Cisco 3750 poe tar file downloads

Logging messages to a syslog server produces even less, and logging to an internal buffer produces the least overhead of any method. When stack members generate a system error message, the stack master displays the error message to all stack members. The syslog resides on the stack master. Note Make sure to save the syslog to flash memory so that the syslog is not lost if the stack master fails.

The output from the show platform forward privileged EXEC command provides some useful information about the forwarding results if a packet entering an interface is sent through the system. Depending upon the parameters entered about the packet, the output provides lookup table results and port maps used to calculate forwarding destinations, bitmaps, and egress information. Note For more syntax and usage information for the show platform forward command, see the switch command reference for this release.

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 the show platform forward command 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.

It should be forwarded from the port on which the address was learned. Because there is no default route set, the packet should be dropped. It should be forwarded as specified in the routing table. The 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:. The information in the basic file includes the Cisco IOS image name and version that failed, a list of the processor registers, and other switch-specific information. You can provide this information to the Cisco technical support representative by using the show tech-support privileged EXEC command.

Basic crashinfo files are kept in this directory on the flash file system :. 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 the rename privileged EXEC command to rename it, but the contents of the renamed file will not be displayed by the show stacks or the show tech-support privileged EXEC command.

You can delete crashinfo files by using the delete privileged 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 the show stacks or the show tech-support privileged EXEC command. You also can access the file by using any command that can copy or display files, such as the more or the copy privileged EXEC command. The 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 the more or the copy privileged EXEC command. You can configure the switch to not create the extended creashinfo file by using the no exception crashinfo global configuration command.

The switch runs memory consistency check routines to detect and correct invalid ternary content addressable memory TC AM table entries that can affect the performance of the switch. If the switch cannot fix the error, it logs a system error message, specifying the TCAM space in which the error is located:. Beginning in privileged EXEC mode, use the show platform tcam errors command to display the T CAM memory consistency check errors detected on the switch:.

This ex ample shows the output of the show platform tcam errors command:. The number of invalid values found in the TCAM tables.

The number of invalid masks found in the TCAM tables. The number of initial attempts to fix the invalid values or masks.

The number of attempts to fix the invalid values or masks. The number of failed attempts to fix the invalid values or masks. For more information about the show platform tcam errors privileged EXEC command, see the command reference for this release. These tables are a condensed version of troubleshooting documents on Cisco.

This section lists some possible symptoms that could be caused by the CPU being too busy and shows how to verify a CPU utilization problem. Table lists the primary types of CPU utilization problems that you can identify. Note that excessive CPU utilization might result in these symptoms, but the symptoms could also result from other causes.

Note the underlined information in the first line of the output example. This example shows normal CPU utilization. Interrupt 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. This is usually triggered by an event that activated the process. Identify the unusual event, and troubleshoot the root cause. Table lists some PoE troubleshooting scenarios. For more information causes and solutions referenced in the table, see the Troubleshooting Power over Ethernet PoE troubleshooting guide on Cisco.

Trouble is on only one switch port. PoE and non-PoE devices do not work on this port, but do on other ports. Verify that the powered device works on another PoE port. Use the show run, show interface status, or show power inline detail user EXEC commands to verify that the port is not shut down or error disabled. Note Most switches turn off port power when the port is shut down, even though the IEEE specifications make this optional. Verify that the Ethernet cable from the powered device to the switch port is good: Connect a known good non-PoE Ethernet device to the Ethernet cable, and make sure that the powered device establishes a link and exchanges traffic with another host.

Verify that the total cable length from the switch front panel to the powered device is not more than meters. Disconnect the Ethernet cable from the switch port. Use a short Ethernet cable to connect a known good Ethernet device directly to this port on the switch front panel not on a patch panel. Next, connect a powered device to this port, and verify that it powers on. If a powered device does not power on when connected with a patch cord to the switch port, compare the total number of connected powered devices to the switch power budget available PoE.

Use the show inline power and show inline power detail commands to verify the amount of available power. Trouble is on all switch ports. Nonpowered Ethernet devices cannot establish an Ethernet link on any port, and PoE devices do not power on. If there is a continuous, intermittent, or reoccurring alarm related to power, replace the power supply if possible it is a field-replacable unit.

Otherwise, replace the switch. If the problem is on a consecutive group of ports but not all ports, the power supply is probably not defective, and the problem could be related to PoE regulators in the switch.

