Before troubleshooting a software problem, you must connect a terminal or PC to the router by using the light-blue console port. With a connected terminal or PC, you can view status messages from the router and enter commands to troubleshoot a problem.

You can also remotely access the interface (Ethernet, ADSL, or telephone) by using Telnet. The Telnet option assumes that the interface is up and running.

If you cannot locate the source of a problem, contact your local reseller for advice. Before you call, you should have the following information ready:

• Chassis type and serial number
• Maintenance agreement or warranty information
• Type of software and version number
• Date you received the hardware
• Brief description of the problem
• Brief description of the steps you have taken to isolate the problem

If you experience trouble with the ADSL connection, verify the following:

• The ADSL line is connected and is using pins 3 and 4. For more information on the ADSL connection, see the hardware guide for your router.
• The ADSL CD LED is on. If it is not on, the router may not be connected to the DSL access multiplexer (DSLAM). For more information on the ADSL LEDs, see the hardware installation guide specific for your router.
• The correct Asynchronous Transfer Mode (ATM) virtual path identifier/virtual circuit identifier (VPI/VCI) is being used.
• The DSLAM supports discrete multi-tone (DMT) Issue 2.
• The ADSL cable that you connect to the Cisco router must be 10BASE-T Category 5, unshielded twisted-pair (UTP) cable. Using regular telephone cable can introduce line errors.

Symmetrical high-data-rate digital subscriber line (SHDSL) is available on the Cisco 888 routers. If you experience trouble with the SHDSL connection, verify the following:

• The SHDSL line is connected and using pins 3 and 4. For more information on the G.SHDSL connection, see the hardware guide for your router.
• The G.SHDSL LED is on. If it is not on, the router may not be connected to the DSL access multiplexer (DSLAM). For more information on the G.SHDSL LED, see the hardware installation guide specific for your router.
• The correct asynchronous transfer mode (ATM) virtual path identifier/virtual circuit identifier (VPI/VCI) is being used.
• The DSLAM supports the G.SHDSL signaling protocol.

Use the show controllers dsl 0 command in EXEC mode to view an SHDSL configuration.

Very-high-data-rate digital subscriber line 2 (VDSL2) is available on the Cisco 887 routers. If you experience trouble with the VDSL2 connection, verify the following:

• The VDSL2 line is connected and using pins 3 and 4. For more information on the VDSL2 connection, see the hardware guide for your router.
• The VDSL2 LED CD light is on. If it is not on, the router may not be connected to the DSL access multiplexer (DSLAM). For more information on the VDSL2 LED, see the hardware installation guide specific for your router.
• The DSLAM supports the VDSL2 signaling protocol.

Use the show controllers vdsl 0 command in EXEC mode to view a VDSL2 configuration. The debug vdsl 0 daemon state command can be used to enable the debug messages that print the state transition of VDSL2 training.

If there is trouble with the VDSL firmware file, you can reload or upgrade it without upgrading your Cisco IOS image. Use the command:

controller vdsl 0 firmware flash:<firmware file name>

to load the firmware file into the VDSL modem chipset. Then enter shutdown/no shutdown commands on the controller vdsl 0 interface. After this, the new firmware will be downloaded and the VDSL2 line starts training up.

Note	Cisco 860VAE series ISRs require that the router be reloaded (IOS reload) before the new VDSL firmware will be loaded.

If the command is not present or the named firmware file is corrupt or not available, the default firmware file flash:vdsl.bin is checked to be present and not corrupt. The firmware in this file is then downloaded to the modem chipset.

Note	Cisco 860VAE series ISRs will state the reason of failure during bootup if the new VDSL firmware fails to load after IOS reload.

Use the show interfaces command to display the status of all physical ports (Ethernet, Fast Ethernet, and ATM) and logical interfaces on the router. Table 1describes messages in the command output.

