EC(4S) — System Manager’s Manual — Special Files

NAME

ec − 3Com 10 Mb/s Ethernet interface

SYNOPSIS

device ec0 at mb0 csr 0xe0000 priority 3

DESCRIPTION

The ec interface provides access to a 10 Mb/s Ethernet network through a 3COM controller. The host’s address is discovered at boot time by reading it from the device’s command register. For a general description of network interfaces see if(4N).

The hardware consumes 8 kilobytes of Multibus memory space. This memory is used for internal buffering by the board. The board starts at standard addresses 0xE0000 or 0xE2000. The board must be configured for interrupt level 3.

The interface software implements an exponential backoff algorithm when notified of a collision on the cable.

The interface handles the Internet protocol family, with the interface address maintained in Internet format. The Address Reolution Protocol arp(4P) is used to map 32-bit Internet addresses used in inet(4F) to the 48-bit addresses used on the Ethernet.

DIAGNOSTICS

ec%d: send error. After 16 failed transmissions and backoffs using the exponential backoff algorithm described above, the packet was dropped.

ec%d: input error (offset=%d). The hardware indicated an error in reading a packet off the cable or an illegally sized packet. The buffer offset value is printed for debugging purposes.

ec%d: can’t handle af%d. The interface was handed a message with addresses formatted in an unsuitable address family; the packet was dropped.

BUGS

The PUP protocol family should be added.

The interface hardware is not capable of talking to itself, making diagnosis more difficult.

Sun System Release 1.0 — 11 August 1983

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