Serial Wire Debug Specification

Troubleshooting Serial Lines Cisco Systems. Table Of Contents. Troubleshooting Serial Lines. Troubleshooting Using the show interfaces serial Command. Serial Lines show interfaces serial Status Line Conditions. Using this site ARM Forums and knowledge articles Most popular knowledge articles Frequently asked questions How do I navigate the site View and Download ADTRAN 1000R Series command reference manual online. ADTRAN Network Device Manual. R Series Network Card pdf manual download. Use the information in this chapter to configure serial interfaces. For information on configuring an ATM interface, refer to the Configuring ATM Access over a. Serial Lines Increasing Output Drops on Serial Link. Serial Lines Increasing Input Drops on Serial Link. Serial Lines Increasing Input Errors in Excess of 1 Percent of Total Interface Traffic. Serial Lines Troubleshooting Serial Line Input Errors. Serial Lines Increasing Interface Resets on Serial Link. Serial Lines Increasing Carrier Transitions Count on Serial Link. Using the show controllers Command. Using debug Commands. Using Extended ping Tests. Troubleshooting Clocking Problems. Clocking Overview. Clocking Problem Causes. R7692091-01.jpg' alt='Serial Wire Debug Specification' title='Serial Wire Debug Specification' />Detecting Clocking Problems. Isolating Clocking Problems. Clocking Problem Solutions. Inverting the Transmit Clock. Adjusting Buffers. Tuning System Buffers. Implementing Hold Queue Limits. Using Priority Queuing to Reduce Bottlenecks. Special Serial Line Tests. CSU and DSU Loopback Tests. CSU and DSU Local Loopback Tests for HDLC or PPP Links. CSU and DSU Remote Loopback Tests for HDLC or PPP Links. Detailed Information on the show interfaces serial Commandshow interfaces serial. Syntax Description. Command Mode. Usage Guidelines. Sample Displays. Troubleshooting T1 Problems. Troubleshooting Using the show controller t. Commandshow controller t. Conditions. Is the Controller Administratively Down Is the Line Up If Receiver Has Loss of Frame. If Receiver Has Loss of Signal. If the Line Is in Loopback Mode. If the Controller Displays Any Alarms. Receive RX Alarm Indication Signal AIS BlueReceive Rx Remote Alarm Indication YellowTransmitter Sending Remote Alarm RedTransmit Tx Remote Alarm Indication YellowTransmit Tx AIS BlueTroubleshooting Error Events. Slip Secs Counter Is Increasing. Framing Loss Seconds Counter Is Increasing. Line Code Violations Are Increasing. Verify that isdn switchtype and pri group Are Configured Correctly. Verifying the Signaling Channel. Troubleshooting a PRITroubleshooting Using the show isdn status Command. Using debug q. 92. Performing Hardware Loopback Plug Test. Performing the Loopback Plug Test. Troubleshooting E1 Problems. Troubleshooting Using the show controller e. Command. Show controller e. Conditions. Troubleshooting E1 Error Events. Verifying That isdn switchtype and pri group Are Configured Correctly. Verifying the Signaling Channel. Troubleshooting a PRITroubleshooting Using the show isdn status Command. Using debug q. 92. Troubleshooting Serial Lines. This chapter presents general troubleshooting information and a discussion of tools and techniques for troubleshooting serial connections. The chapter consists of the following sections. Troubleshooting Using the show interfaces serial Command. Using the show controllers Command. Using debug Commands. Using Extended ping Tests. Troubleshooting Clocking Problems. Adjusting Buffers. Special Serial Line Tests. Detailed Information on the show interfaces serial Command. Troubleshooting T1 Problems. Troubleshooting E1 Problems. Troubleshooting Using the show interfaces serial Command. The output of the show interfaces serial exec command displays information specific to serial interfaces. Figure 1. 5 1 shows the output of the show interfaces serial exec command for a High Level Data Link Control HDLC serial interface. This section describes how to use the show interfaces serial command to diagnose serial line connectivity problems in a wide area network WAN environment. The following sections describe some of the important fields of the command output. Other fields shown in the display are described in detail in the section Detailed Information on the show interfaces serial Command, later in this chapter. Serial Lines show interfaces serial Status Line Conditions. You can identify five possible problem states in the interface status line of the show interfaces serial display see Figure 1. Serial x is down, line protocol is down. Serial x is up, line protocol is down. Serial x is up, line protocol is up looped. Serial x is up, line protocol is down disabled. Serial x is administratively down, line protocol is down. Figure 1. 5 1Output of the HDLC show interface serial Command. Table 1. 5 1 shows the interface status conditions, possible problems associated with the conditions, and solutions to those problems. Table 1. 5 1Serial Lines show interfaces serial Status Line Conditions. Status Line Condition. Possible Problem. Serial x is up, line protocol is up. This is the proper status line condition. No action is required. Serial x is down, line protocol is down DTE1 mode. The router is not sensing a CD2 signal that is, the CD is not active. A telephone company problem has occurredline is down or is not connected to CSU3DSU4. Cabling is faulty or incorrect. Hardware failure has occurred CSUDSU. Check the LEDs on the CSUDSU to see whether the CD is active, or insert a breakout box on the line to check for the CD signal. Verify that you are using the proper cable and interface see your hardware installation documentation. Insert a breakout box and check all control leads. Contact your leased line or other carrier service to see whether there is a problem. Swap faulty parts. If you suspect faulty router hardware, change the serial line to another port. If the connection comes up, the previously connected interface has a problem. Serial x is up, line protocol is down DTE mode. A local or remote router is misconfigured. Keepalives are not being sent by the remote router. A leased line or other carrier service problem has occurred noisy line or misconfigured or failed switch. A timing problem has occurred on the cable SCTE5 not set on CSUDSU. A local or remote CSUDSU has failed. Router hardware local or remote has failed. Put the modem, CSU, or DSU in local loopback mode and use the show interfaces serial command to determine whether the line protocol comes up. If the line protocol comes up, a telephone company problem or a failed remote router is the likely problem. If the problem appears to be on the remote end, repeat Step 1 on the remote modem, CSU, or DSU. Verify all cabling. Make certain that the cable is attached to the correct interface, the correct CSUDSU, and the correct telephone company network termination point. The Barefooted Youth there. Use the show controllers exec command to determine which cable is attached to which interface. Enable the debug serial interface exec command. Serial x is up, line protocol is down DTE mode continued Caution Because debugging output is assigned high priority in the CPU process, it can render the system unusable. For this reason, use debug commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco technical support staff. Moreover, it is best to use debug commands during periods of lower network traffic and fewer users. Debugging during these periods decreases the likelihood that increased debug command processing overhead will affect system use. If the line protocol does not come up in local loopback mode, and if the output of the debug serial interface exec command shows that the keepalive counter is not incrementing, a router hardware problem is likely. Swap router interface hardware. If the line protocol comes up and the keepalive counter increments, the problem is not in the local router.