Row8Cage1AS#show snmp mib in Temperature. Rack1SW1#sho ver in Software Cisco IOS Software, IOS-XE Software, Catalyst L3 Switch Software. Jul 31, 2008 - fan Show fan status power Show power supply status rps Show RPS status temperature Show temperature status switch# show environment all.
This chapter describes how to identify and resolve software problems related to the Cisco IOS software on the Catalyst 3750-X or 3560-X switch. Depending on the nature of the problem, you can use the command-line interface (CLI), the device manager, or Network Assistant to identify and solve problems.Unless otherwise noted, the termswitchrefers to a Catalyst 3750-X or 3560-X standalone switch and to a Catalyst 3750-X switch stack.Additional troubleshooting information, such as LED descriptions, is provided in the hardware installation guide. Recovering from a Software FailureSwitch software can be corrupted during an upgrade, by downloading the wrong file to the switch, and by deleting the image file. In all of these cases, the switch does not pass the power-on self-test (POST), and there is no connectivity.This procedure uses boot loader commands and TFTP to recover from a corrupted or wrong image file.This recovery procedure requires that you have physical access to the switch.Step 1From your PC, download the software image tar file (imagefilename.tar) from Cisco.com.The Cisco IOS image is stored as abinfile in a directory in the tar file. For information about locating the software image files on Cisco.com, see the release notes.Step 2Extract the bin file from the tar file.If you are using Windows, use a zip program that can read a tar file. Use the zip program to navigate to and extract the bin file.If you are using UNIX, follow these steps:1.Display the contents of the tar file by using thetar -tvf UNIX command.
These sections describes how to recover a forgotten or lost switch password:.You enable or disable password recovery by using theservicepassword-recoveryglobal configuration command. When you enter theservice password-recoveryorno service password-recoverycommandon the stack master, it is propagated throughout the stack and applied to all switches in the stack.Follow the steps in this procedure if you have forgotten or lost the switch password.Step 1Use one of these methods to connect a terminal or PC to the switch:.Connect a terminal or a PC with terminal-emulation software to the switch console port. If you are recovering the password for a switch stack, connect to the console port of the stack master.Connect a PC to the Ethernet management port. If you are recovering the password for a switch stack, connect to the Ethernet management port of a Catalyst 3750-X stack member. For details about using the internal Ethernet management port, see the and the hardware installation guide.Step 2Set the line speed on the emulation software to 9600 baud.Step 3On a Catalyst 3750-X switch, power off the standalone switch or the entire switch stack. On a Catalyst 3560-X switch, power off the switch.Step 4Reconnect the power cord to the switch or the stack master.
Within 15 seconds, press theModebutton while the System LED is still flashing green. Continue pressing theModebutton until the System LED turns briefly amber and then solid green; then release theModebutton.Several lines of information about the software appear with instructions, informing you if the password recovery procedure has been disabled or not.If you see a message that begins with this. Note.Make sure that the switches that you add to or remove from the switch stack are powered off. For all powering considerations in switch stacks, see the “Switch Installation” chapter in the hardware installation guide.After adding or removing stack members, make sure that the switch stack is operating at full bandwidth (32 Gb/s). Press the Mode button on a stack member until the Stack mode LED is on. The last two port LEDs on the switch should be green. Depending on the switch model, the last two ports are either 10/100/1000 ports or small form-factor pluggable (SFP) module.
If one or both of the last two port LEDs are not green, the stack is not operating at full bandwidth.We recommend using only one CLI session when managing the switch stack. Be careful when using multiple CLI sessions to the stack master. Commands that you enter in one session are not displayed in the other sessions. Therefore, it is possible that you might not be able to identify the session from which you entered a command.Manually assigning stack member numbers according to the placement of the switches in the stack can make it easier to remotely troubleshoot the switch stack. However, you need to remember that the switches have manually assigned numbers if you add, remove, or rearrange switches later. Use theswitchcurrent-stack-member-numberrenumbernew-stack-member-numberglobal configuration command to manually assign a stack member number. For more information about stack member numbers, see the.
