Troubleshooting X.25
401
debug Commands
There are several debug commands associated with X.25. A few of them are
debug x25 all
, debug x25 events, debug x25 vc, debug x25 interface,
and debug lapb. The two that will be discussed in this section are the debug x25
events
and debug lapb.
debug x25 events
When the events option is used, the output does not contain any informa-
tion regarding data or Receive Ready (RR) flow control packets. Calls and
other data flow packets are not recorded because of the large amount of
output they generate.
debug lapb
This tool can be used when X.25 interfaces experience frequent restarts and
instability. X.25 relies on LAPB Layer 2 protocol for stable data link. If there
are problems with the LAPB protocol, it propagates to the X.25 protocol and
interface. The output from LAPB debugging contains information regarding
all packets and traffic that use LAPB encapsulation.
Complete documentation regarding the output from the LAPB debug
trace can be found within the documentation included in the UniverCD.
X.25 Link Summary
This section includes the quick reference guide for recognizing, diagnosing,
isolating, and resolving X.25 problems.
Symptoms and Problems
Table 7.3 contains common symptoms and their corresponding problems.
T A B L E 7 . 3
X.25 Symptoms and Problems
Symptom or Condition
Associated Problem(s)
X.25 connection failures
(a) Link is down
(b) Faulty hardware
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