The following example shows how to view the status of Ethernet or Fast Ethernet Interfaces:

Router# show interfaces ethernet 0 **similar output for show interfaces fastethernet 0 command **
Ethernet0 is up, line protocol is up 
Hardware is PQUICC Ethernet, address is 0000.Oc13.a4db 
(bia0010.9181.1281)
Internet address is 170.1.4.101/24
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, 
	reliability 255/255., txload 1/255, rxload 1/255
	Encapsulation ARPA, loopback not set
	Keepalive set (10 sec)

The following example shows how to view the status of ATM Interfaces:

Router# show interfaces atm 0
ATM0 is up, line protocol is up 
  Hardware is PQUICC_SAR (with Alcatel ADSL Module)
  Internet address is 14.0.0.16/8
  MTU 1500 bytes, sub MTU 1500, BW 640 Kbit, DLY 80 usec, 
     reliability 40/255, txload 1/255, rxload 1/255
  Encapsulation ATM, loopback not set
  Keepalive not supported 
  Encapsulation(s):AAL5, PVC mode
  10 maximum active VCs, 1 current VCCs
  VC idle disconnect time:300 seconds
  Last input 01:16:31, output 01:16:31, output hang never
  Last clearing of "show interface" counters never
  Input queue:0/75/0 (size/max/drops); Total output drops:0
  Queueing strategy:Per VC Queueing
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     512 packets input, 59780 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 1024 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     426 packets output, 46282 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets
     0 output buffer failures, 0 output buffers swapped out

The following example shows how to view the status of Dialer Interfaces:

Router# show interfaces dialer 1
Dialer 1 is up, line protocol is up 
	Hardware is Dialer interface
	Internet address is 1.1.1.1/24
	MTU 1500 bytes, BW 100000 Kbit, DLY 100000 usec, reliability
		255/255. txload 1/255, rxload 1/255
	Encapsulation PPP, loopback not set
	Keepalive set (10 sec)
DTR is pulsed for 5 seconds on reset
LCP Closed

The table below describes possible command output for the show interfaces command.

Use the following commands to troubleshoot your ATM interface:

Several methods are available for upgrading software on the Cisco 860 and Cisco 880 series Integrated Services Routers, including:

• Copy the new software image to flash memory over the LAN or WAN while the existing Cisco IOS software image is operating.
• Copy the new software image to flash memory over the LAN while the boot image (ROM monitor) is operating.
• Copy the new software image over the console port while in ROM monitor mode.
• From ROM monitor mode, boot the router from a software image that is loaded on a TFTP server. To use this method, the TFTP server must be on the same LAN as the router.

To recover a lost enable or lost enable-secret password:

1. Change the Configuration Register
2. Reset the Router
3. Reset the Password and Save Your Changes (for lost enable secret passwords only)
4. Reset the Configuration Register Value

Note	Recovering a lost password is only possible when you are connected to the router through the console port. These procedures cannot be performed through a Telnet session.

Tip	See the “Hot Tips” section on Cisco.com for additional information on replacing enable secret passwords.

This feature enables faster SIM switching between the SIMs in slot 0 and slot 1, if the carriers corresponding to both the SIM cards use the same firmware.

Router# config t
Router(config)# Controller Cellular Cellular Interface Number
Router(config-controller)# lte sim fast-switchover enable

Router(config-controller)# no lte sim fast-switchover enable

Router(config-controller)# lte sim ?
authenticate CHV1 authentication
data-profile Data Profile number
fast-switchover Fast sim switchover
max-retry Maximum SIM switchovers
primary Controller's primary SIM

Router(config-controller)# lte sim fast-switchover ?
enable Enable fast sim switchover

Router# sh run |sec cont
controller Cellular 0
lte sim fast-switchover enable

Router(config-controller)# no lte sim fast-switchover ?
enable Enable fast sim switchover

Router#sh cont cel 0 | inc Sim
SIM fastswitchover is ON

Router#sh cont cel 0 | inc Sim
SIM fastswitchover is OFF

After you connect the cables and power up the router, we recommend that you use the Cisco CP Express web-based application to configure the initial router settings.

For instructions on how to use Cisco CP Express to configure the router see the Cisco CP Express User’s Guide .