Use the show log privileged EXEC command to review alarms or system messages that previously reported PoE conditions or status changes. If there are no alarms, use the show interface status command to verify that the ports are not shut down or error-disabled.

If ports are error-disabled, use the shut and no shut interface configuration commands to re-enable the ports. Review the running configuration to verify that power inline never is not configured on the ports. Connect a nonpowered Ethernet device directly to a switch port. Use only a short patch cord. Do not use the existing distribution cables. Enter the shut and no shut interface configuration commands, and verify that an Ethernet link is established.

If this connection is good, use a short patch cord to connect a powered device to this port and verify that it powers on. If the device powers on, verify that all intermediate patch panels are correctly connected. Disconnect all but one of the Ethernet cables from switch ports. Using a short patch cord, connect a powered device to only one PoE port.

Verify the powered device does not require more power than can be delivered by the switch port. Use the show power inline privileged EXEC command to verify that the powered device can receive power when the port is not shut down.

Alternatively, watch the powered device to verify that it powers on. If a powered device can power on when only one powered device is connected to the switch, enter the shut and no shut interface configuration commands on the remaining ports, and then reconnect the Ethernet cables one at a time to the switch PoE ports.

Use the show interface status and show power inline privileged EXEC commands to monitor inline power statistics and port status. If there is still no PoE at any port, a fuse might be open in the PoE section of the power supply. This normally produces an alarm. Check the log again for alarms reported earlier by system messages. After working normally, a Cisco phone or wireless access point intermittently reloads or disconnects from PoE.

Verify all electrical connections from the switch to the powered device. Any unreliable connection results in power interruptions and irregular powered device functioning such as erratic powered device disconnects and reloads.

Verify that the cable length is not more than meters from the switch port to the powered device. Notice what changes in the electrical environment at the switch location or what happens at the powered device when the disconnect occurs? Notice whether any error messages appear at the same time a disconnect occurs. Use the show log privileged EXEC command to review error messages. Verify that an IP phone is not losing access to the Call Manager immediately before the reload occurs.

It might be a network problem and not a PoE problem. Replace the powered device with a non-PoE device, and verify that the device works correctly. If a non-PoE device has link problems or a high error rate, the problem might be an unreliable cable connection between the switch port and the powered device. Non-Cisco powered device does not work on Cisco PoE switch. A non-Cisco powered device is connected to a Cisco PoE switch, but never powers on or powers on and then quickly powers off.

Non-PoE devices work normally. Use the show power inline command to verify that the switch power budget available PoE is not depleted before or after the powered device is connected. Verify that sufficient power is available for the powered device type before you connect it.

Use the show interface status command to verify that the switch detects the connected powered device. Use the show log command to review system messages that reported an overcurrent condition on the port. Identify the symptom precisely: Does the powered device initially power on, but then disconnect? If so, the problem might be an initial surge-in or inrush current that exceeds a current-limit threshold for the port. Table lists some switch stack troubleshooting scenarios.

For more detailed information about causes and solutions referenced in the table, set the Troubleshooting Switch Stacks guide on Cisco. Table Switch Stack Troubleshooting Scenarios. Use the Troubleshooting Switch Stacks document for problem solutions and tutorial information. Incompatible Cisco IOS versions between stack members and new. Enter the show version user EXEC command.

Incompatible license levels in a Catalyst E switch. Enter the show platform stack-manager all command. Incompatible Cisco IOS version numbers between stack members and new switch. When a new member switch with a different SDM template than that of the master switch is added to a stack, it does not reload with the SDM template of the stack master switch and does not display an SDM mismatch condition.

The config. When you enter the ipv6 traffic-filter interface configuration command, it might not filter traffic as expected, and it might allow traffic to pass through. QoS ACL commands might appear differently in the running configuration after the master switch is reloaded or removed from the stack.

The functionality of the commands remains the same. Two stacks that have members with fiber SFP modules are connected in a cross-stack EtherChannel with this configuration:. If a member in one stack is reloaded, this error message appears on a member switch port in the other stack and the port is error disabled. A switch stack reloads when you enter the ip routing global configuration command. The workaround is to use the no ip routing global configuration command to disable IP routing.

When the destination IP address matches the default route, the switch does not forward traffic. The workaround is to use a specific static route such as.

