Troubleshooting guide
10-7
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 10 Troubleshooting Ethernet, ATM Uplink, and POS Uplink Interfaces
Troubleshooting General Ethernet Interface Problems
• If it is only a port stuck failure, isolate the port from the other functional ports.
• Depending on the configuration option for reset of the stuck port, one of the following actions will
occur:
–
Default behavior
If the switch router is not configured to reset the port upon detecting a port stuck failure, the
port will be isolated, thus preserving the integrity of the switch router.
–
Nondefault behavior
If the switch router is configured to reset the port upon detection of a stuck port failure, the
switch router will isolate the port from the rest of the functioning ports, and reset the port. This
might affect other ports on the interface module.
Note If you configure the switch router as described in the nondefault behavior section after a port stuck
failure is detected, the switch router will not reset the Ethernet ports. The Ethernet interface must be
configured to reset before the port stuck failure occurs. Also, the default behavior is to not reset the
port if a port stuck failure is detected. If the Ethernet interface is not configured to reset when a port
stuck failure is detected, schedule the switch router for downtime to remove and reinsert the module.
To configure the switch router to automatically recover from port stuck failures, use the following
interface configuration commands:
Caution Because of the nature of the microcode architecture, do not configure low values for the wait time in
the epc portstuck-wait command. The default value of 180 seconds has been carefully chosen,
allowing for the hello intervals of protocols such as HSRP, EIGRP, and OSPF. Configuring a low
value might lead to incorrectly detecting temporary port stuck failures as real port stuck failures, and
can cause a temporary loss of connectivity. It is highly recommended to keep this value to at 60
seconds, at a minimum. Lower values are provided to allow for some specific network designs when
you can absolutely rule out temporary port stuck failure scenarios, and also as a debugging aid. For
most networks, 180 seconds works very well.
Command Purpose
Switch(config-if)# epc port-reload Enables automatic resetting and reloading of the
interface module microcode after detecting a port
stuck failure.
Switch(config-if)# epc portstuck-wait seconds Specifies the delay before signaling a port stuck
failure (from the time the failure is detected). The
default is 180 seconds. The range for seconds is
0 to 200. A value of 0 seconds causes a port stuck
failure to not be detected.