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alt(7)
NAME
  alt - DEGPA Gigabit Ethernet interface

SYNOPSIS
  config_driver	   alt

DESCRIPTION
  The alt interface provides access to Gigabit Ethernet (1000Mbs) through the
  DEGPA device.	 The interface supports full-duplex operation in a switched
  or point-to-point configuration, and provides the following features:

    ·  The interface has Link Autonegotiation enabled by default.  Some
       switches do not support Link Autonegotiation.  To turn Link
       Autonegotiation off, use the following command:

	    # lan_config -ialt0 -a0

       Note that you may add this command to the /etc/inet.local file to
       preserve the setting of Link Autonegotiation across system restarts.

       If you manually set the speed by using the ifconfig or lan_config
       commands, autonegotiation is automatically disabled. If you then want
       to enable autonegotiation (for example on interface alt0), use the
       following command:

	    # lan_config -ialt0 -a1

    ·  JUMBO packets are disabled by default.  JUMBO packets provide a non-
       standard larger packet size.  This enables the interface to carry more
       data with less CPU overhead.  To enable JUMBO packets, use the
       following command:

	    # ifconfig alt0 ipmtu 9000

       Note that there are several interoperability issues with using JUMBO
       packets (for example, if your switch goes from 1000Mbps to a 100Mbps
       client, JUMBO packets will not work on a 100Mbps LAN).  In order to
       use JUMBO frames, you will need a switch that supports JUMBO frames or
       a point-to-point configuration with a partner that supports JUMBO
       frames.

    ·  Receive flow control is enabled. There is currently no way to turn
       this off.

  For the DEGPA-SX, we strongly recommend that you use the auto-negotiation
  protocol. This protocol has been thoroughly tested, and works reliably with
  many different switch vendors over Gigabit Ethernet. If you disable auto-
  negotiation, the switch port setting and the DEGPA-SX setting must match
  perfectly, otherwise you might encounter interoperability problems. The
  DEGPA-SX (fiber optic version) runs at 1000Mbps only.

  For the DEGPA-TX (the copper version of the Gigabit Ethernet NIC), you must
  enable auto-negotiation. This is a mandatory requirement of the IEEE
  802.3ab auto-negotiation protocol. The DEGPA-TX can run at 1000, 100, or 10
  Mbps.

  Gigabit Ethernet performance with TCP/IP depends on several factors.	Some
  of the influencing factors are as follows:

  CPU speed/utilization
      The speed at which data can be delivered to the interface influences
      throughput.  If your CPU(s) are busy doing several tasks, the task
      using Gigabit Ethernet may not get enough run time to deliver packets.
      In general, faster CPUs will deliver better throughput.

  PCI Bus speed/arbitration
      Fast access to the PCI bus is critical for high throughput.  Using a
      64-bit PCI slot will give you better performance and use less PCI
      resources than a 32-bit PCI slot.	 Putting the interface on the same
      PCI bus as other peripherals will degrade throughput.  Each system type
      may also have different PCI-to-host speed considerations (the speed at
      which the PCI-to-host hardware allows the device to operate).

  Application/Transport factors
      The standard TCP/IP applications (for example, ftp and rcp) are not
      designed to run at Gigabit speeds. TCP applications that expect
      performance should use a message size of 65000 bytes and a window size
      of 128000 bytes.	Even when an application is modified to use these
      settings, high throughput may not be attainable.	This is particularly
      true when an application is waiting for data to send (data from a disk,
      for example).

ERRORS
  The following diagnostic and error messages contain relevant information
  provided by the alt interface, and are displayed to the console.  Each
  message begins with the adapter identification, including the number of the
  adapter.

  No dense or linear space available on this system
      The alt interface could not find adequate I/O addressing on this system
      to operate.  This is a fatal error, and the DEGPA-SA will not operate
      on this system.

  alt_InitNICmem failed,

  alt_InitNICph1 failed,

  alt_InitNICph2 failed
      There was a memory allocation problem or the device initialization has
      failed.  This indicates a hardware problem.

  Link up Autonegotiated ReceiveFlowControl
      Indicates that the Gigabit Ethernet link is up.  The Autonegotiated
      keyword indicates that the link was autonegotiated.  Note, this will
      only be on if autonegotiation is enabled.	 The ReceiveFlowControl
      keyword indicates that Receive Flow control is enabled on the link.

  Link down
      Indicates that the link is no longer established.	 No communication
      will occur over the link while it is down.

SEE ALSO
  Commands: ifconfig(8), lan_config(8)

  Files: inet.local(4)

  Networkinformation: arp(7), inet(7), netintro(7)

Index for Section 7

Alphabetical listing for A

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