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EN(4) Device Drivers Manual EN(4)


endevice driver for Midway-based ATM interfaces


To compile this driver into the kernel, place the following lines in your kernel configuration file:

device en
device atm
device utopia

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):



The en device driver supports Midway-based ATM interfaces including the Efficient Networks, Inc. ENI-155 and Adaptec ANA-59x0. Midway is an AAL5 SAR (Segmentation and Reassembly) chip.

For configuring the card for IP see natmip(4).

The following sysctls are recognized by the driver additionally to those handled by utopia(4):

Contains an array of uint32_t with internal driver statistics.
This is a bit map of debugging options. This variable is only available when the driver is compiled with debugging support.

The driver supports the media options sdh, noscramb and unassigned (see utopia(4)).


en0 <Efficient Networks ENI-155p> rev 0 int a irq 5 on pci0:16
en0: ATM midway v0, board IDs 6.0, Utopia (pipelined), 512KB on-board RAM
en0: maximum DMA burst length = 64 bytes
en0: 7 32KB receive buffers, 8 32KB transmit buffers allocated


natm(4), natmip(4), utopia(4), ifconfig(8), route(8)


Chuck Cranor of Washington University implemented en driver in 1996 for NetBSD.


The driver extensively uses DMA on PCI. The first generation PCI chipsets do not work or exhibit poor performance.

July 16, 2005 Debian