If you replace a stack member with an identical model, the new switch functions with the exact same configuration as the replaced switch. This is also assuming the new switch is using the same member number as the replaced switch.Removing powered-on stack members causes the switch stack to divide (partition) into two or more switch stacks, each with the same configuration. If you want the switch stacks to remain separate, change the IP address or addresses of the newly created switch stacks. To recover from a partitioned switch stack:1.Power off the newly created switch stacks.2.Reconnect them to the original switch stack through their StackWise Plus ports.3.Power on the switches.For the commands that you can use to monitor the switch stack and its members, see the. If you have not configured a standby command switch, and your command switch loses power or fails in some other way, management contact with the member switches is lost, and you must install a new command switch.
However, connectivity between switches that are still connected is not affected, and the member switches forward packets as usual. You can manage the members as standalone switches through the console port, through the Ethernet management port, or, if they have IP addresses, through the other management interfaces.You can prepare for a command switch failure by assigning an IP address to a member switch or another switch that is command-capable, making a note of the command-switch password, and cabling your cluster to provide redundant connectivity between the member switches and the replacement command switch. These sections describe two solutions for replacing a failed command switch:.These recovery procedures require that you have physical access to the switch.For information on command-capable switches, see the release notes. Replacing a Failed Command Switch with a Cluster MemberTo replace a failed command switch with a command-capable member in the same cluster, follow these steps:Step 1Disconnect the command switch from the member switches, and physically remove it from the cluster.Step 2Insert the member switch in place of the failed command switch, and duplicate its connections to the cluster members.Step 3Start a CLI session on the new command switch.You can access the CLI by using the console port, by using the Ethernet management port, or, if an IP address has been assigned to the switch, by using Telnet. For details about using the console port, see the switch hardware installation guide. For details about using the Ethernet management port, see the and the hardware installation guide.Step 4At the switch prompt, enter privileged EXEC mode. If this prompt does not appear, enterenable, and pressReturn.
Enter setup, and pressReturnto start the setup program.Step 11Respond to the questions in the setup program.When prompted for the hostname, recall that on a command switch, the hostname is limited to 28 characters; on a member switch to 31 characters. Replacing a Failed Command Switch with Another SwitchTo replace a failed command switch with a switch that is command-capable but is not part of the cluster, follow these steps:Step 1Insert the new switch in place of the failed command switch, and duplicate its connections to the cluster members.Step 2Start a CLI session on the new command switch.You can access the CLI by using the console port, by using the Ethernet management port, or, if an IP address has been assigned to the switch, by using Telnet. For details about using the console port, see the switch hardware installation guide. For details about using the Ethernet management port, see the and the hardware configuration guide.Step 3At the switch prompt, enter privileged EXEC mode. If this prompt does not appear, enterenable, and pressReturn. Enter setup, and pressReturnto start the setup program.Step 7Respond to the questions in the setup program.When prompted for the hostname, recall that on a command switch, the hostname is limited to 28 characters. Recovering from Lost Cluster Member ConnectivitySome configurations can prevent the command switch from maintaining contact with member switches.
Preventing Autonegotiation MismatchesThe IEEE 802.3ab autonegotiation protocol manages the switch settings for speed (10 Mb/s, 100 Mb/s, and 1000 Mb/s, excluding SFP module ports) and duplex (half or full). There are situations when this protocol can incorrectly align these settings, reducing performance. A mismatch occurs under these circumstances:.A manually set speed or duplex parameter is different from the manually set speed or duplex parameter on the connected port.A port is set to autonegotiate, and the connected port is set to full duplex with no autonegotiation.To maximize switch performance and ensure a link, follow one of these guidelines when changing the settings for duplex and speed:.Let both ports autonegotiate both speed and duplex.Manually set the speed and duplex parameters for the ports on both ends of the connection. Disabled Port Caused by Power LossIf a powered device (such as a Cisco IP Phone 7910) that is connected to a PoE switch port and is powered by an AC power source loses power from the AC power source, the device might enter an error-disabled state. To recover from an error-disabled state, enter theshutdowninterface configuration command, and then enter theno shutdowninterface command. You can also configure automatic recovery on the switch to recover from the error-disabled state.On a Catalyst 3750-X switch, theerrdisable recovery cause loopbackand theerrdisable recovery intervalsecondsglobal configuration commands automatically take the interface out of the error-disabled state after the specified period of time.Use these commands, described in the command reference for this release, to monitor the PoE port status:.show controllers power inlineprivileged EXEC command.show power inlineprivileged EXEC command.debug ilpowerprivileged EXEC command.
