16. Ethernet Ports
ROX™ v2.2 User Guide
165
RuggedBackbone™ RX5000
3.
Do not connect the other end of the cable to any link partner.
4.
Run cable diagnostics a few times on the port. OPEN fault should be detected.
5.
Find the average distance to the OPEN fault recorded in the log and compare it to the known length
of the cable. The difference can be used as the calibration value.
6.
Enter the calibration value and run cable diagnostics a few more times.
7.
The distance to the OPEN fault should now be at a similar distance to the actual cable length.
8.
The distance to the fault for the selected port is now calibrated.
16.2.5. Link Detection Options
Figure 16.20. Switch (Link Detection) menu
The Switch (Link Detection) menu is accessible from the main menu under switch.
Figure 16.21. Link Detection form
The Link Detection form appears on the same screen as the switch (Link Detection) menu.
Fast Link Detection
Synopsis: string - one of the following keywords { portguard, off, on }
Default: portguard
Provides protection against faulty end devices generating an improper link integrity signal. When a
faulty end device or a mis-matching fiber port is connected to the unit, a large number of continuous
link state changes could be reported in a short period of time. This large number of bogus link state
changes could render the system unresponsive as most, if not all, of the system resources are used
to process the link state changes. This could in turn cause a serious network problem as the unit's
RSTP process may not be able to run, thus allowing a network loop to form.
Three different settings are available for this parameter:
• ON_withPortGuard: This is the recommended setting. With this setting, an extended period (~2
minutes) of excessive link state changes reported by a port will prompt Port Guard feature to
disable FAST LINK DETECTION on that port and raise an alarm. By disabling FAST LINK
DETECTION on the problematic port, excessive link state changes can no longer consume a
substantial amount of system resources. However if FAST LINK DETECTION is disabled, the
port will need a longer time to detect a link failure. This may result in a longer network recovery
