Diagnosing Lre Connection Problems - Cisco Catalyst 2950 Software Configuration Manual

Diagnosing LRE Connection Problems

Diagnosing LRE Connection Problems
Table 31-2
the Catalyst 2950 LRE switches. For more information about LRE connections, see the
Guidelines for LRE Links" section on page
For switch upgrade and customer premises equipment (CPE) device upgrade troubleshooting
information, see the
Table 31-2 LRE Port Problems
Problem Suspected Cause and Suggested Solution
Amber LRE port LED The switch and CPE device are unable to establish an LRE link using the selected profile.
Excessive CRC errors
on an LRE link
High Reed-Solomon
error count without
CRC errors
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
31-18
lists problems that you might encounter when configuring and monitoring the LRE ports on
"Upgrading LRE Switch Firmware" section on page
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.
A noisy environment (such as motors and power surges) is causing interference with the LRE
•
link.
Change to a profile that has the interleave feature enabled, such as the LRE-5, LRE-10,
–
LRE-15, LRE-10-1, LRE-10-3, or LRE-10-5 profile.
Change the interleave block size value to a value other than 0.
–
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.
–
The interleave feature 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 the interleave block size value to any value other than 0.
–
– 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.
12-9.
Chapter 31 Troubleshooting
"Environmental
12-24.
78-11380-12