Cisco Router 800 Series Software Configuration Guide
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9-9 Cisco 800 Series Software Configuration Guide 78-5372-06 Chapter 9 Troubleshooting ATM Troubleshooting Commands show atm interface Command To display ATM-specific information about an ATM interface, use the show atm interface atm0 privileged EXEC command. Following is the command syntax: show atm interface atm0 The following is an example of output from the show interface atm command: tw_820#sh atm int atm 0 Interface ATM0: AAL enabled: AAL5 , Maximum VCs:11, Current VCCs:0 Maximum Transmit Channels:0 Max. Datagram Size:1528 PLIM Type:INVALID - 640Kbps, Framing is INVALID, DS3 lbo:short, TX clocking:LINE 0 input, 0 output, 0 IN fast, 0 OUT fast Ethernet0 is up, line protocol is up Other possible messages: Ethernet0 is up, line protocol is down Ethernet0 is administratively down, line protocol is down The Ethernet interface is connected to the network and operating correctly. The Ethernet interface has been correctly configured and enabled, but the Ethernet cable might be disconnected from the LAN. The Ethernet interface has been disabled with the shutdown command, and the interface is disconnected. Dialer1 is up, line protocol is up Another possible message: Dialer1 is down, line protocol is down Dialer1 is up and operating correctly. Dialer1 is not operating, possibly because the interface has been brought down with the shutdown command or the ADSL cable is disconnected. Dialer1 is down, line protocol is down This is a standard message and does not indicate anything wrong with the configuration Table 9-2 show interface Command Output Description (continued) Output Description
Chapter 9 Troubleshooting ATM Troubleshooting Commands 9-10 Cisco 800 Series Software Configuration Guide 78-5372-06 Avail bw = 640 Config. is ACTIVE Ta b l e 9 - 3 describes the fields shown in the command output. debug atm Commands This section describes how to use the debug atm commands with additional keywords to troubleshoot the router. Before Using Debug Commands You can use the debug commands to troubleshoot configuration problems that you might be having on your network. Debug commands provide extensive, informative displays to help you interpret any possible problems. All debug commands are entered in privileged EXEC mode, and most debug commands take no arguments. Read the information in Ta b l e 9 - 4 before using debug commands. Table 9-3 show atm interface Command Output Description Field Description ATM interface Interface number. Always 0 for the Cisco 827 routers. AAL enabled Type of AAL enabled. The Cisco 827 routers support AAL5. Maximum VCs Maximum number of virtual connections this interface supports. Current VCCs Number of active virtual channel connections (VCCs). Maximum Transmit ChannelsMaximum number of transmit channels. Max Datagram SizeThe configured maximum number of bytes in the largest datagram. PLIM Type Physical layer interface module (PLIM) type
9-11 Cisco 800 Series Software Configuration Guide 78-5372-06 Chapter 9 Troubleshooting ATM Troubleshooting Commands CautionDebugging is assigned a high priority in your router CPU process, and it can render your router unusable. For this reason, use debug commands only to troubleshoot specific problems. The best time to use debug commands is during periods of low network traffic so that other activity on the network is not adversely affected. debug atm errors Command Use the debug atm errors command to display ATM errors. The no form of this command disables debugging output. Following is the command syntax: debug atm errors no debug atm errors Following is sample debug atm errors output. 820-uut2#deb atm err ATM errors debugging is on Router# 01:32:02:ATM(ATM0.2):VC(3) Bad SAP received 4500 01:32:04:ATM(ATM0.2):VC(3) Bad SAP received 4500 01:32:06:ATM(ATM0.2):VC(3) Bad SAP received 4500 01:32:08:ATM(ATM0.2):VC(3) Bad SAP received 4500 01:32:10:ATM(ATM0.2):VC(3) Bad SAP received 4500 Table 9-4 Important Information About Debug Commands Additional documentation You can find additional information and documentation about the debug commands in the Debug Command Reference document on the Cisco IOS software documentation CD-ROM that came with your router. If you are not sure where to find this document on the CD-ROM, use the Search function in the Verity Mosaic browser that comes with the CD-ROM. Disabling debugging To turn off any debugging, enter the undebug all command. Viewing debug message To view debug messages on the console, enter the logging console debug command. Telnet sessions If you want to use debug commands during a Telnet session with your router, you must first enter the terminal monitor command.
