capability of the hardware; initialized at startup	0 = Not 10 Mbit/sec full-duplex capable 1 = 10 Mbit/sec full-duplex capable
`10hdx_cap`	Local transceiver capability of the hardware; initialized at startup	0 = Not 10 Mbit/sec half-duplex capable 1 = 10 Mbit/sec half-duplex capable

The parameters in TABLE 3-8 define the capabilities of the hardware. The internal transceiver can support all of these capabilities. The capabilities of the external transceiver are dependent on the device. If the external transceiver is not capable of auto-negotiation but has the capability of all speeds and modes (100 Mbps, 10 Mbps, half-duplex, and full-duplex), you must force the operational speed and mode of the external transceiver.

Reporting the Link Partner Capabilities

TABLE 3-9 describes the read-only link partner capabilities. Click on this link to return to Driver Parameter Values and Definitions .

TABLE 3-9 Read-Only Link Partner Capabilities
Parameter	Values
`lp_autoneg_cap`	0 = No auto-negotiation 1 = Auto-negotiation
lp_100T4_cap	0 = No 100BASE-T4 1 = 100BASE-T4
`lp_100fdx_cap`	0 = No 100 Mbit/sec full-duplex transmission 1 = 100Mbit/sec full-duplex
`lp_100hdx_cap`	0 = No 100 Mbit/sec half-duplex transmission 1 = 100 Mbit/sec half-duplex
`lp_10fdx_cap`	0 = No 10 Mbit/sec full-duplex transmission 1 = 10 Mbit/sec full-duplex
`lp_10hdx_cap`	0 = No 10 Mbit/sec half-duplex transmission 1 = 10 Mbit/sec half-duplex

If the link partner is not capable of auto-negotiation (when lp_autoneg_cap is 0) the information described in is not relevant and the parameter value = 0.

If the link partner is capable of auto-negotation (when lp_autoneg_cap is 1) then the speed and mode information is displayed when you use auto-negotiation and get the link partner capabilities

Click on this link to return to Driver Parameter Values and Definitions .