Administrator Guide

Fabric Watch Administrator’s Guide 55
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Chapter
7
Port Monitoring
In this chapter
•Port class areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
•Port class guidelines and default settings. . . . . . . . . . . . . . . . . . . . . . . . . . . 56
•Port configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
•portThConfig command procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
•Port fencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
•Recommended port configuration settings . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Port class areas
Table 15 lists and describes the Fabric Watch areas in the Port class. You can use the portThConfig
command to configure the Port class. Port setting guidelines and specific examples of portThConfig
configurations are presented later in this chapter.
NOTE
Fabric Watch monitors and reports the status of physical and virtual FC ports. Physical GbE ports
and ISCSI ports are not monitored and are not included in the Port Class area.
TABLE 15 Port class areas
Area Description
Cyclic redundancy check
(CRC)
The number of times an invalid cyclic redundancy check error occurs on a port or
a frame that computes to an invalid CRC. Invalid CRCs can represent noise on the
network. Such frames are recoverable by retransmission. Invalid CRCs can
indicate a potential hardware problem.
Invalid transmission words
(ITW)
The number of times an invalid transmission word error occurs on a port. A word
did not transmit successfully, resulting in encoding errors. Invalid word messages
usually indicate a hardware problem.
NOTE: For Fabric OS versions 7.1.0 and later, the ITW counter includes a physical
coding sublayer (PCS) violation. ITW violations can occur due to an ITW
violation, a PCS violation, or both.
Class 3 discards (C3TX_TO) The number of Class 3 discards frames because of time outs.
Link loss (LOS) The number of times a link failure occurs on a port or sends or receives NOS.
Both physical and hardware problems can cause link failures. Link failures also
frequently occur due to a loss of synchronization or a loss of signal.
Signal loss The number of times that a signal loss occurs in a port. Signal loss indicates that
no data is moving through the port. A loss of signal usually indicates a hardware
problem.