SFP Module Security and IdentificationCisco small form-factor pluggable (SFP) modules have a serial EEPROM that contains the module serial number, the vendor name and ID, a unique security code, and cyclic redundancy check (CRC). When an SFP module is inserted in the switch, the switch software reads the EEPROM to verify the serial number, vendor name and vendor ID, and recompute the security code and CRC.
If the serial number, the vendor name or vendor ID, the security code, or CRC is invalid, the software generates a security error message and places the interface in an error-disabled state. If you are using a non-Cisco SFP module, remove the SFP module from the switch, and replace it with a Cisco module. After inserting a Cisco SFP module, use theerrdisable recovery cause gbic-invalidglobal configuration command to verify the port status, and enter a time interval for recovering from the error-disabled state. After the elapsed interval, the switch brings the interface out of the error-disabled state and retries the operation. For more information about theerrdisable recoverycommand, see the command reference for this release.If the module is identified as a Cisco SFP module, but the system is unable to read vendor-data information to verify its accuracy, an SFP module error message is generated. In this case, you should remove and re-insert the SFP module.
If it continues to fail, the SFP module might be defective. Monitoring SFP Module StatusYou can check the physical or operational status of an SFP module by using theshow interfaces transceiverprivileged EXEC command. This command shows the operational status, such as the temperature and the current for an SFP module on a specific interface and the alarm status. You can also use the command to check the speed and the duplex settings on an SFP module.
For more information, see theshow interfaces transceivercommand in the command reference for this release. Monitoring TemperatureThe switch monitors the temperature conditions and uses the temperature information to control the fans.Use theshow env temperaturestatus privileged EXEC command to display the temperature value, state, and thresholds. The temperature value is the temperature in the switch (not the external temperature).You can configure only the yellow threshold level (in Celsius) by using thesystem env temperature threshold yellowvalueglobal configuration command to set the difference between the yellow and red thresholds. You cannot configure the green or red thresholds.
For more information, see the command reference for this release. Understanding PingThe switch supports IP ping, which you can use to test connectivity to remote hosts. Ping sends an echo request packet to an address and waits for a reply. Ping returns one of these responses:.Normal response—The normal response (hostnameis alive) occurs in 1 to 10 seconds, depending on network traffic.Destination does not respond—If the host does not respond, ano-answermessage is returned.Unknown host—If the host does not exist, anunknown hostmessage is returned.Destination unreachable—If the default gateway cannot reach the specified network, adestination-unreachablemessage is returned.Network or host unreachable—If there is no entry in the route table for the host or network, anetwork or host unreachablemessage is returned. Understanding Layer 2 TracerouteThe Layer 2 traceroute feature allows the switch to identify the physical path that a packet takes from a source device to a destination device. Layer 2 traceroute supports only unicast source and destination MAC addresses.
It finds the path by using the MAC address tables of the switches in the path. When the switch detects a device in the path that does not support Layer 2 traceroute, the switch continues to send Layer 2 trace queries and lets them time out.The switch can only identify the path from the source device to the destination device. It cannot identify the path that a packet takes from source host to the source device or from the destination device to the destination host.
Usage Guidelines.Cisco Discovery Protocol (CDP) must be enabled on all the devices in the network. For Layer 2 traceroute to function properly, do not disable CDP.If any devices in the physical path are transparent to CDP, the switch cannot identify the path through these devices. For more information about enabling CDP, see.A switch is reachable from another switch when you can test connectivity by using thepingprivileged EXEC command. All switches in the physical path must be reachable from each other.The maximum number of hops identified in the path is ten.You can enter thetraceroute macor thetraceroute mac ipprivileged EXEC command on a switch that is not in the physical path from the source device to the destination device.
All switches in the path must be reachable from this switch.Thetraceroute maccommand output shows the Layer 2 path only when the specified source and destination MAC addresses belong to the same VLAN. If you specify source and destination MAC addresses that belong to different VLANs, the Layer 2 path is not identified, and an error message appears.If you specify a multicast source or destination MAC address, the path is not identified, and an error message appears.If the source or destination MAC address belongs to multiple VLANs, you must specify the VLAN to which both the source and destination MAC addresses belong. If the VLAN is not specified, the path is not identified, and an error message appears.Thetraceroute mac ipcommand output shows the Layer 2 path when the specified source and destination IP addresses belong to the same subnet.
