01:03 AM The clear counters command is used to reset interface statistics. You can use IP ping to test connectivity to remote hosts. The Carri-Sen (carrier sense) counter increments every time an Ethernet controller wants to send data on a half-duplex connection. Customers Also Viewed These Support Documents. Also you can use (it is disruptive for the port): test cable-diagnostics tdr interface xx/yy and then Switchport status changes.. when a connected device goes sleep (e.g printer) or users shutdown their PC/laptops. INZA.@iQ/eY}`9@deB;r2.5I>/k^'`P(YTqSIuhBj6c/
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/iJ}#!s;Z7)z5A2AY+}qEVV"'W$Rd9}rol0)^}q{Fm>%,$N4A9$:[!\v;< @QOi"q8ITnV2abvyY;z2js^wB>_T m*wHQOWB-G`\ O;}ww ?PxWEs?\xKa[,bvZ,h"0.uB[bT\uOU|eL;HLQXdh8j>A . SSH is supported for remote logins to the switch only. This command displays output similar to a Cisco router, like software image name and version information and system memory sizes. This counter is updated only when packets are process switched, not when packets are fast switched. See "Working with System Software Images," for the software image naming conventions that are used for the encryption images. /Border [0 0 0] /Type /Pages Description:show interfacescounter indicates that the transmit jabber timer expired. Baby Giant frames are just slightly larger than the maximum size of an ethernet frame. This is an indication of a bad frame generated by the connected device. If steps 3 and 4 are successful, but a connection between device A and B cannot be established, loop ports with the cable that adjoins the two devices. /Title (Checking Port Status and Connectivity) Undersize = frame < 64bytes. output buffer failures output buffers swapped out. In addition, you can use Telnet from the switch to access other devices in the network. View with Adobe Reader on a variety of devices, View in various apps on iPhone, iPad, Android, Sony Reader, or Windows Phone, View on Kindle device or Kindle app on multiple devices, Check the Cable and Both Sides of the Connection, Ethernet and Fast Ethernet Maximum Transmission Distances, Troubleshoot the Most Common Port and Interface Commands for Cisco IOS, Understand the Specific Port and Interface Counter Output for Cisco IOS, Show Controller Ethernet-Controller for Cisco IOS, %INTR_MGR-DFC1-3-INTR: Queueing Engine (Blackwater) [1]: FIC Fabric-A Received Unexpected Control Code, Command Rejected: [Interface] not a Switching Port, Port or Interface Status is Disable or Shutdown, Uplink Port or Interface Status is Inactive, Deferred Counter on the Catalyst Switch Interface Increments, Intermittent Failure to set timer [value] from vlan [vlan no], Use of Switchport Host to Fix Startup Delays, Speed/Duplex, auto-negotiation, or NIC Issues, Deferred Frames (Out-Lost or Out-Discard), Input Errors on a Layer 3 Interface Connected to a Layer 2 Switchport, Rapidly Increment Rx-No-Pkt-Buff Counter and Input Errors, Connectivity Issues due to Oversubscription, Last Input Never from the Output of Show interface Command, Mode-Conditioning Patch Cord Installation Note, Configuring and Troubleshooting Ethernet 10/100/1000 MB Half/Full Duplex Auto-Negotiation, Most Common Port and Interface Troubleshooting Commands for Cisco IOS, Recover Errdisable Port State on Cisco IOS Platforms, Understanding and Configuring VLAN Trunk Protocol (VTP), Configuring Jumbo/Giant Frame Support on Catalyst Switches, Using Portfast and Other Commands to Fix Workstation Startup Connectivity Delays, Troubleshooting Cisco Catalyst Switches to NIC Compatibility Issues, Spanning-Tree Protocol Enhancements using Loop Guard and BPDU Skew Detection Features, Understand and Configure the Unidirectional Link Detection Protocol (UDLD) Feature, Using PortFast and Other Commands to Fix Workstation Startup Connectivity Delays, Configuring and Troubleshooting Ethernet 10/100/1000Mb Half/Full Duplex Auto-Negotiation, Upgrade Software Images and Working with Configuration Files on Catalyst Switches, Technical Support & Documentation - Cisco Systems. This only happens under stress conditions but can happen with bursts of traffic on several ports. For example, if a static map for MAC address X was configured on port 0/2 to forward traffic to port 0/3, the packet must be received on port 0/2 otherwise the packet is dropped. I don't think this command actually woks. ". The issue occurs when an excessive amount of traffic is processed by the Fast Ethernet interface. Aging Type : Absolute. To open a Telnet session to another device on the network from the switch, perform this task in privileged mode: This example shows how to open a Telnet session from the switch to the remote host labsparc: The login timer is the number of minutes after which an idle session is disconnected. >> As the half-duplex side transmits, the full duplex side does not wait its turn and transmits simultaneously which causes a late collision. For general configuration information and additional information on how to troubleshoot, refer to Configuring