Cisco 2524 - Router - EN User manual

APPENDIX
Troubleshooting the Cisco 2524 and Cisco 2525 Routers B-1
B
Troubleshooting the Cisco 2524
and Cisco 2525 Routers
This appendix describes how to troubleshoot the Cisco 2524 and Cisco 2525 routers by
referring to the LEDs on the rear panel of the chassis (see Figure 1-2 and Figure 1-3) and
on the network processor modules (see Figure 1-4 through Figure 1-9).
The LEDs indicate the current operating condition of your router. You can observe the
LEDs, note any fault condition that the router is encountering, and then contact your system
administrator or a customer service representative, if necessary. Table B-1 describes the
LEDs on the router chassis and WAN modules.
Table B-1 LEDs
Chassis/Module LED State Description
Router chassis Power On steadily Power is being supplied to the router.
Off Power is not reaching the router. Verify that the power
supply is plugged into the wall receptacle, and that the
cable from the power supply to the router is connected.
Activity
(Ethernet/
Token Ring1)
Flickering The Ethernet/Token Ring LAN connection is
transmitting and receiving data normally.
Off The Ethernet/Token Ring LAN connection is not
transmitting or receiving data. Check the
Ethernet/Token Ring cable connection.

B-2 Cisco 2524 and Cisco 2525 Router User Guide
Router chassis Ethernet link
(Cisco 2524)2
On The router senses the Ethernet 10BaseT link integrity
signal, indicating normal operation.
Off The router is not sensing the Ethernet 10BaseT link
integrity signal. Check the Ethernet 10BaseT cable
connection.
In-ring
(Cisco 2525)
On The router has been successfully inserted into the
Token Ring, indicating normal operation.
Off The router has not been successfully inserted into the
Token Ring. Check the Token Ring cable connection.
2-wire switched 56-kbps,
4-wire 56/64-kbps, and
factional T1/T1 WAN
DSU/CSU modules
RX On Data is being received at the DTE interface.
TX On Data is transmitting from the DTE interface.
CD (Carrier) On The DSU/CSU in the module is communicating with
another DSU/CSU.
Loopback On The DSU/CSU is in loopback mode.
Alarm On An alarm condition is present.
Serial module Activity (serial
activity)
Flickering The serial WAN connection is transmitting and
receiving data normally.
Off The serial WAN connection is not transmitting or
receiving data. Check the serial cable connection.
ISDN BRI module Activity (ISDN
BRI activity)
Flickering The ISDN BRI WAN connection is transmitting and
receiving data normally.
Off The ISDN BRI WAN connection is not transmitting or
receiving data. Check the BRI cable connection.
ISDN BRI with integrated
NT1 module
ACT (ISDN
BRI activity)
Flickering The ISDN BRI (with integrated NT1) WAN
connection is transmitting and receiving data
normally.
NT1 On The router detects the ISDN link integrity signal at the
U interface3and the internal S/T interface4, indicating
that an ISDN connection has been established.
Chassis/Module LED State Description

Troubleshooting the Cisco 2524 and Cisco 2525 Routers B-3
Running Diagnostic Tests
Running Diagnostic Tests
If you have the fractional T1/T1 module, you can use external test equipment with the
monitor jack labeled OUT to monitor signals coming into the RJ-48C port, without
interrupting normal data transmission. You can use the monitor jack labeled IN to inject
data, which would interrupt normal data transmission.
Getting Help
For information on technical support, onsite service, and exchange and repair services, refer
to the Cisco Information Packet publication that shipped with your router.
ISDN BRI with integrated
NT1 module
Blinking
once per
second
The ISDN connection at the U interface is up, and the
internal S/T interface is coming up. If this state
persists, the ISDN port is either not configured or it is
configured incorrectly.
Blinking
eight times
per second
The ISDN connection at the U interface is coming up.
Off The router is not detecting the ISDN link integrity
signal. An ISDN connection has not been established.
Check the BRI cable connection.
1. The Token Ring activity LED is labelled ACT.
2. The Ethernet link LED is for the Ethernet 10BaseT port only; it does not work with the Ethernet AUI port.
3. The U interface is from the wall jack (telco interface) to the NT1 device.
4. The S/T interface is from the ISDN port on the module to the microprocessor.
Chassis/Module LED State Description

B-4 Cisco 2524 and Cisco 2525 Router User Guide
Getting Help