Duplex Mode Setting; Speed Mode; Output Hang; Crc Field Counters - Cisco 10720 - Internet Router Installation And Configuration Manual

Chapter 4 Troubleshooting

Duplex Mode Setting

The local interface duplex mode configuration should match the remote interface configuration. See the
"Verifying Interface Configuration" section on page 4-19
settings. Confirm that duplex settings are the same on both ends of the connection.

Speed Mode

The local interface speed mode field should match the remote interface configuration. See the
Interface Configuration" section on page 4-19
setting display is shown in the following line:
10/100/auto

Output Hang

The output hang provides the number of hours, minutes, and seconds since the last reset caused by a
lengthy transmission. For example, the output hang data is located on line 9 of the show interfaces
GigabitEthernet 2/1 router output:
Last input never, output 00:00:04, output hang never
See the
shows output hang data.

CRC Field Counters

Excessive noise will cause high CRC errors accompanied by a low number of collisions. Perform the
following checks if you encounter high CRC errors:
•
•

Late Collision

The console will display the following message when late collisions are detected:
Port 2/X - Late collision detected. Possible duplex mismatch.
Late collisions result from either of the following conditions:
•
•
For example, the late collisions data is located on line 22 of the show interfaces FastEthernet 2/1 router
output:
0 babbles, 0 late collision, 0 deferred
78-13062-10
"Verifying Interface Configuration" section on page 4-19
Check the cables for damage.
Verify that the correct cables are being used for the appropriate access card. For cabling
specifications, refer to the Cisco 10720 Internet Router Access Card Installation and Configuration
publication.
Ethernet cables are too long.
Duplex mode does not match the remote interface.
Basic Troubleshooting Ethernet for the Access Card
for an example output that shows duplex
for an example output that shows speed settings. Speed
Cisco 10720 Internet Router Installation and Configuration Guide
for a complete example output that
"Verifying
4-21