When a spanning-tree bridge protocol data unit BPDU is received on an When a GLC-FEFX SFP module port is in full-duplex mode, it changes to half-duplex mode after you enter the shutdown and the no shutdown interface configuration commands or after the link between the switch and another device fails and then comes up.

The workaround is to enter the no duplex and the duplex full interface configuration commands. If a cookie for the new VLAN on the member is not created when the master sends the member an HRPC message to update the aging timer, the member changes the aging time for VLAN 1 to that set during the topology change. However, the aging time for VLAN 1 does not change.

When you enter the default interface , switchport , or no switchport interface configuration command on the switch, this message appears: EMAC phy access error, port 0, retrying When you use a network scanner to check network devices for security issues, the CPU usage increases.

The workaround is to remove the parser config cache interface command from the configuration. The CPU usage on a standalone switch varies as the switch updates the running configuration. When the switch stack elects a new stack master, by default the MAC address of the new master becomes the stack MAC address. Configuring a persistent MAC address sets a delay after stack master change before the stack master MAC address change. A timer value of 0 means that the MAC address of the current master is used indefinitely.

When you enter the stack-mac persistent timer 0 global configuration command on a stack and the master switch is not the original owner of the stack MAC address, ports on member switches do not go through Rapid Spanning Tree Protocol STP transitions directly into the forwarding state. The workaround is to not use the stack-mac persistent timer 0 command on the switch stack.

This occurs only on some ports and some SKUs. The workaround is to set the speed on the SFP interface to autonegotiate by entering the speed auto interface configuration command. When a Catalyst S FlexStack with four switches is connected to a Catalyst switch, and devices in the same VLAN are connected to the Catalyst S switches but a device in another VLAN is connected to the Catalyst , if you recycle power on one of the Catalyst S switches, connected devices can lose packets.

When quality of service QoS is disabled on a switch, packet fragments might be dropped when more traffic is exiting a port than the bandwidth allows. The port can become oversubscribed because fragments are sent to an incorrect egress queue that has fewer buffers. The workaround is to enable QoS by entering the mls qos global configuration command. When If the startup configuration file is empty on the master switch and Multiple Spanning Tree Protocol MSTP is configured on the switch stack, the stack fails and reloads when you enter the config replace nvram:startup-config user EXEC command.

The workaround is to ensure that a valid startup configuration file exists on the master switch. Catalyst S switches internally support up to 16 different control plane queues. Each queue is dedicated to handling specific protocol packets and is assigned a priority level. For example, STP, routed, and logged packets are sent to three different control plane queues, which are prioritized in corresponding order, with STP having the highest priority. Each queue is allocated a certain amount of processing time based on its priority.

The processing-time ratio between low-level functions and high-level functions is allocated as 1-to Therefore, the control plane logic dynamically adjusts the CPU utilization to handle high-level management functions as well as punted traffic up to the maximum CPU processing capacity.

Basic control plane functions, such as the CLI, are not overwhelmed by functions such logging or forwarding of packets. The Catalyst image is on the Catalyst X and E switches to simplify switch management. To upgrade the stack, use the archive download-sw privileged EXEC command to download images to the active switch. You can display the file list that is in the flash memory:. Explanation The subblock data structure was not initialized. Explanation The switch power supply unit PSU temperature sensor value has reached the warning level.

The external temperature is high. Recommended Action Reduce the temperature in the room. The switch functions normally until the temperature reaches the critical level. Explanation The switch PSU temperature sensor value has reached the critical level, and the switch cannot function normally.

The external temperature is very high. Recommended Action Immediately reduce the room temperature. Explanation The switch PSU temperature sensor value is within normal limits. Explanation The switch temperature sensor value has reached the warning level. Recommended Action Reduce the room temperature. Explanation The authentication process has been stopped.

The first [chars] is the authentication method, [enet] is the Ethernet address of the host, the second [chars] is the interface for the host, and the third [chars] is the session ID. Explanation All available authentication methods have been tried. The first [chars] is the client identifier, the second [chars]s is the interface for the client, and the third [chars] is the session ID. Explanation The client moved to a new interface but did not log off from the first interface. Explanation A new client has triggered a violation that caused an existing client to be replaced.

