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Troubleshooting Cisco 700 Series Routers

Troubleshooting Cisco 700 Series Routers

This chapter will help you find solutions, should you be having problems with your router. Begin by attempting to isolate the problem to a specific source.

The following sections describe troubleshooting particular kinds of problems:

Figure 5-1 and Figure 5-2 illustrate the LEDs on the front panels of Cisco 700 series routers. See the section, "Front Panel LED Functions," later in this chapter for a detailed description of the LEDs.


Figure 5-1: Cisco 760 Series LEDs (Cisco 766 Shown)

Note The Cisco 761 and Cisco 765 routers do not have NT-1 LEDs. The Cisco 761 and Cisco 762 routers do not have PH1 and PH2 LEDs.

Figure 5-2: Cisco 770 Series LEDs (Cisco 776 Shown)

Note Cisco 771 and Cisco 775 routers do not have an NT-1 LED. Cisco 771 and Cisco 772 routers do not have PH1 and PH2 LEDs.

Front Panel LED Functions

The LEDs on the front panel of Cisco 700 series routers display the activity status of the router as connections are made and as packets are sent and received.

Table 5-1 lists the LEDs and their functions.


Table  5-1: Front Panel LED Functions
LED Function
RD (Cisco 760 Series)
RDY (Cisco 770 Series) 		Indicates the router operating status. On when power is supplied to the router, the router passes the self-test and is operating normally.
NT-1
(Cisco 762, Cisco 766, Cisco 772, and Cisco 776 only)

  • On (unblinking) indicates that the internal NT-1 and the ISDN switch have synchronized over the ISDN line.

  • Blinking (5 blinks per second) indicates that the internal NT-1 is attempting to synchronize with the telephone switch.

  • Blinking (1 blink per second) indicates that the internal NT-1 is attempting to synchronize with the ISDN terminal devices.

LINE

 On (unblinking) indicates synchronization between the NT-1 S interface and the ISDN terminal device(s). Also indicates framing between the router and the ISDN switch.
LAN On when packets have been sent to or received from the Ethernet within the last minute.
LAN RXD Blinks when packets are received from the Ethernet.
LAN TXD Blinks when packets are sent to the Ethernet.
LK1 (770 only) On when there is a connection on the first link. Blinks (1 blink per 1.5 seconds) when there is a problem on the first link.
LK2 (770 only) On when there is a connection on the second link. Blinks (1 blink per 1.5 seconds) when there is a problem on the second link.
LK3 (770 only) On when there is a connection on the third link. Blinks (1 blink per 1.5 seconds) when there is a problem on the third link.
LK4 (770 only) On when there is a connection on the fourth link. Blinks (1 blink per 1.5 seconds) when there is a problem on the fourth link.
CH1 Blinks when a call is connected on the first ISDN B channel. After the call is established, the LED remains on without blinking.
CH1 RXD Blinks when packets are received from the first ISDN B channel.
CH1 TXD Blinks when packets are sent on the first ISDN B channel.
CH2 Blinks when a call is being connected on the second ISDN B channel. When the call is established, the LED remains on without blinking.
CH2 RXD Blinks when packets are received from the second ISDN B channel.
CH2 TXD Blinks when packets are sent on the second ISDN B channel.
PH 1
PH 2
(Cisco 765, Cisco 766, Cisco 775, and Cisco 776 only)

  • Blinks when the corresponding basic telephone service line is off-hook.

  • Blinks in the following patterns when entering DTMF commands for the corresponding basic telephone service port on the router:

    • Blinks on and off twice per second for 2 seconds if the command is entered correctly.

    • Blinks on and off once per second for 4 seconds if the command is entered incorrectly.

Rear Panel LED Function

There is one LED on the rear panel, the LINK LED. The LINK LED remains lit when the router is

LED Diagnostics

The front panel LEDs can be used for diagnostic purposes. When the router is powered on, it performs a series of self-tests. After these tests are completed, any operational problem is represented by a combination of lit and unlit LEDs.