Chapter 9 Troubleshooting ATM Troubleshooting Commands 9-12 Cisco 800 Series Software Configuration Guide 78-5372-06 debug atm events Command Use the debug atm events command to display ATM events. The no form of this command disables debugging output. Following is the command syntax: debug atm events no debug atm events This command displays ATM events that occur on the ATM interface processor and is useful for diagnosing problems in an ATM network. It provides an overall picture of the stability of the network. If the interface is successfully communication with the DSLAM at the telephone company, the modem state is 0x10. If the interface is not communicating with the DSLAM, the modem state is 0x8. The following output indicates that the ADSL line is up (training successful): 00:02:57: DSL: Send ADSL_OPEN command. 00:02:57: DSL: Using subfunction 0xA 00:02:57: DSL: Using subfunction 0xA 00:02:57: DSL: Sent command 0x5 00:02:57: DSL: Received response: 0x26 00:02:57: DSL: Unexpected response 0x26 00:02:57: DSL: Send ADSL_OPEN command. 00:02:57: DSL: Using subfunction 0xA 00:02:57: DSL: Using subfunction 0xA 00:02:57: DSL: Sent command 0x5 00:03:00: DSL: 1: Modem state = 0x8 00:03:02: DSL: 2: Modem state = 0x10 00:03:05: DSL: 3: Modem state = 0x10 00:03:07: DSL: 4: Modem state = 0x10 00:03:09: DSL: Received response: 0x24 00:03:09: DSL: Showtime! 00:03:09: DSL: Sent command 0x11 00:03:09: DSL: Received response: 0x61 00:03:09: DSL: Read firmware revision 0x1A04 00:03:09: DSL: Sent command 0x31 00:03:09: DSL: Received response: 0x12 00:03:09: DSL: operation mode 0x0001 00:03:09: DSL: SM: [DMTDSL_DO_OPEN -> DMTDSL_SHOWTIME] In case of failure, you may see the modem state remain at 0x8 and not move to 0x10: 00:02:57: DSL: Send ADSL_OPEN command. 00:02:57: DSL: Using subfunction 0xA 00:02:57: DSL: Using subfunction 0xA
9-13 Cisco 800 Series Software Configuration Guide 78-5372-06 Chapter 9 Troubleshooting ATM Troubleshooting Commands 00:02:57: DSL: Sent command 0x5 00:02:57: DSL: Received response: 0x26 00:02:57: DSL: Unexpected response 0x26 00:02:57: DSL: Send ADSL_OPEN command. 00:02:57: DSL: Using subfunction 0xA 00:02:57: DSL: Using subfunction 0xA 00:02:57: DSL: Sent command 0x5 00:03:00: DSL: 1: Modem state = 0x8 00:03:00: DSL: 1: Modem state = 0x8 00:03:00: DSL: 1: Modem state = 0x8 00:03:00: DSL: 1: Modem state = 0x8 00:03:00: DSL: 1: Modem state = 0x8 00:03:00: DSL: 1: Modem state = 0x8 debug atm packet Command Use the debug atm packet command to display per-packet debugging output. The output reports information online when a packet is received or a transmission is attempted. The no form of this command disables debugging output. Following is the command syntax: debug atm packet [interface atm number [vcd vcd-number][vc vpi/vci number]] no debug atm packet [interface atm number [vcd vcd-number][vc vpi/vci number]] Following are the keywords used in this command: The debug atm packet command displays all process-level ATM packets for both outbound and inbound packets. This command is useful for determining whether packets are being received and transmitted correctly. CautionBecause the debug atm packet command generates a significant amount of output for every packet processed, use it only when network traffic is low so that other system activities are not adversely affected. interface atm number(Optional) ATM interface or subinterface number. vcd vcd-number(Optional) Number of the virtual circuit designator (VCD). vc vpi/vci number(Required) The vpi/vci value of the ATM PVC.
Chapter 9 Troubleshooting ATM Troubleshooting Commands 9-14 Cisco 800 Series Software Configuration Guide 78-5372-06 Below is sample debug atm packet output. Router# 01:23:48:ATM0(O): VCD:0x1 VPI:0x1 VCI:0x64 DM:0x0 SAP:AAAA CTL:03 OUI:000000 TYPE:0800 Length:0x70 01:23:48:4500 0064 0008 0000 FF01 9F80 0E00 0010 0E00 0001 0800 A103 0AF3 17F7 0000 01:23:48:0000 004C BA10 ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD 01:23:48:ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD 01:23:48:ABCD ABCD ABCD ABCD ABCD 01:23:48: 01:23:48:ATM0(I): VCD:0x1 VPI:0x1 VCI:0x64 Type:0x0 SAP:AAAA CTL:03 OUI:000000 TYPE:0800 Length:0x70 01:23:48:4500 0064 0008 0000 FE01 A080 0E00 0001 0E00 0010 0000 A903 0AF3 17F7 0000 01:23:48:0000 004C BA10 ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD 01:23:48:ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD ABCD 01:23:48:ABCD ABCD ABCD ABCD ABCD 01:23:48: Ta b l e 9 - 5 describes the fields shown in the debug atm packet command output. Table 9-5 debug atm packet Command Output Description Field Description ATM0 Interface that is generating the packet. (O) Output packet. (I) would mean receive packet. Pak size Packet size in bytes. VCD: 0xnVirtual circuit associated with this packet, where n is some value. VPI: 0xnVirtual path identifier for this packet, where n is some value. DM: 0xnDescriptor mode bits, where n is some value. MUXETYPE: nMultiplex type. Length: nTotal length of the packet (in bytes) including the ATM header(s).
