HP StorageWorks 2/16 - SAN Switch Manual page 185

For each hop, statistics are divided into basic and extended. They are reported below the
routing information, separated into input port statistics and output port statistics. For each port,
they are further separated into transmit and receive statistics. Statistics are not reported for the
embedded port.
Some values are measured over multiple time intervals. For example, the output line utilization
in bytes per second is calculated over both a 1-second period and over a 64-second period.
This gives an idea of both the current line utilization and the utilization over a longer period of
time. The time interval is reported in parenthesis after the value's description.
Maximum hop count
The pathinfo command uses a special frame that is sent hop-by-hop from the source switch
to the destination switch, collecting routing and statistics information at every hop. To prevent
such a frame from looping forever if an error occurs, a maximum number of hops for the frame
to hop is enforced. The hop count includes all hops in the direct path from source to
destination, and also all the hops in the reverse path, if tracing of the reverse path is requested.
The default value for the maximum hop count is 25.
Basic statistics
Basic statistics report variables that give an indication of ISL congestion along the path. They
consist of the following:
B/s
Txcrdz
Extended statistics
Extended statistics report variables are:
F/s
Words
Frames
Errors
Reverse path
The path from port A on switch X to port B on switch Y might be different from the path from
port B to port A. The difference could be in the links traversed between the same sequence of
switches, or the reverse path might even involve different switches. The trace reverse path
option allows the user to determine both routing and statistics information for the reverse path,
in addition to those for the direct path.
Fabric OS 3.x Document Addendum
Bytes per second
The length of time, in milliseconds, that the port was prevented
from transmitting frames due to lack of buffer-to-buffer credit.
It is an indication of downstream congestion. Other commands,
such as portstatsshow, can express this value in units other than
milliseconds.
Frames per second
Total number of 4-byte Fibre Channel words
Total number of frames
Total number of errors that might cause a frame not to be
received correctly. This includes CRC errors, bad EOF errors,
frame truncated errors, frame too short errors, and encoding
errors inside a frame.
Fabric OS reference guide
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