HP-UX 11i Version 1 Installation and Update Guide, June 2003

Configuring Built-In PCI Networking
PCI 10/100Base-TX and 100Base-FX/9000
Appendix D206
The fiber card (100Base-FX/9000) operates at 100 Mbit/s and in
half-duplex mode only. It does not support autonegotiation or
autosensing.
NOTE If the PCI 10/100Base-TX/9000 card is connected to a device that does
not support autonegotiation or a device that has autonegotiation disabled,
the PCI card will autosense the speed of the link and set itself accordingly.
The card will be set to half-duplex in this case. If you want the card
to operate in full-duplex mode, you have to set it using the method
described previously in “Manual Speed and Duplex Mode Configuration.”
The PCI 10/100Base-TX card will sense when the connection between
itself and a hub or switch on the other end of a link has been broken. If a
connection is made to another (or the same) device, the autosensing
process will be done again automatically. Autosensing is also done
whenever the interface is reset.
RJ-45 and AUI Ports
The 10/100 Base-TX link works with both an RJ-45 and (on the V-class)
an AUI port. The RJ-45 port can be used for either 100 Base-T or 10
Base-T networking; the AUI port is used only for 10 Base-T. Only one of
these ports should be connected to a network at any given time. The link
will normally attempt to automatically sense which port is connected
and configure that port, unless this is overridden via the Boot Time LAN
configuration described above.
If the RJ45 port is not connected to the network, the system will
configure itself to use the AUI port during boot-up or reset.
Performance
The 100 Base-T product is initially set with a conservative value for the
transmit threshold (that is, the number of bytes that must be in the
transmit FIFO buffer before transmission can begin). The transmit
threshold is set to a “store and forward” value. This means that the
entire Ethernet frame must be in the transmit FIFO before transmission
of data onto the wire will begin.