Cisco WS-C2960-8TC-L User Manual

9-9
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
78-6511-08
Chapter 9 Troubleshooting
Troubleshooting LRE Port Configuration
Troubleshooting LRE Port Configuration
Table 9-6 lists problems you might encounter when configuring and monitoring the Long-Reach
Ethernet (LRE) ports on the Catalyst 2900 LRE XL switches. For additional information about what can
affect LRE connections, see the “Environmental Considerations for LRE Links” section on page 7-18.
LRE command descriptions provide additional troubleshooting information. Refer to the switch
command reference.
Table 9-6 LRE Port Problems
Problem Suspected Cause and Suggested Solution
Amber LRE port LED The switch and CPE are unable to establish an LRE link using the selected profile.
• Change to a profile with a lower data rate (for example, use LRE-5 instead of LRE-15).
• Reduce the effect of stubs or bridge taps by terminating them with 300-ohm microfilters.
Excessive CRC errors
on an LRE link
• A noisy environment (such as motors and power surges) is causing interference with the LRE
link.
– Change to a profile that has the interleaver feature enabled, such as the LRE-5, LRE-10,
LRE-15, LRE-10-1, LRE-10-3, or LRE-10-5 profile.
– Change to a profile with a lower data rate (for example, use LRE-5 instead of LRE-15) to
increase the noise margin.
• The LRE link length and quality are close to the limit of operation.
– Change to a lower profile (for example, LRE-5 instead of LRE-15).
– Reduce the effect of stubs or bridge taps by terminating them with 300-ohm microfilters.
High Reed-Solomon
error count without
CRC errors
• Interleaver is helping Reed-Solomon error correction to function correctly in a noisy
environment. This situation means that the system is on the verge of generating CRC errors.
– Change to a profile that has the interleaver feature enabled, such as the LRE-5, LRE-10,
LRE-15, LRE-10-1, LRE-10-3, or LRE-10-5 profile.
– Change to a profile with a lower data rate (for example, use LRE-5 instead of LRE-15) to
increase the noise margin.
• The LRE link length and quality are close to the limit of operation.
– Change to a profile with a lower data rate (for example, use LRE-5 instead of LRE-15).
– Reduce the effect of stubs or bridge taps by terminating them with 300-ohm microfilters.

Cisco WS-C2960-8TC-L Specifications

General

Brand	Cisco
Model	WS-C2960-8TC-L
Category	Switch
Language	English