Table 5-2 lists the combinations of lit and unlit LEDs and their significance.


Table  5-2: LED Error Messages
RDY NT-1 LINE CH1 CH2 Test Result
On Blinking several times per second See Note1 Internal NT-1 is unable to synchronize with the ISDN switch
On Blinking one time per second Internal NT-1 is synchronized with the ISDN switch, but is unable to synchronize with the ISDN terminal devices
On Waiting for software
On On On On Processor inactive
Processor self-test error
On EPROM2 checksum error
On RAM error
On On Flash memory error
On On HDLC3 packet chip error
On On Configuration port error
On On On ISDN interface chip error

1 Note: A blank cell indicates that the LED is not on.
2 EPROM = erasable programmable read-only memory.
3 HDLC = High-Level Data Link Control.

Power-On

Cisco 760 series routers have 12 to 14 (depending on the model) LEDs on the front panel. Cisco 770 series routers have 15 to 18 LEDs on the front panel. In addition to indicating operating status, LEDs indicate problems that might occur during the power-on process.

TWAIT Timer

During initialization (power-up or reboot), with the switch type set to NI-1, the following message displays:

host> Please wait for TWAIT timer to expire in __ seconds
host> Make a call to bypass this timer

The timer value varies from 1 second to 5 minutes. Upon expiration of the time, the router requests a terminal endpoint identifier (TEI) and initiates SPID initialization as usual. If needed, either a voice or data call can be initiated instead of waiting for the timer to expire. This stops the timer immediately and allows initialization to continue.

Note that the call will be successful unless the ISDN line has not been given enough time to rest before power-up or reboot.

Inband Timeout Violation

The Inband Timeout Violation error message indicates the router cannot communicate with the remote device after an ISDN connection had been established. This might be caused by the speed of the connection. Under some conditions, the router attempts to connect at 56 kbps and the remote device attempts to connect at 64 kbps. The data becomes unusable. Set the speed to 64 kbps, and attempt the connection again.

Configuration Problems

The following conditions are often caused by router configuration problems:

Router Calls Itself

If the router calls itself, check that the number configured with the set number command is not the same as the number configured with the set directory number command.

ISDN supports two separate logical data channels on the same physical line. If these two numbers are the same, the router might attempt to call itself when on-demand dialing is enabled or if the user issues the call command.

Terminal Identifier or SPID Problems

Either of the following messages received on your terminal might indicate a SPID configuration problem:

Channel Not Available
Facility Not Subscribed

Check for the following conditions:

Outgoing Calls Cannot be Initiated

If outgoing calls are unsuccessful, check for the following conditions:

You can also try initiating the call manually.

Outgoing Calls are Rejected

If an outgoing call is initially successful and then rejected, check for the following conditions:

Incoming Calls Not Received

The router places outbound calls without any problems, but cannot receive incoming calls. Verify the following conditions are met:

10BaseT Connectivity Problems

If you have problems connecting to the 10BaseT Ethernet network, check the node/hub configuration. On Cisco 760 or 770 series routers, this configuration is set with a switch on the rear panel labeled HUB/NODE.

Software Loading Errors

If an error occurs during a software download, a combination of blinking LEDs indicates a problem. An error code is also displayed on the terminal.

Table 5-3 lists the combination of blinking LEDs that indicate an error, along with the error code and a description of the error.


Table  5-3: LED Error Messages--Software Download
Blinking LED Error Code Description of Error
Line

CH 2

 E-1 A framing, parity, or overflow error occurred during software download, usually because of an incorrect data rate or configuration port setting. Check the data rate and configuration port settings.
CH 1 E-2 A colon was not at the beginning of a line in the new software image file. Either the software image file is corrupted or some characters were entered before the download started. Start the software load process again. If the same error occurs, replace the software image file.
Line

CH 1

 E-3 One line in the software image file has a bad checksum, usually because of a temporary line error. Start the software download process again.
Line

CH 1

CH 2

 E-5 The software image file has a bad or missing checksum. Start the software load process again. If the same error occurs, replace the software image file.

ISDN BRI Cause Values

This section describes ISDN BRI standard cause values that might be received from the ISDN switch when using Cisco 700 series routers. These values are sent from the ISDN switch to the router to indicate ISDN call status.

Although ISDN service providers generally define cause messages with decimal values, Cisco 700 series routers display the hexadecimal (or hex) translation of the decimal value.

Note Cause values are standardized; however, each ISDN service provider uses its own version of the cause message wording. Therefore, the cause messages shown in Table 5-4 might not match the messages exactly as they appear on the terminal.

Table 5-4 lists the ISDN BRI cause values, the hexadecimal translation, the cause message, and a short definition of the cause message.


Table  5-4: ISDN BRI Cause Values and Cause Messages
Cause Value1 Hex Value1 Cause Message Definition
1 0001 Unassigned number The ISDN number was sent to the switch in the correct format; however, the number is not assigned to any destination equipment.
2 0002 No route to specified transit network The ISDN exchange is asked to route the call through an unrecognized intermediate network.
3 0003 No route to destination The call was routed through an intermediate network that does not serve the destination address.
6 0006 Channel unacceptable The service quality of the specified channel is insufficient to accept the connection.
7 0007 Call awarded and delivered The user is assigned an incoming call that is connected to a channel with an established call.
16 0010 Normal call clearing Normal call clearing has occurred.
17 0011 User busy The called system acknowledges the connection request, but is unable to accept the call because all B channels are in use.
18 0012 No user responding The connection cannot be completed because the destination does not respond to the call.
19 0013 No answer from user (user alerted) The destination responds to the connection request, but fails to complete the connection within the prescribed time. The problem is at the remote end of the connection.
21 0015 Call rejected The destination is capable of accepting the call, but rejected the call for an unknown reason.
22 0016 Number changed The ISDN number used to set up the call is not assigned to any system. (If an alternate address is assigned to the called equipment, it might be returned in the diagnostic field of this message.)
26 001A Non-selected user clearing The destination is capable of accepting the call, but rejected the call because it was not assigned to the user.
27 001B Destination out of order The destination cannot be reached because the interface is not functioning correctly, and a signaling message cannot be delivered. This might be a temporary condition, but could last for an extended period of time. For example, the remote equipment might be turned off.
28 001C Invalid number format The connection could be established because the destination address was presented in an unrecognizable format or because the destination address was incomplete.
29 001D Facility rejected The facility requested by the user cannot be provided by the network.
30 001E Response to STATUS ENQUIRY The status message was generated in direct response to the receipt of a status inquiry message.
31 001F Normal, unspecified Reports the occurrence of a normal event when no standard cause applies. No action required.
34 0022 No circuit/channel available The connection cannot be established because no appropriate channel is available to take the call.
38 0026 Network out of order The destination cannot be reached because the network is not functioning correctly, and the condition might last for an extended period of time. An immediate reconnect attempt will probably be unsuccessful.
41 0029 Temporary failure An error occurred because the network is not functioning correctly. The problem will be resolved shortly.
42 002A Switching equipment congestion The destination cannot be reached because the network switching equipment is temporarily overloaded.
43 002B Access information discarded The network cannot provide the requested access information.
44 002C Requested circuit/channel not available The remote equipment cannot provide the requested channel for an unknown reason. This might be a temporary problem.
47 002F Resource unavailable, unspecified The requested channel or service is unavailable for an unknown reason. This might be a temporary problem.
49 0031 Quality of service unavailable The requested quality of service (as defined by CCITT2 recommendation X.213) cannot be provided by the network. This might be a subscription problem.
50 0032 Requested facility not subscribed The remote equipment supports the requested supplementary service, but only by subscription.
57 0039 Bearer capability not authorized The user requested a bearer capability (BC) that the network provides, but that the user is not authorized to use. This might be a subscription problem.
58 003A Bearer capability not presently available The network normally provides the requested BC, but not at the present time. This might be due to a temporary network problem or to a subscription problem.
63 003F Service or option not available, unspecified The network or remote equipment was unable to provide the requested service option for an unspecified reason. This might be a subscription problem.
65 0041 Bearer capability not implemented The network cannot provide the bearer capability (BC) requested by the user.
66 0042 Channel type not implemented The network or the destination equipment does not support the requested channel type.
69 0045 Requested facility not implemented The remote equipment does not support the requested supplementary service.
70 0046 Only restricted digital information bearer is available The network is unable to provide unrestricted digital information BC.
79 004F Service or option not available, unspecified The network or remote equipment is unable to provide the requested service option for an unspecified reason. This might be a subscription problem.
81 0051 Invalid call reference value The remote equipment received a call with a call reference that is not currently in use on the user-network interface.
82 0052 Identified channel does not exist The receiving equipment is requested to use a channel that is not activated on the interface for calls.
83 0053 A suspended call exists but this call identity does not The network received a call resume request. The call resume request contained a Call Identify information element that indicates that the call identity is being used for a suspended call.
84 0054 Call identity in use The network received a call resume request. The call resume request contained a Call Identify information element that indicates that it is in use for a suspended call.
85 0055 No call suspended The network received a call resume request when there was not a suspended call pending. This might be a transient error that will be resolved by successive call retries.
86 0056 Call having requested call identity has been cleared The network received a call resume request. The call resume request contained a Call Identity information element, which once indicated a suspended call. However, the suspended call was cleared either by timeout or by the remote user.
88 0058 Incompatible destination Indicates that an attempt was made to connect to non-ISDN equipment, for example, to an analog line.
91 005B Invalid transit network specified The ISDN exchange was asked to route the call through an unrecognized intermediate network.
95 005F Invalid message, unspecified An invalid message was received, and no standard cause applies. This is usually due to a D-channel error. If this error occurs systematically, report it to your ISDN service provider.
96 0060 Mandatory information element is missing The receiving equipment received a message that did not include one of the mandatory information elements. This is usually due to a D-channel error. If this error occurs systematically, report it to your ISDN service provider.
97 0061 Message type non-existent or not implemented The receiving equipment received an unrecognized message, either because the message type was invalid or because the message type was valid but not supported. Cause 97 is due to either a problem with the remote configuration or a problem with the local D channel.
98 0062 Message incompatible with call state or message type non-existent The remote equipment received an invalid message, and no standard cause applies. Cause 98 is due to a D-channel error. If this error occurs systematically, report it to your ISDN service provider.
99 0063 Information element nonexistent or not implemented The remote equipment received a message that includes information elements, which were not recognized. This is usually due to a D-channel error. If this error occurs systematically, report it to your ISDN service provider.
100 0064 Invalid information element contents The remote equipment received a message that includes invalid information in the information element. This is usually due to a D-channel error.
101 0065 Message not compatible with call state The remote equipment received an unexpected message that does not correspond to the current state of the connection. This is usually due to a D-channel error.
102 0066 Recovery on timer expiry An error-handling (recovery) procedure was initiated by a timer expiration. This is usually a temporary problem.
111 006F Protocol error, unspecified An unspecified D-channel error when no other standard cause applies.
127 007F Interworking, unspecified An event occurred, but the network does not provide causes for the action that it takes. The precise problem is unknown.
UNKNOWN - Unknown or local error An event occurred, but the network does not provide causes for the action that it takes. The precise problem is unknown.

1 Hex value = hexadecimal translation of the decimal cause value.
2 CCITT = Consultative Committee for International Telegraph and Telephone.


1 Cause value is shown in decimal format.

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