The first [enet] is the first client, [chars] is the interface, the second [enet] is the new client. The host credentials were not validated. Explanation An entry for the host was created or deleted on the specified interface. Explanation The posture validation status for the host. Explanation The authentication type for the host. Explanation The AAA servers defined by the method list cannot be reached by the host and the applied policy.

The first [chars] is the method list identifer, [inet] is the host identifier, the second [chars] is the policy, and the third [chars] is the session ID. Explanation Authentication was unsuccessful. The first [chars] is the client, the second [chars] is the interface, and the third [chars] is the session ID. Explanation Authentication was successful. This could be a case of IP address theft.

Recommended Action Change the IP address of one of the two systems. The correct information is:. Note By default, the switch automatically selects the interface type the first time a port links up.

For subsequent links, you must use the media-type interface configuration command to manually configure either the RJ connector or the SFP module connector. For more information, see the command reference. Cisco Ethernet Switches are equipped with cooling mechanisms, such as fans and blowers.

However, these fans and blowers can draw dust and other particles, causing contaminant buildup inside the chassis, which can result in a system malfunction. You must install this equipment in an environment as free as possible from dust and foreign conductive material such as metal flakes from construction activities. This applies to all Cisco Ethernet switches except for these compact models:.

When you launch Express Setup, you are prompted for the switch password. Enter the default password, cisco.

The switch ignores text in the username field. Before you complete and exit Express Setup, you must change the password from the default password, cisco. This correction applies to the French, Italian, German, Spanish, Japanese, and simplified Chinese versions of the getting started guide:. These documents provide complete information about the Catalyst , , , S and switches and the Cisco EtherSwitch service modules and are available at Cisco.

These documents provide complete information about the Catalyst switches and the Cisco EtherSwitch service modules:. These documents provide complete information about the Catalyst switches:. These documents provide complete information about the Catalyst and S switches and are available on Cisco.

For other information about related products, see these documents:. SFP compatibility matrix documents are available from this Cisco. Skip to content Skip to search Skip to footer. Available Languages. Download Options. Updated: December 23, Table 2 Catalyst Switches Supported Switch. Support Cisco FlexStack technology. Table 4 Other Supported Hardware Switch.

We recommend 1 GHz. Internet Explorer 6. Cluster Compatibility You cannot create and manage switch clusters through the device manager. When creating a switch cluster or adding a switch to a cluster, follow these guidelines: When you create a switch cluster, we recommend configuring the highest-end switch in your cluster as the command switch.

If you are managing the cluster through Network Assistant, the switch with the latest software should be the command switch.

The standby command switch must be the same type as the command switch. For example, if the command switch is a Catalyst switch, all standby command switches must be Catalyst switches. Deciding Which Files to Use The upgrade procedures in these release notes describe how to perform the upgrade by using a combined tar file. To download software, follow these steps: Step 1 Use Table 6 to identify the file that you want to download.

Step 2 Download the software image file: a. The bootloader can take up to 1 minute to upgrade the first time that the new software is loaded. Do not power cycle the switch during the bootloader upgrade. Switch ping tftp-server-address.

Installation Notes Use these methods to assign IP information to your switch: The Express Setup program , as described in the switch getting started guide.

The CLI-based setup program, as described in the switch hardware installation guide. The DHCP-based autoconfiguration, as described in the switch software configuration guide.

Manually assigning an IP address, as described in the switch software configuration guide. You can use the simulator tool: — for network assessment before deploying applications with stringent network performance requirements. Catalyst and Cisco Mediatrace to troubleshoot and isolate network or application issues in traffic streams. It helps drill down to analyze one-way delay, one-way packet loss, one-way jitter, and connectivity in IPv4 networks that carry video traffic.

You can use Mediatrace for any UDP-based video or non-video traffic stream. Catalyst and Cisco Application Performance Monitor to track the video packet flow and to troubleshoot and isolate performance degradation in traffic streams. You can use the performance monitor for both video and non-video traffic.

Catalyst and EnergyWise Phase 2. Smart logging to capture and export packet flows to a NetFlow collector. Protocol storm protection to control the rate of incoming protocol traffic to a switch by dropping packets that exceed a specified ingress rate VACL Logging to generate syslog messages for ACL denied IP packets Catalyst and Support for Smart Install enhancements including the ability to manually change a client switch health state from denied to allowed or hold for on-demand upgrades, to remove selected clients from the director database, to allow simultaneous on-demand upgrade of multiple clients, and to provide more information about client devices, including device status, health status, and upgrade status.

