5-17
Catalyst 4500 E-Series Switches Installation Guide
OL-13972-01
Chapter 5 Troubleshooting
Troubleshooting Supervisor Engines
Boot Problems
If the switch is in a continuous boot loop, is in ROMmon mode, or does not have a system image, there
is mostly likely not a hardware problem. The supervisor engine opera tes in a continuous loop if you have
not set the boot variable correctly and you have set the configuration register to 0x2102 . For instructions
on how to recover the supervisor engine, refer to the “Recovering from a Continuous Reboot” section of
the document at this location:
http://www.cisco.com/en/US/products/hw/switches/ps663/products_configuration_example09186a008
0094ecf.shtml
The supervisor engine goes into ROMmon mode or fails to boot when the system image is either corrupt
or absent. For instructions on how to recover the supervisor engine, refer to the “Recovering from a
Corrupt or Missing Image” section of the document at thi s location:
http://www.cisco.com/en/US/products/hw/switches/ps663/products_configuration_example09186a008
0094ecf.shtml
The supervisor engines have onboard system Flash memory (bootflash), whic h should easily hold
multiple system images. Therefore, have a backup image. In addition to the bootflash, the supervisor
engine supports up to 128 MB of compact Flash in the slot0: device. The su pervisor engine also provides
for transfer via TFTP of the image from ROMmon mode, which ena bles faster recovery of absent or
corrupt images.

Cannot Connect to a Switch Through the Console Port

Make sure you are using the correct type of cable. Make sure the terminal configuration matches the
switch console port configuration—default console port settings are 9600 baud, 8 data bits, no parity,
1 stop bit. Make sure the cable pinouts are correct for your supervisor engine (refer to the ha rdware
documentation for your supervisor engine).

Cannot communicate with another device, Cannot Telnet to the switch, Cannot communicate with a local or remote host

Follow these steps:
Step 1 Make sure the LINK LED for the port is green.
Step 2 Check the cabling:
• Host-to-switch 10BASET connections and router-to-switch 10BASET or 100BASETX connections
typically are made using a straight-through cable.
• Switch-to-switch connections typically are made using a rollover cable.
• For SC- or ST-type fiber connections, make sure transmit (Tx) on one end of the link connec ts to
receive (Rx) on the other end of the link.
Step 3 Make sure the interface you are connecting to (sc0 or me1) is configured UP (use the show interface
command to check).
Step 4 Make sure the IP address, subnet mask, and VLAN membership of the switch interface (sc0 or me1) is
correct (use the show interface command).
Step 5 To prevent conflicts, make sure the me1 and sc0 interfaces are configured with IP addresses and subnet
masks in different subnets (use the show interface command to check), or disable one of the interfaces
using the set interface {sc0 | me1} disable command.
Step 6 Make sure the host configuration (IP address, subnet mask, default gateway, speed, and duplex setting)
is correct.