Information Technology Reference
In-Depth Information
Table18-1
Frame Relay: Frame Relay Link Is Down
Possible Problem
Solution
A cabling,
hardware, or
carrier problem
has occurred.
Perform these steps for the local and remote router:
1.
Use the
show interfaces serial
command to see whether the
interface and line protocol are up.
2.
If the interface and line protocol are down, check the cable
to make sure that it is a DTE
1
serial cable. Make sure that
cables are securely attached.
3.
If the cable is correct, try moving it to a different port. If that
port works, then the first port is defective. Replace either the
card or the router.
4.
If the cable doesn't work on the second port, try replacing
the cable. If it still doesn't work, there might be a problem
with the DCE
2
. Contact your carrier about the problem.
For detailed information on troubleshooting serial lines, refer to
Chapter 15, “Troubleshooting Serial Lines.”
An LMI
3
type
mismatch has
occurred.
1.
Use the
show interfaces serial
command to check the state
of the interface.
2.
If the output shows that the interface is up but the line
protocol is down, use the
show frame-relay lmi
exec
command to see which LMI type is configured on the Frame
Relay interface.
3.
Make sure that the LMI type is the same for all devices in the
path from source to destination. Use the
frame-relay
lmi-type
{
ansi
|
cisco
|
q933a
} interface configuration
command to change the LMI type on the router.
Keepalives are not
being sent.
Enter the
show interfaces
command to find out whether
keepalives are configured. If you see a line that says
“keepalives not set,” keepalives are not configured.
1.
Use the
keepalive
seconds
interface configuration command
to configure keepalives. The default value for this command
is 10 seconds.
2.
Encapsulation
mismatch has
occurred.
1.
When connecting Cisco devices with non-Cisco devices, you
must use IETF
4
encapsulation on both devices. Check the
encapsulation type on the Cisco device with the
show
frame-relay map
exec command.
2.
If the Cisco device is not using IETF encapsulation, use
the
encapsulation frame-relay ietf
interface configuration
command to configure IETF encapsulation on the Cisco
Frame Relay interface.
For information on viewing or changing the configuration of the
non-Cisco device, refer to the vendor documentation.