Memory consistency check routine enhancements to detect and correct invalid ternary content addressable memory TCAM table entries that can affect switch performance Catalyst S. Call Home to provide e-mail-based and web-based notification of critical system events.

Limitations and Restrictions You should review this section before you begin working with the switch. This problem occurs under these conditions: — When the switch is booted up without a configuration no config. CSCec Catalyst or switches and Cisco EtherSwitch service modules When you change a port from a nonrouted port to a routed port or the reverse, the applied auto-QoS setting is not changed or updated when you verify it by using the show running interface or show mls qos interface user EXEC commands.

These are the workarounds: 1. Disable auto-QoS on the interface. The problem is observed only when the switch is receiving frames. The internal Flash memory shipped with the switches are either 16 MB or 32 MB based on the model of the Catalyst switch.

Refer to the Cisco Catalyst Data Sheet for more information. There is a limit to the number of images that you can store in Flash. Always check the size, in bytes, of the image in the Downloads - Switches registered customers only before you upgrade software. Issue the dir flash: command in order to compare the size of this image with the free space in Flash. Here is a sample command output to delete a Cisco IOS image with a web-based device manager directory :.

An upgrade can require you to free up even more space. The requirement depends on how many images you have stored in Flash. In this section, you are presented with the information to configure the features described in this document.

The procedure in this section copies the combined tar file to the switch. You copy the file to the switch from a TFTP server and extract the files. You can download an image file and replace the current image, or you can keep the current image. Note: For switch stacks, the archive download-sw and archive upload-sw privileged EXEC commands can only be used through the stack master.

Software images downloaded to the stack master are automatically downloaded to the rest of the stack members. Thus, you must be logged on to the master switch to perform this upgrade. Use the Decide Which Files to Use section of this document in order to identify the type of image and feature set that you want to download. Refer to Software Download - Cisco Catalyst Software registered customers only and find the image that you want to download.

In order to obtain authorization and to download the cryptographic software files, click Catalyst Strong Cryptographic 3DES Software. The bootloader can take up to 1 minute to upgrade the first time that you load the new software. Do not power cycle the switch during the bootloader upgrade. Issue the dir flash: command on the in order to verify the amount of free memory that you have for the upgrade.

There are several options for the download of the image. You can use the command-line options that appear in this section to have a new image overwrite the old image or leave the old image in flash. The example uses the archive download-sw command in order to retain the old image on the device. For a complete description of the commands available, refer to the archive download-sw section of Catalyst Switch Cisco IOS Commands.

The image copy is complete, and you are ready for the reboot. In order to verify that the current state of the switches is Ready , issue the show switch detail command. In order to verify that the new image is in flash for the stack members, issue the dir flash: command and the dir flash 1: command. In this example, there are two switch stack members. If the stack configuration includes additional switches in the stack, issue the dir flash : command for each additional switch in the stack.

Issue the show version command in order to verify that the old image is still the current operation system image. Issue the show boot command in order to verify that the new image is now the image in the BOOT path-list that will load at the next switch reload. Issue the reload command at the prompt and confirm in order to proceed with the reload.

The new code revision should come up and start to run as expected on all the switches in the stack. To maximize switch performance and ensure a link, follow one of these guidelines when changing the settings for duplex and speed:. Note If a remote device does not autonegotiate, configure the duplex settings on the two ports to match. The speed parameter can adjust itself even if the connected port does not autonegotiate. If a powered device such as a Cisco IP Phone 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 the shutdown interface configuration command, and then enter the no shutdown interface command. You can also configure automatic recovery on the switch to recover from the error-disabled state.

On a Catalyst X switch, the errdisable recovery cause loopback and the errdisable recovery interval seconds global 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:. If a Cisco powered device is connected to a port and you configure the port by using the power inline never interface configuration command, a false link up can occur, placing the port into an error-disabled state. To take the port out of the error-disabled state, enter the shutdown and the no shutdown i nterface configuration commands.

You should not connect a Cisco powered device to a port that has been configured with the power inline never command. 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. Although the error message text refers to GBIC interfaces and modules, the security messages actually refer to the SFP modules and module interfaces.

For more information about error messages, see the system message guide for this release. After inserting a Cisco SFP module, use the errdisable recovery cause gbic-invalid global 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 the errdisable recovery command, 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. 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 the show interfaces transceiver command in the command reference for this release.

