Serial Lines: Troubleshooting Serial Line Input Errors - Cisco ASR 1000 Configuration Manual

Performing Basic Interface Troubleshooting
Symptom: Increasing number of input errors in excess of 1 percent of total interface traffic
Table 20-4
Possible Problem
The following problems
can result in this
symptom:
•
•
•
•
•
•
•
•

Serial Lines: Troubleshooting Serial Line Input Errors

Table 20-5
possible problems that might be causing the errors, and solutions to those problems.
Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide
20-10
Serial Lines: Increasing Input Errors in Excess of 1 Percent of Total Interface Traffic
Solution
Note
1.
Faulty telephone
company equipment
Noisy serial line
2.
Incorrect clocking
3.
configuration
Incorrect cable or
cable that is too long
Bad cable or
connection
Bad CSU or DSU
Bad router hardware
Data converter or
other device being
used between router
and DSU
describes the various types of input errors displayed by the show interfaces serial command,
We strongly recommend against the use of data converters when
you are connecting a router to a WAN or a serial network.
Use a serial analyzer to isolate the source of the input errors. If you
detect errors, there likely is a hardware problem or a clock mismatch
in a device that is external to the router.
Use the loopback and ping tests to isolate the specific problem source.
Look for patterns. For example, if errors occur at a consistent interval,
they could be related to a periodic function, such as the sending of
routing updates.
Chapter 20 Troubleshooting the Serial SPAs
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