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. Note that hardware checksumming is only used when the interface is not in bridge(4) mode.
Each of the hosts network addresses is specified at boot time with an SIOCSIFADDR ioctl(2). The txp interface employs the address resolution protocol described in arp(4) 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) command. The supported media types are: