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Cisco Routers - Troubleshooting

Routing with Cisco 700 Series for LAN-ISDN Service

Power-On Self-Test

When the router is powered on, it performs a series of self-tests. After these tests are completed, the LEDs indicate operating status. Any operational problem is represented by a combination of lit and unlit LEDs. 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.

LED Diagnostics

RDY	NT1	LINE	CH1	CH2	Test Result
On	Blinks several times a second	Off	Off	Off	Internal NT1 is unable to synchronize with the ISDN switch.
On	Blinks once a second	Off	Off	Off	Internal NT1 is synchronized with the ISDN switch, but is unable to synchronize with the ISDN terminal devices.
Off	Off	On	Off	Off	Waiting for software.
On	Off	On	On	On	Processor inactive.
Off	Off	Off	Off	Off	Processor self-test error.
Off	Off	Off	Off	On	EPROM ¹ checksum error.
Off	Off	Off	On	Off	RAM error.
Off	Off	Off	On	On	Flash memory error.
Off	Off	On	Off	On	HDLC ² packet chip error.
Off	Off	On	On	Off	Configuration port error.
Off	Off	On	On	On	ISDN interface chip error.

¹EPROM: erasable programmable read-only memory.
²HDLC: High-Level Data Link Control.

TWAIT Timer

During initialization (power-up or reboot), with the switch type set to NI1, the followingmessage 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.

Communicating with the WAN

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:

The wrong ISDN switch type was set. Change the switch type by using the set switch command or the Cisco 700 Fast Step Setup application.
The ISDN line was incorrectly configured by the ISDN service provider. Confirm the line configuration with the ISDN service provider.
The SPIDs were not entered or were entered incorrectly. Enter or change the SPIDs by using the set spid command or the Cisco 700 Fast Step Setup application.

Outgoing Calls Cannot be Initiated

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

A telephone number was incorrectly configured with the set number command.
To resolve error messages such as "Incompatible Destination," use the set number command to enter a 1 at the beginning of the number, even if the number called is in the same area code. (Some networks require the 1 to connect a data call at 64 kbps.)
The number called is busy. Try the call again.
The ISDN line was incorrectly configured by the ISDN service provider. Confirm the line configuration with the ISDN service provider.
If using authentication, the client password or secret might not match the remote router's host password or secret.

Incoming Calls Not Received

If the router places outbound calls without any problems, but cannot receive incoming calls, check the following:

Verify the directory numbers are set correctly. Enter or change the number with the set directory number command or the Cisco 700 Fast Step Setup application.
ISDN line provisioning is correct. Confirm the line configuration with the ISDN service provider.
PPP host secret and password match the client secret and password. Confirm the passwords with the ISDN service provider.
A profile with a name matching the client host name exists. Rename or delete the profile.

Router Calls Itself

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.

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.

Communicating with the LAN

If you have problems communicating with a 10BaseT Ethernet LAN device (such as your PC), do the following:

Verify the LINK LED on the back panel of all models except Cisco 766 or Cisco 776 routers or at least one of the link (LK1, LK2, LK3, or LK4) LEDs on Cisco 766 or Cisco 776 routers is on, indicating the router is communicating with the LAN device. If the LED is blinking, it is attempting to establish a connection. Check the Ethernet cables or the device attached to the other end of the cable, such as the network interface card (NIC) in your PC.
Verify the LAN LED on the front panel is lit, indicating the router is communicating with the LAN device. If the LED is blinking, it is attempting to establish a connection. Check the Ethernet cables or the device attached to the other end of the cable, such as the NIC in your PC.
Check the HUB/NODE switch located on the back panel of all models except Cisco 766 or Cisco 776 routers. This switch eliminates the need for an Ethernet crossover cable when connecting to a hub. If it is in the wrong position, it will not cause any damage to the equipment; however, the signals will not be sent to the correct location. If you are connecting directly to a PC, the switch should be in the HUB position. If you are connecting to a hub, the switch should be in the NODE position. For more information on Hub/Node connections, click here.

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.

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.

The table below lists the ISDN BRI cause values, the hexadecimal translation, the cause message, and a short definition of the cause message. Cause values are standardized; however, each ISDN service provider uses its own version of the cause message wording. Therefore, the cause messages shown below might not match the messages exactly as they appear on the terminal.

Cause Value¹	Hex Value²	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 CCITT ³ 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.

¹Cause value is shown in decimal format.
²Hex value = hexadecimal translation of the decimal cause value.
³CCITT = Consultative Committee for International Telegraph and Telephone.