9-15 Cisco 800 Series Software Configuration Guide 78-5372-06 Chapter 9 Troubleshooting Troubleshooting Telephone Interfaces Troubleshooting Telephone Interfaces Ta b l e 9 - 6 describes possible problems that your router might be experiencing and solutions for solving the problems. Ta b l e 9 - 7 describes the applicable debug commands. Table 9-6 Symptoms of Telephone Interfaces Trouble Symptom Possible Problem Solution Even though you have devices connected to ports 1 and 2, all calls are going to port 1.You have not created dial peers.Create dial peers. You cannot make outgoing calls.You have not specified all ISDN directory numbers with a SPID (North America only). Check the settings of the isdn spid 1 and isdn spid 2 commands to make sure that you have specified all ISDN directory numbers for each SPID. Even though you have created dial peers and set up distinctive ringing and ISDN voice priority, calls meant for secondary or tertiary ISDN directory numbers are routed to the primary number.Incorrect dial peer, distinctive ringing, or ISDN voice priority configurations. Check dial peer, distinctive ringing, or ISDN voice priority configurations Use the debug q931 command.
Chapter 9 Troubleshooting Troubleshooting Serial Line Problems 9-16 Cisco 800 Series Software Configuration Guide 78-5372-06 Troubleshooting Serial Line Problems This section describes how to troubleshoot problems in the following areas: Synchronous channel service unit/data service unit (CSU/DSU) clocking Synchronous leased lines Asynchronous dial-up lines Frame Relay X.25 Synchronous CSU/DSU Clocking Problems Clocking conflicts in serial connections can lead to either chronic loss of connection service or to degraded performance. This section describes how to detect and solve clocking problems with synchronous CSU/DSUs. Table 9-7 Troubleshooting Telephone Interface Command Possible Problem Solution debug pots driver [1 | 2] (privileged EXEC mode)Caller ID device is not working either because you have not ordered the feature or because your device is not supported.Contact your telephone service provider to verify that you ordered caller ID or to determine if there is a problem with the feature. debug pots csm [1 | 2] (privileged EXEC mode)One of your dial peers might contain an invalid destination.Check the settings of the destination pattern in each dial peer. If a setting is incorrect, use the destination-pattern ldn command.
9-17 Cisco 800 Series Software Configuration Guide 78-5372-06 Chapter 9 Troubleshooting Troubleshooting Serial Line Problems Detecting Problems Use the following steps to detect clocking conflicts on your serial interface: Step 1Enter the show interfaces serial 0 privileged EXEC command on the routers at both ends of the link. Step 2Examine the output for cyclic redundancy check (CRC) or framing errors and aborts. If the number of CRC or framing errors exceeds an approximate range of 0.5 to 2.0 percent of traffic on the serial interface, clocking problems are likely to exist somewhere in the WAN. Step 3Isolate the source of the clocking conflicts by performing a series of ping tests and loopback tests (both local and remote). Step 4Reenter the show interfaces serial 0 privileged EXEC command on the routers at both ends of the link. Determine if CRC and framing errors are increasing and if so, where they are accumulating. If input errors are accumulating on both ends of the connection, clocking of the CSU is the likely problem. If input errors are accumulating on one end of the connection, clocking of the DSU or cabling are the likely problems. If aborts are occurring on one end of the connection, the other end could be sending bad information or there could be a problem with the serial line.
Chapter 9 Troubleshooting Troubleshooting Serial Line Problems 9-18 Cisco 800 Series Software Configuration Guide 78-5372-06 Ta b l e 9 - 8 describes possible CSU/DSU clocking problems your router might be experiencing and the solutions for solving those problems. Table 9-8 Synchronous CSU/DSU Clocking Problems Symptom Solution Incorrect CSU configuration Perform the following tasks in the following order: Determine whether the CSUs at both ends of the serial line agree on the clock source (local or line). If the CSUs do not agree, configure them to do so. Check the line build out (LBO) setting on the CSU to ensure that the impedance matches that of the physical line. For information on configuring your CSU, refer to your CSU documentation. Incorrect DSU configuration Perform the following steps in the following order: Determine whether the DSUs at both ends of the serial line have serial clock transmit external (SCTE) mode enabled. If SCTE is not enabled on both ends of the connection, enable it. For any interface that is connected to a line of 128 kbps or faster, SCTE must be enabled. Make sure that ones density is maintained, which requires that the DSU use the same framing and coding schemes (for example, Extended Superframe Format [ESF] and Binary 8-Zero Substitution [B8ZS]) that are used by the leased line or other carrier service. Check with your leased line provider for information on its framing and coding schemes. If your carrier service uses Alternate Mark Inversion (AMI) coding, either invert the transmit clock on both sides of the link or run the DSU in bit-stuff mode. For information on configuring your DSU, refer to your DSU documentation.