Cisco WS-C2950-24 Software Configuration Guide - Page 298
Troubleshooting LRE Port Configuration
View all Cisco WS-C2950-24 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 298 highlights
Troubleshooting LRE Port Configuration Chapter 9 Troubleshooting Troubleshooting LRE Port Configuration Table 9-2 lists problems you might encounter when configuring and monitoring the Long-Reach Ethernet (LRE) ports on the Catalyst 2900 LRE XL switches. Table 9-2 LRE Port Problems Problem Suggested Solution LRE port LED is amber The switch and CPE are unable to establish a LRE link using the selected profile. Change to a profile using a lower quadrature amplitude modulation (QAM) rate. Reduce the effect of stubs or bridge taps by terminating them with 300-Ohm microfilters. Excessive CRC errors on a LRE link • A noisy environment (such as motors and power surges) is causing interference with the LRE link. Ensure that the interleaver is set to maximum protection (the interleaver trades latency for noise immunity). Change to a profile using a lower QAM rate, which increases the noise margin. • The LRE link length and quality are close to the limit of operation. Change to a profile using a lower QAM rate. 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. Ensure that the interleaver is set to maximum protection (the interleaver trades latency for noise immunity). Change to a profile using a lower QAM rate, which increases the noise margin. • The LRE link length and quality are close to the limit of operation. Change to a profile using a lower QAM rate. Reduce the effect of stubs or bridge taps by terminating them with 300-Ohm microfilters. Ethernet performance degradation due to excessive network latency Interleaver introduces extra latency to increase noise margin. Reduce the interleaver setting while ensuring the noise margin is adequate. If necessary, change to a profile using a lower QAM rate. LRE link quality reduced in Cross-talk between the LRE links is causing all links to degrade. Disable installations with bundled unused LRE ports by using the lre shutdown interface configuration cables command. Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide 9-4 78-6511-05