Information Technology Reference
In-Depth Information
X.25: Excess Serial Errors on X.25 Link
Symptom:
The output of the
show interfaces serial
command shows REJs, RNRs, FRMRs,
RESTARTs, or DISCs in excess of 0.5 percent of information frames (IFRAMEs).
If any of these fields are increasing and represent more than 0.5 percent of the number of
IFRAMEs, there is probably a problem somewhere in the X.25 network. There should
always be at least one SABM. However, if there are more than 10, the packet switch
probably is not responding.
Note
Table 19-2 outlines the problem that might cause this symptom and describes solutions to that problem.
Table19-2
X.25: Excess Serial Errors on X.25 Link
Possible Problem
Solution
Incorrect cabling
or bad router
hardware
Use the
show interfaces serial
exec command to determine
the status of the interface.
1.
If the interface is down, refer to Chapter 15. If the interface
is up but the line protocol is down, check the LAPB state in
the output of the
show interfaces serial
command.
2.
If the LAPB state is not CONNECT, use the
debug lapb
privileged exec command (or attach a serial analyzer) to look
for SABMs being sent and for UA packets being sent in reply
to SABMs.
3.
If the
show interfaces serial
exec command indicates that
the interface and line protocol are up but no connections can
be made, there is probably a router or switch
misconfiguration.
4.
Check all cabling and hardware for damage or wear. Replace
cabling or hardware as required. For more information, refer
to Chapter 3.
5.