and Troubleshooting Ethernet 10/100/1000 MB Half/Full Duplex Auto-Negotiation . /ModDate (D:20110317115332Z) Newer Cisco IOS contain a count parameter that can count lines which match a regex. FCS error count is the number of frames that were received with a bad checksum (CRC value) in the Ethernet frame. Swap suspect cable with known good cable. If the ratio of errors to input packets is greater than two or three percent, performance degradation can be noticed. << Check the Command Reference for your release of software to verify the availability of this command. You can change the topology to route frames differently. To change the logout timer value, perform this task in privileged mode: Change the logout timer value (a timeout value of 0 prevents idle sessions from being disconnected automatically). Note:The Catalyst 6500/6000 series switches do not clear the bit counters of an interface with theclear counterscommand. /Type /Annot Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Note: Use this Recover Errdisable Port State on Cisco IOS Platformsfor more information on errdisable status on switches that run Cisco IOS. Check the results of the POST results from the switch to see if there were any failures indicated for any part of the switch. If this link is run in 1G (1000BASE-TX) mode, Gigabit sync, which occurs every 10msec, must be able to detect the link down faster. All of the devices used in this document started with a cleared (default) configuration. For information in regard to the recovery from corrupted images, choose your platform Switch and look at the Troubleshootsection. If a packet cannot be completely received because the switch is out of packet buffers, this counter is incremented once for every dropped packet. endobj Look at the "sh interface " and "sh controll e " any any line errors. The next two sections describe how to use IP traceroute. Common Causes: This error can indicate a duplex mismatch among other things. This example shows how to disconnect an active console port session and an active Telnet session: The next two sections describe how to use IP ping. Without attenuators, the minimum link distance is 24.9 miles (40 km). Jumbo frames are not defined as part of the IEEE Ethernet standard and are vendor-dependent. Giant frames are defined as any frame over the maximum size of an ethernet frame (larger than 1518 bytes) that has a bad FCS. If either device has multiple Gigabit ports, connect the ports to each other. /R [41 63 585 621] Alignment errors are the result of collisions at half-duplex, a duplex mismatch, bad hardware (NIC, cable, or port), or connected devices that generate frames that do not end with an octet and have a bad FCS. NFS file transfers that come from a Gigabit attached server that uses user datagram protocol (UDP) with a 32K window size is one example of an application setup that can bring out this type of problem. The size of this buffer is only 16 KB. Port Overview The Switch Ports section shows a basic view of the status of all switch ports. Input queue - The number of packets in the input queue.Size/max/drops= the current number of frames in the queue / the max number of frames the queue can hold before it must start to drop frames / the actual number of frames dropped because the max queue size was exceeded.Flushesis used to count Selective Packet Discard (SPD) drops on the Catalyst 6000 Series that run Cisco IOS. A unidirectional link is a link where traffic goes out one way, but no traffic is received in the ingress direction. Alignment errors are the number of frames received that do not end with an even number of octets and have a bad CRC. This can be a sign that this segment is run at an inferior speed and/or duplex, or there is too much traffic that goes through this port. Make sure the ports on the devices that are connected together are both SMF, or both are MMF ports. The number of times a collision occurred before the interface transmitted a frame to the media successfully.Common Causes:Collisions are normal for interfaces configured as half-duplex but must not be seen on full duplex interfaces. << /Subtype /Link Description:show interfaces counters errors. the NIC cards in your machines going to sleep because of inactivity. When the local engineer was unplugging the cable, checking port LEDs etc on the CN side we could see the below, so it was definitely recognising the cable being unplugged even from the switch side only. To support authentication for Telnet with secure shell encryption, use the telnet keyword in the set authentication commands. /Count 23 The Canonical Format Indicator (CFI) bit in the TCI of an 802.1q frame is is set to 0 for the ethernet canonical frame format. >> ehxg!UD|_\\zAo*(EJu4Qa-NC-L%;1::Hr3j`39Xg35t!9 If the switch port receives a lot of late collisions, this usually indicates a duplex mismatch problem and can place the port in an errdisable status in a result. You must apply configuration commands to the appropriate module. The traffic load on the interface is excessive