When you specify the IP addresses, the switch uses the Address Resolution Protocol (ARP) to associate the IP addresses with the corresponding MAC addresses and the VLAN IDs.–If an ARP entry exists for the specified IP address, the switch uses the associated MAC address and identifies the physical path.–If an ARP entry does not exist, the switch sends an ARP query and tries to resolve the IP address. If the IP address is not resolved, the path is not identified, and an error message appears.When multiple devices are attached to one port through hubs (for example, multiple CDP neighbors are detected on a port), the Layer 2 traceroute feature is not supported. When more than one CDP neighbor is detected on a port, the Layer 2 path is not identified, and an error message appears.This feature is not supported in Token Ring VLANs. Understanding IP TracerouteYou can use IP traceroute to identify the path that packets take through the network on a hop-by-hop basis. The command output displays all network layer (Layer 3) devices, such as routers, that the traffic passes through on the way to the destination.Your switches can participate as the source or destination of thetracerouteprivileged EXEC command and might or might not appear as a hop in thetraceroutecommand output. If the switch is the destination of the traceroute, it is displayed as the final destination in the traceroute output.
Intermediate switches do not show up in the traceroute output if they are only bridging the packet from one port to another within the same VLAN. However, if the intermediate switch is a multilayer switch that is routing a particular packet, this switch shows up as a hop in the traceroute output.Thetracerouteprivileged EXEC command uses the Time To Live (TTL) field in the IP header to cause routers and servers to generate specific return messages. Traceroute starts by sending a User Datagram Protocol (UDP) datagram to the destination host with the TTL field set to 1. If a router finds a TTL value of 1 or 0, it drops the datagram and sends an Internet Control Message Protocol (ICMP) time-to-live-exceeded message to the sender. Traceroute finds the address of the first hop by examining the source address field of the ICMP time-to-live-exceeded message.To identify the next hop, traceroute sends a UDP packet with a TTL value of 2. The first router decrements the TTL field by 1 and sends the datagram to the next router.
The second router sees a TTL value of 1, discards the datagram, and returns the time-to-live-exceeded message to the source. This process continues until the TTL is incremented to a value large enough for the datagram to reach the destination host (or until the maximum TTL is reached).To learn when a datagram reaches its destination, traceroute sets the UDP destination port number in the datagram to a very large value that the destination host is unlikely to be using. When a host receives a datagram destined to itself containing a destination port number that is unused locally, it sends an ICMPport-unreachableerror to the source. Because all errors except port-unreachable errors come from intermediate hops, the receipt of a port-unreachable error means that this message was sent by the destination port. Understanding TDRYou can use the Time Domain Reflector (TDR) feature to diagnose and resolve cabling problems. When running TDR, a local device sends a signal through a cable and compares the reflected signal to the initial signal.TDR is supported only on 10/100/1000 copper Ethernet ports.
It is not supported on 10-Gigabit Ethernet ports and on SFP module ports.TDR can detect these cabling problems:.Open, broken, or cut twisted-pair wires—The wires are not connected to the wires from the remote device.Shorted twisted-pair wires—The wires are touching each other or the wires from the remote device. Enabling Debugging on a Specific FeatureIn a Catalyst 3750-X switch stack, when you enable debugging, it is enabled only on the stack master. To enable debugging on a stack member, you must start a session from the stack master by using thesessionswitch-numberprivileged EXEC command.
Then, enter thedebugcommand at the command-line prompt of the stack member.Alldebugcommands are entered in privileged EXEC mode, and mostdebugcommands take no arguments. For example, beginning in privileged EXEC mode, enter this command to enable the debugging for Switched Port Analyzer (SPAN).
The switch continues to generate output until you enter thenoform of the command.If you enable adebugcommand and no output appears, consider these possibilities:.The switch might not be properly configured to generate the type of traffic you want to monitor. Use theshow running-configcommand to check its configuration.Even if the switch is properly configured, it might not generate the type of traffic you want to monitor during the particular period that debugging is enabled.
Depending on the feature you are debugging, you can use commands such as the TCP/IPpingcommand to generate network traffic.To disable debugging of SPAN, enter this command in privileged EXEC mode. Redirecting Debug and Error Message OutputBy default, the network server sends the output fromdebugcommands and system error messages to the console. If you use this default, you can use a virtual terminal connection to monitor debug output instead of connecting to the console port or the Ethernet management port.Possible destinations include the console, virtual terminals, internal buffer, and UNIX hosts running a syslog server.
