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AIX Version 4.3 Kernel and Subsystems Technical Reference, Volume 2

CIO_START (Start Device) entioctl Ethernet Device Handler Operation


Establishes a session with the Ethernet device handler.


The CIO_START operation establishes a session with the Ethernet device handler. The caller notifies the device handler of the network ID that it will use. The caller can issue multiple CIO_START operations. For each successful start issued, there should be a corresponding CIO_HALT operation issued.

If the CIO_START operation is the first issued, the device handler initializes and opens the Ethernet adapter. When the first CIO_START operation successfully completes, the adapter is ready to transmit and receive data. The Ethernet adapter can receive the following packet types:

The Ethernet device handler allows a maximum of 32 network IDs. The network ID must correspond to the type field in a standard Ethernet packet or the destination service access point (DSAP) address in an IEEE 802.3 packet.

For the CIO_START operation, the arg parameter points to a session_blk structure. This structure is defined in the /usr/include/sys/comio.h file and contains the following fields:

status There are four possible returned status values:
netid Specifies the network ID the caller uses on the network. When IEEE 802.3 Ethernet is being used, the network ID is placed in the least significant byte of the netid field.
Note: The Ethernet device handler does not allow the caller to specify itself as the wildcard network ID.
length This field is used to specify the number of valid bytes in the netid field for mixed Ethernet. Valid values are 1 or 2 .

After the CIO_START operation has successfully completed, the caller is free to issue any valid Ethernet command.

Note: The Ethernet device handler does not support indiscriminate addressing.

Execution Environment

A CIO_START operation can be called from the process environment only.

Return Values

The return codes for the CIO_START operation are the following:

ENETUNREACH Indicates the operation was unable to reach the network.
EBUSY Indicates the open request was denied because the device was already open in Diagnostic mode or because the adapter was busy.
ENODEV Indicates no such device exists.
ENXIO Indicates an attempt to use an unconfigured device.
ENOSPC Indicates the netid table is full.
EADDRINUSE Indicates a duplicate network ID.

Implementation Specifics

The CIO_START operation functions with an Ethernet High-Performance LAN adapter that has been correctly configured for use on a qualified network. Consult the adapter specifications for more information on configuring the network adapter and network qualifications.

Related Information

The CIO_HALT entioctl Ethernet Device Handler Operation.

The entioctl entry point.

Common Communications Status and Exception Codes in AIX Kernel Extensions and Device Support Programming Concepts.

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