The switch monitors the temperature conditions and uses the temperature information to control the fans. Use the show env temperature status 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 the system env temperature threshold yellow value global 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. The 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:. If you attempt to ping a host in a different IP subnetwork, you must define a static route to the network or have IP routing configured to route between those subnets.

IP routing is disabled by default on all switches. Beginning in privileged EXEC mode, use this command to ping another device on the network from the switch:.

Ping a remote host through IP or by supplying the hostname or network address. Note Though other protocol keywords are available with the ping command, they are not supported in this release. Table describes the possible ping character output. Table Ping Output Display Characters. Each period means the network server timed out while waiting for a reply. Simultaneously press and release the Ctrl , Shift , and 6 keys and then press the X key.

The 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. If any devices in the physical path are transparent to CDP, the switch cannot identify the path through these devices.

If the IP address is not resolved, the path is not identified, and an error message appears. You can display physical path that a packet takes from a source device to a destination device by using one of these privileged EXEC commands:.

You 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 the traceroute privileged EXEC command and might or might not appear as a hop in the traceroute command 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.

Traceroute finds the address of the first hop by examining the source address field of the ICMP time-to-live-exceeded message. 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 ICMP port-unreachable error 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.

Beginning in privileged EXEC mode, follow this step to trace that the path packets take through the network:. Trace the path that packets take through the network. Note Though other protocol keywords are available with the traceroute privileged EXEC command, they are not supported in this release.

This example shows how to perform a traceroute to an IP host:. The display shows the hop count, the IP address of the router, and the round-trip time in milliseconds for each of the three probes that are sent.

Table Traceroute Output Display Characters. Administratively unreachable. Usually, this output means that an access list is blocking traffic. When running TDR, a local device sends a signal through a cable and compares the reflected signal to the initial signal. If one of the twisted-pair wires is open, TDR can find the length at which the wire is open. Use TDR to diagnose and resolve cabling problems in these situations:. When you run TDR, the switch reports accurate information if.

When you run TDR, the switch does not report accurate information if. When you run TDR on an interface, you can run it on the stack master or a stack member. To display the results, enter the show cable-diagnostics tdr interface interface-id privileged EXEC command. For a description of the fields in the display, see the command reference for this release. Note For complete syntax and usage information for specific debug commands, see the command reference for this release.

In a Catalyst 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 the session switch-number privileged EXEC command. Then, enter the debug command at the command-line prompt of the stack member. All debug commands are entered in privileged EXEC mode, and most debug commands take no arguments. The switch continues to generate output until you enter the no form of the command.

If you enable a debug command and no output appears, consider these possibilities:. Alternately, in privileged EXEC mode, you can enter the undebug form of the command:. To display the state of each debugging option, enter this command in privileged EXEC mode:.

Beginning in privileged EXEC mode, enter this command to enable all-system diagnostics:. The no debug all privileged EXEC command disables all diagnostic output. Using the no debug all command is a convenient way to ensure that you have not accidentally left any debug commands enabled. By default, the network server sends the output from debug commands 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.

Note Be aware that the debugging destination you use affects system overhead. Logging messages to the console produces very high overhead, whereas logging messages to a virtual terminal produces less overhead. Logging messages to a syslog server produces even less, and logging to an internal buffer produces the least overhead of any method. When stack members generate a system error message, the stack master displays the error message to all stack members. The syslog resides on the stack master.

Note Make sure to save the syslog to flash memory so that the syslog is not lost if the stack master fails. The output from the show platform forward privileged EXEC command provides some useful information about the forwarding results if a packet entering an interface is sent through the system.

Depending upon the parameters entered about the packet, the output provides lookup table results and port maps used to calculate forwarding destinations, bitmaps, and egress information. Note For more syntax and usage information for the show platform forward command, see the switch command reference for this release. 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 the show platform forward command 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. It should be forwarded from the port on which the address was learned. Because there is no default route set, the packet should be dropped.

It should be forwarded as specified in the routing table. The 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:. The 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 the show tech-support privileged EXEC command. Basic crashinfo files are kept in this directory on the flash file system :. 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 the rename privileged EXEC command to rename it, but the contents of the renamed file will not be displayed by the show stacks or the show tech-support privileged EXEC command.