TXP(4) BSD Kernel Interfaces Manual TXP(4)


txp — 3Com 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 driver is not present in FreeBSD 13.0 and later. See for more information.


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:

media autoselect

Attempt to autoselect the media type (default)

media 100baseTX mediaopt full-duplex

Use 100baseTX, full duplex

media 100baseTX [mediaopt half-duplex]

Use 100baseTX, half duplex

media 10baseT mediaopt full-duplex

Use 10baseT, full duplex

media 10baseT [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.

BSD October 24, 2018 BSD