---
name: "txp"
section: "4"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux", "openbsd"]
url: "https://new.carta.tech/txp"
---

# txp(4)

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

## NAME

**txp** – 3Com 3XP Typhoon/Sidewinder (3CR990) Ethernet interface

## SYNOPSIS

To compile support for the

**txp** driver into your kernel, place the following line in your kernel configuration file:

**device txp**

Alternatively, to load the

**txp** driver at boot time, place the following line in [loader.conf(5)](/loader.conf/5.md):

```
if_txp_load="YES"
```

## DESCRIPTION

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)](/vlan/4.md) tag removal and insertion assistance, receive [ip(4)](/ip/4.md), [tcp(4)](/tcp/4.md), and [udp(4)](/udp/4.md) checksum offloading, and transmit [ip(4)](/ip/4.md) checksum offloading. There is currently no support for transmit [tcp(4)](/tcp/4.md) or [udp(4)](/udp/4.md) checksum offloading, [tcp(4)](/tcp/4.md) segmentation, nor [ipsec(4)](/ipsec/4.md) acceleration. Note that hardware checksumming is only used when the interface is not in [bridge(4)](/bridge/4.md) mode.

Each of the host's network addresses is specified at boot time with an SIOCSIFADDR [ioctl(2)](/ioctl/2.md). The **txp** interface employs the address resolution protocol described in [arp(4)](/arp/4.md) to dynamically map between Internet and Ethernet addresses on the local network.

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)](/ifconfig/8.md) 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

## HARDWARE

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

## SEE ALSO

[arp(4)](/arp/4.md), [inet(4)](/inet/4.md), [intro(4)](/intro/4.md), [ip(4)](/ip/4.md), [miibus(4)](/miibus/4.md), [tcp(4)](/tcp/4.md), [udp(4)](/udp/4.md), [vlan(4)](/vlan/4.md), [ifconfig(8)](/ifconfig/8.md)

## HISTORY

The **txp** driver first appeared in OpenBSD 2.9.