IBM Channel Attach Commands

Field

Description

Path

The path from the CLAW configuration. It tells which port on the switch is used by the channel side of the configuration.

Dev

The device address for each of the devices. For CLAW you get two device addresses. In the configuration statement, you only specify the even address.

Connects

The number of times the channel started a channel program on the device.

Command Retries

The number of times the CIP either had no data to send to the channel (for the read subchannel) or the number of times the CIP had no buffers to hold data from the channel (for the write subchannel). Every command retry that is resumed results in a connect. A command retry may be ended via a cancel.

Cancels

The host requested any outstanding operation to be terminated. It is a measure of the number of times the host program was started.

Selective Reset

Selective reset effects only one device whereas a system reset effects all devices on the given channel. It is a reset of the device. On VM this will occur whenever you have a device attached and issue a CP IPL command.

System Reset

The number of times the system IPL command was issued. There is always one when the ECA is initialized. One will also occur if the channel is taken off line.

Device Errors

Errors detected by the ECA or PCA due to problems on the link. This value should always be 0.

CU Busy

The number of times the adapter returned a control unit busy indication to the host. It will occur after a cancel or reset if the host requests an operation before the CIP has finished processing the cancel or reset.

Dev-lnk

The first number is the device address. The second number is the logical link. Link 0 is always used for CLAW control messages. For IP datagram mode, link 1 is for actual datagram traffic.

Blocks Read/Blocks Write

CLAW uses the even subchannel for reads and the odd subchannel for writes. Each count is one IP datagram or one control message.

Bytes Read/Bytes Write

Bytes is the sum of the bytes in the blocks.

Dropped Blk Read/Write

If the router switch processor sends data to the CIP faster than it can send it to the channel, then the block is dropped. High values mean the host is not running fast enough. There are drops on write too. A write drop will occur if the CIP fails to get a MEMD buffer n times for a given block. See Failed memd counter.

Failed memd

The number of times the CIP could not obtain a MEMD buffer on the first try. If this value is high, try allocating more large buffers.

Con

For link 0, connect of Y means the system validate has completed. For all other links, it means the connection request sequence has completed. Con is an abbreviation for connected.

Channel... is {up | down |
administratively down}

Indicates whether the interface hardware is currently active (whether synchronization is achieved on an ESCON channel, or if operational out is enabled on a parallel channel) and if it has been taken down by an administrator.

line protocol
is {up | down |
administratively down}

Indicates whether the software processes that handle the line protocol think the line is usable (that is, whether keepalives are successful).

Hardware is

Hardware type.

Internet address is

IP address and subnet mask.

MTU

Maximum transmission unit of the interface.

BW

Bandwidth of the interface in kilobits per second.

DLY

Delay of the interface in microseconds.

rely

Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over 5 minutes.

load

Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes. The calculation uses the value from the bandwidth interface configuration command.

Encapsulation

Encapsulation method assigned to interface.

loopback

Indicates whether loopbacks are set or not.

keepalive

Indicates whether keepalives are set or not.

daughter card

Type of adapter card.

Data transfer rate

Rate of data transfer.

Number of subchannels

Number of subchannels.

Last input

Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed.

Last output

Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.

output hang

Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds
24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.

Last clearing

The time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared. These asterisks (***) indicate the elapsed time is too large to be displayed. 0:00:00 indicates the counters were cleared more than 2³¹ms (and less than 2³²ms) ago.

Output queue, drops
input queue, drops

Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.

Five minute input rate,
Five minute output rate

Average number of bits and packets transmitted per second in the last 5 minutes.

packets input

Total number of error-free packets received by the system.

bytes input

Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system.

no buffer

Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events.

broadcasts

Total number of broadcast or multicast packets received by the interface.

runts

Number of packets that are discarded because they are smaller than the medium's minimum packet size.

giants

Number of packets that are discarded because they exceed the medium's maximum packet size.

input errors

Total number of no buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors can also increment the count, so that this sum may not balance with the other counts.

CRC

Number of code violation errors seen on the ESCON interface, where a received transmission character is recognized as invalid. On a parallel interface, the number of parity errors seen.

frame

Number of packets received incorrectly having a CRC error and a noninteger number of octets. This value is always 0.

overrun

Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data. This value is always 0.

ignored

Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be incremented.

abort

Illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment. This value is always 0.

packets output

Total number of messages transmitted by the system.

bytes

Total number of bytes, including data and MAC encapsulation, transmitted by the system.

underruns

Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this may not balance with the sum of the enumerated output errors, as some datagrams may have more than one error, and others may have errors that do not fall into any of the specifically tabulated categories.

output errors

Number of output errors.

collisions

Number of collisions detected. This value is always 0.

interface resets

Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.

On the Channel Interface Processor, this may occur if the host software is not requesting data

restarts

Number of times the controller was restarted because of errors.