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en(4) [bsd man page]

EN(4)							     Kernel Interfaces Manual							     EN(4)

NAME
en - Xerox 3 Mb/s Ethernet interface SYNOPSIS
/sys/conf/SYSTEM: NEN en_controllers # Xerox prototype (3 Mb) Ethernet DESCRIPTION
The en interface provides access to a 3 Mb/s Ethernet network. Due to limitations in the hardware, DMA transfers to and from the network must take place in the lower 64K bytes of the UNIBUS address space, and thus this must be among the first UNIBUS devices enabled after boot. Each of the host's network addresses is specified at boot time with an SIOCSIFADDR ioctl. The station address is discovered by probing the on-board Ethernet address register, and is used to verify the protocol addresses. No packets will be sent or accepted until a network address is supplied. The interface software implements an exponential backoff algorithm when notified of a collision on the cable. This algorithm utilizes a 16-bit mask and the VAX-11's interval timer in calculating a series of random backoff values. The algorithm is as follows: 1. Initialize the mask to be all 1's. 2. If the mask is zero, 16 retries have been made and we give up. 3. Shift the mask left one bit and formulate a backoff by masking the interval timer with the mask (this is actually the two's complement of the value). 4. Use the value calculated in step 3 to delay before retransmitting the packet. The interface handles both Internet and NS protocol families. It normally tries to use a ``trailer'' encapsulation to minimize copying data on input and output. The use of trailers is negotiated with ARP. This negotiation may be disabled, on a per-interface basis, by set- ting the IFF_NOTRAILERS flag with an SIOCSIFFLAGS ioctl. DIAGNOSTICS
en%d: output error. The hardware indicated an error on the previous transmission. en%d: send error. After 16 retransmissions using the exponential backoff algorithm described above, the packet was dropped. en%d: input error. The hardware indicated an error in reading a packet off the cable. en%d: can't handle af%d. The interface was handed a message with addresses formatted in an unsuitable address family; the packet was dropped. SEE ALSO
intro(4N), inet(4F) BUGS
The device has insufficient buffering to handle back to back packets. This makes use in a production environment painful. The hardware does word at a time DMA without byte swapping. To compensate, byte swapping of user data must either be done by the user or by the system. A kludge to byte swap only IP packets is provided if the ENF_SWABIPS flag is defined in the driver and set at boot time with an SIOCSIFFLAGS ioctl. 3rd Berkeley Distribution August 20, 1987 EN(4)

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ne(4)							     Kernel Interfaces Manual							     ne(4)

Name
       ne - Second Generation Ethernet Chip Interface

Syntax
       device ne0 at ibus? vector neintr

Description
       The interface provides access to a 10 Mb/s Ethernet network through the Digital's Second Generation Ethernet Chip (SGEC) based controller.

       The  host's  Internet  address  is specified at boot time with an SIOCSIFADDR ioctl.  The interface employs the address resolution protocol
       described in to map dynamically between Internet and Ethernet addresses on the local network.

       The driver normally tries to use a trailer encapsulation to minimize copying data on input and output.  This can be disabled for an  inter-
       face by setting the IFF_NOTRAILERS flag with an SIOCSIFFLAGS ioctl.  Trailers are only used for packets destined for Internet hosts.

       The SIOCSPHYSADDR ioctl can be used to change the physical address of the adapter and the SIOCRPHYSADDR ioctl can be used to read its phys-
       ical address.

       The SIOCADDMULTI and SIOCDELMULTI ioctls can be used to add or delete multicast addresses.   The  recognizes  a	maximum  of  16  multicast
       addresses.

       The SIOCRDCTRS and SIOCRDZCTRS ioctls can be used to read or read and clear the Ethernet driver counters.  The argument to these two ioctls
       is a pointer to a counter structure, found in

       The SIOCENABLBACK and SIOCDISABLBACK ioctls can be used to enable and disable the interface loopback mode respectively.

Diagnostics
       The diagnostic error messages contain relevant information provided by the driver. For example,

       ne%d: self test failed <reason lists>
       Adapter did not pass the power-up self-test during autoconfiguration time.

       ne%d: write CSR0 failed
       The driver was unable to set the initial value for the adapter.

       ne%d: couldn't allocate ......
       The driver was unable to allocate memory for the internal data structures.  ne%d: can't handle af%d
       The interface was handed a message with addresses formated in an unsuitable address family, and the packet was dropped.

       ne%d: memory error (MERR)
       A host memory problem or a memory parity error has occurred.

       ne%d: SIOCADDMULTI fail, multicast list full
       Too many multicast requests have been made.

See Also
       arp(4p), inet(4f), intro(4n)

																	     ne(4)
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