and causes the frames to be discarded. Refer toTroubleshooting Cisco Catalyst Switches to NIC Compatibility Issuesfor details on how to resolve third-party NIC issues. /Rect [162 439.9200134277 349.799987793 451.1400146484] MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, Last clearing of "show interface" counters never, Customers Also Viewed These Support Documents, How to find the port Uptime/Downtime status or utilization in Catalyst 3750 series switches that run Cisco IOS system software. Common Causes:This includes runts, giants, no buffer, CRC, frame, overrun, and ignored counts. The rcv-err counter on a 5K only increments as a result of excessive traffic. For information about setting the IP address and default gateway, see "Configuring the Switch IP Address and Default Gateway.". Large amounts of symbol errors can indicate a bad device, cable, or hardware. In half-duplex environments, it is possible for both the switch and the connected device to sense the wire and transmit at exactly the same time and result in a collision. Port status as seen in the default dashboard color mode. Collisions in a half-duplex environment are normal expected behavior. Make congestion avoidance a priority on your network. If that VLAN is deleted, then the port or interface becomes inactive. OnCatalyst 4000 Seriesrcv-err = the sum of all receive errors, which means, in contrast to the Catalyst 5000, that the rcv-err counter increments when the interface receives an error like a runt, giant or FCS-Err. The switch will reflect that behaviour and you'll see a link go down/up two times. >> >> This is useful to know when a dead interface has failed. If you have physical access to the switch, it can save time to look at the port LEDs which give you the link status or can indicate an error condition (if red or orange). Packet loss causes retransmissions at the transport layer which in turn causes users to experience latency at the application level. uuid:762af52f-ff85-490f-a0c3-36712e66e664 >> You can search known software bugs with the Software Bug Toolkit. Eliminate faulty media convertors: fiber-to-copper, and so on. 03-25-2019 Check the trunking mode on each side of the link. Description:For the Catalyst 6000 Series only - show interfaces counters error.Common Causes:See Platform Exceptions.Platform Exceptions:Catalyst 5000 Seriesrcv-err = receive buffer failures. This can occur when interfaces are configured as layer 2 switchports that use theswitchportcommand. This will give you the last upinformation. The total number of frames whose first transmission attempt was delayed, due to traffic on the network media. /secondaryConcept () Refer toUnderstand and Configure the Unidirectional Link Detection Protocol (UDLD) Featurefor configuration information on UDLD. This chapter consists of these major sections: Using Secure Shell Encryption for Telnet Sessions. This command displays what cards are present in the switch, the version of software they are that run, and what state the modules are in: ok, faulty, and so on. Verify that the connected device operates correctly. >> . In the given example, how long has the port been up? Usually this means there was no packet transfer relative to that entity. This can be caused by a duplex mismatch and physical problems, such as a bad cable, port, or NIC on the attached device. Congestion can lead to packet loss. << If the mismatch occurs between two Cisco devices with the Cisco Discovery Protocol (CDP) enabled, you see the CDP error messages on the console or in the logging buffer of both devices. This example shows how to display information about the ports on a specific module only: This example shows how to display information on an individual port: In addition to displaying the MAC address range for a module using the show module command, you can display the MAC address of a specific port in the switch using the show port mac-address command. Theshow interfacescommand output up to this point is explained here (in order) : up, line protocol is up (connected) - The first uprefers to the physical layer status of the interface. Try the cable in another port or interface if one is available and see if the problem continues. /Subtype /XML These are brief descriptions of when the No dest, (unicast, multicast, and broadcast) counters can increment: If a port is an access port, and the port is connected to an Inter-Switch Link Protocol (ISL) trunk port, the No dest counter is very large since all inbound ISL packets are not forwarded. /CropBox [0 0 612 792] Use theinterface-rangecommand to do this on multiple interfaces at once. These delays are caused by STP, trunking negotiations (DTP), and EtherChannel negotiations (PAgP). You have to manually re-enable the port or interface to take it out the errdisable state unless you configure an errdisable recovery option. This can be an indication of faulty hardware, dot1q or ISL trunking configuration issues. endobj If a port has a solid orange light, this means the software inside the switch shut