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TXP(4) Device Drivers Manual TXP(4)


txp3Com 3XP Typhoon/Sidewinder (3CR990) Ethernet interface


To compile this driver into the kernel, place the following line in your kernel configuration file:

device txp

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):



The txp interface provides access to the 10Mb/s and 100Mb/s Ethernet networks via the 3Com Typhoon/Sidewinder chipset.

Basic Ethernet functions are provided as well as support for vlan(4) tag removal and insertion assistance, receive ip(4), tcp(4), and udp(4) checksum offloading, and transmit ip(4) checksum offloading. There is currently no support for transmit tcp(4) or udp(4) checksum offloading, tcp(4) segmentation, nor ipsec(4) acceleration.

When a txp interface is brought up, by default, it will attempt to auto-negotiate the link speed and duplex mode. The speeds, in order of attempt, are: 100Mb/s Full Duplex, 100Mb/s Half Duplex, 10 Mb/s Full Duplex, and 10 Mb/s Half Duplex.

The txp supports several media types, which are selected via the ifconfig(8) command. The supported media types are:

Attempt to autoselect the media type (default)
Use 100baseTX, full duplex
[mediaopt half-duplex]
Use 100baseTX, half duplex
Use 10baseT, full duplex
[mediaopt half-duplex]
Use 10baseT, half duplex


The txp driver supports the following cards:

  • 3Com 3CR990-TX-95
  • 3Com 3CR990-TX-97
  • 3Com 3cR990B-TXM
  • 3Com 3CR990SVR95
  • 3Com 3CR990SVR97
  • 3Com 3cR990B-SRV


altq(4), arp(4), inet(4), intro(4), ip(4), miibus(4), tcp(4), udp(4), vlan(4), ifconfig(8)


The txp driver first appeared in OpenBSD 2.9.

January 26, 2012 Debian