The syslog format is compatible with 4.3 Berkeley Standard Distribution (BSD) UNIX and its derivatives. Most of the information in the output from the command is useful mainly for technical support personnel, who have access to detailed information about the switch application-specific integrated circuits (ASICs). However, packet forwarding information can also be helpful in troubleshooting.This is an example of the output from theshow platform forwardcommand on port 1 in VLAN 5 when the packet entering that port is addressed to unknown MAC addresses. The packet should be flooded to all other ports in VLAN 5.
Using the crashinfo FilesThe crashinfo files save information that helps Cisco technical support representatives to debug problems that caused the Cisco IOS image to fail (crash). The switch writes the crash information to the console at the time of the failure. The switch creates two types of crashinfo files:.Basic crashinfo file—The switch automatically creates this file the next time you boot up the Cisco IOS image after the failure.Extended crashinfo file—The switch automatically creates this file when the system is failing. Basic crashinfo FilesThe information in the basic file includes the Cisco IOS image name and version that failed, a list of the processor registers, and a stack trace.
You can provide this information to the Cisco technical support representative by using theshow tech-supportprivileged EXEC command.Basic crashinfo files are kept in this directory on the flash file system:flash:/crashinfo/.The filenames are crashinfonwherenis a sequence number.Each new crashinfo file that is created uses a sequence number that is larger than any previously existing sequence number, so the file with the largest sequence number describes the most recent failure. Version numbers are used instead of a timestamp because the switches do not include a real-time clock. You cannot change the name of the file that the system will use when it creates the file. However, after the file is created, you can use therenameprivileged EXEC command to rename it, but the contents of the renamed file will not be displayed by theshow stacksor theshow tech-supportprivileged EXEC command. You can delete crashinfo files by using thedeleteprivileged EXEC command.You can display the most recent basic crashinfo file (that is, the file with the highest sequence number at the end of its filename) by entering theshow stacksor theshow tech-supportprivileged EXEC command. You also can access the file by using any command that can copy or display files, such as themoreor thecopyprivileged EXEC command. Extended crashinfo FilesThe switch creates the extended crashinfo file when the system is failing.
The information in the extended file includes additional information that can help determine the cause of the switch failure. You provide this information to the Cisco technical support representative by manually accessing the file and using themoreor thecopyprivileged EXEC command.Extended crashinfo files are kept in this directory on the flash file system:flash:/crashinfoext/.The filenames are crashinfoextnwherenis a sequence number.You can configure the switch to not create the extended creashinfo file by using theno exception crashinfoglobal configuration command.
Understanding OBFLBy default, OBFL is enabled. It collects information about the switch and small form-factor pluggable (SFP) modules. Configuring OBFLTo enable OBFL, use thehw-module moduleswitch-numberlogging onboardmessage levellevelglobal configuration command. On Catalyst 3750-X switches, the range forswitch-numberis from 1 to 9. On Catalyst 3750-X switches, the switch number is always 1. Use themessage levellevelparameter to specify the severity of the hardware-related messages that the switch generates and stores in the flash memory.To copy the OBFL data to the local network or a specific file system, use thecopy logging onboard modulestack-member destinationprivileged EXEC command.
Possible Symptoms of High CPU UtilizationNote that excessive CPU utilization might result in these symptoms, but the symptoms could also result from other causes.Spanning tree topology changes.EtherChannel links brought down due to loss of communication.Failure to respond to management requests (ICMP ping, SNMP timeouts, slow Telnet or SSH sessions).UDLD flapping.IP SLAs failures because of SLAs responses beyond an acceptable threshold.DHCP or IEEE 802.1x failures if the switch does not forward or respond to requestsLayer 3 switches. Corrective ActionInterrupt percentage value is almost as high as total CPU utilization value.The CPU is receiving too many packets from the network.Determine the source of the network packet.
Stop the flow, or change the switch configuration. See the section onTotal CPU utilization is greater than 50% with minimal time spent on interrupts.One or more Cisco IOS process is consuming too much CPU time.
This is usually triggered by an event that activated the process.Identify the unusual event, and troubleshoot the root cause. See the section onFor complete information about CPU utilization and how to troubleshoot utilization problems, see thedocumenton Cisco.com. Possible cause and solutionNo PoE on only one port.Trouble is on only one switch port.
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