down the port, either by way of the user interface or by internal processes. /Subtype /Link Use theshow interfaces fastEthernet 6/1 statuscommand to display this: Last input, output - The number of hours, minutes, and seconds since the last packet was successfully received or transmitted by the interface. endobj /T 7 0 R If the link operates at full-duplex, the collision counter is not active. FrameMaker 7.2 /Subtype /Link Using Secure Shell Encryption for Telnet Sessions. /Type /Page 01:05 AM. The total number of frames which experience exactly one collision and are then successfully transmitted. Issue theshow cam agingcommand to check the CAM aging time on the switch. This example shows how to check module status on a Catalyst2948G switch: This example shows how to check module status on a specific module: You can display summary or detailed information on the switch ports using the show port command. Refer toConfiguring Jumbo/Giant Frame Support on Catalyst Switchesfor more information on system requirements, configureand troubleshootfor jumbo and baby giant issues. show tech-support port-channel. << Reduce the switch load if thenumber of packets in this field increase. The STP loop guard feature provides additional protection against Layer 2 forwarding loops (STP loops). An alternative to this command (for Catalyst 6000, 4000, 3550, 2970 2950/2955, and 3750 series switches) is theshow interfacescard-type counters errorscommand which only displays the interface error counters. 11 0 obj Try to find the offending device and remove it from the network. /Subtype /Link To trace the path that packets take through the network, perform this task in privileged mode: Execute IP traceroute to trace the path packets take through the network. This is because the output queue on that interface is overwhelmed by the excess traffic due to the speed mismatch between the inbound and outbound bandwidths. For more information, refer to the UDLD: One-Way link problems section of this document. /Resources 30 0 R The purpose of SPD is to ensure that important control packets, such as routing updates and keepalives, are not dropped when the IP input queue is full. This is because the switch does not know that the connected device is a PC; the switch only knows that the port has changed the state. You must enable CDP on all of the Catalyst 4000 family, Catalyst 5000 family, and Catalyst 6500 series switches in the network. >> You could try and set the keepalive timer on your switchports to something higher than the highest interval seen in your logs, say 20 minutes. << This example shows how to set the logout timer value to 10 minutes: This example shows how to set the logout timer value to 0, preventing idle sessions from being disconnected automatically: Note To use the secure shell encryption (SSH) feature commands, you must be running an encryption image. The common commands used to find this type of information are described in the Most Common Port and Interface Troubleshooting Commands for Cisco IOS section of this document. Someone else in the community shared this with me quite awhile back. They can be defined as any frame bigger than the standard ethernet frame of 1518 bytes (which includes the L2 header and Cyclic Redundancy Check (CRC)). Helpful with the search for software/hardware incompatibilities (with theRelease NotesorSoftware Advisor) and bugs (with theSoftware Bug Toolkit). There are two status elements to detect a link being usable or not: Status and Line Protocol. Port Status : Secure-down. >> . Check or swap the copper or fiber cable. Once you have encapsulation dot1q on a subinterface, you can no longer use that VLAN in the system because the 6500 or 7600 internally allocates the VLAN and makes that sub interface its only member. /Kids [14 0 R 15 0 R] The two devices that cause the late collision never see that each sends until after it puts the entire packet on the network. Description:show interfacesandshow interfaces counters errors. 04:30 PM WK:w9\lBdOeX>V!RKB.GUMrx8<3pfs,nNX`IVw=OYGe; L2]>[1aUGYv4(}d({PJRiPh@fHK49]a9l&]+X.H bVFO4 i8qQf3 Note: To access tools and websites, you must be a registered Cisco client. If collisions increase dramatically, this points to a highly utilized link or possibly a duplex mismatch with the attached device. See the Common Port and Interface Problems section of this document for more information. endstream /Creator (FrameMaker 7.2) %LINK-3-UPDOWN messages in the log show when the port status. The number of packets received incorrectly that has a CRC error and a non-integer number of octets (alignment error). An advantage of PortFast is that this feature suppresses TCNs for a host port. You can also use thespanning-tree portfastcommand per interface, but this requires that you turn off trunking and etherchannel separately to help fix workstation startup delays. There can be a situation where the software is not compatible with the hardware. Swap suspect GBIC with known good GBIC.
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