cisco show port status up down

/CreationDate (D:19990615140519Z) The frames received that are smaller than the minimum IEEE 802.3 frame size of 64 bytes (which excludes frame bits but includes FCS octets) that are otherwise well formed.Common Causes:Check the device that sends out these frames. The maximum number of hops an l2trace query will try is 10; this includes hops involved in source tracing. In many cases, this is the result of a bad NIC. 2900/3500XL only.The number of times that a port received a packet from the network, but the switch did not have the resources to receive it. 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. The interaface also shows a UP/UP state. If the link operates at full-duplex, the collision counter is not active. For example, on a Catalyst2948G series switch, the 24Fast Ethernet ports belong logically to module 2. The idea is that when a topology change occurs, this value is necessary to flush the CAM table faster, to compensate for the topology change. If the amount of data received for a port begins to exceed buffer capacity, flow control sends pause frames to the remote port to temporarily stop traffic and prevent frame loss. Wheb ports or interlaces are shut down as a result of errdisable are referred to as causes in Cisco IOS. This example shows the basic usage of the traceroute command: This example shows how to perform a traceroute with six queries to each hop with packets of 1400bytes each: Catalyst 4500 Series Software Configuration Guide, 7.5, Configuring the Switch IP Address and Default Gateway, Configuring Ethernet and Fast Ethernet Switching, Configuring Fast EtherChannel and Gigabit EtherChannel, Configuring Spanning Tree PortFast, BPDU Guard, BPDU Filter, UplinkFast, BackboneFast, and Loop Guard, Configuring VLAN Trunks on Fast Ethernet and Gigabit Ethernet Ports, Configuring Dynamic VLAN Membership with VMPS, Catalyst 4500 Series, Catalyst 2948G and Catalyst 2980G Switches Software Configuration Guide, 7.5, "Configuring the Switch IP Address and Default Gateway. Does the port come up? That woud mean that the switchport would not go down even after not getting a response from the connected device for 20 minutes, if that is what you want: In addition, if you just want to get rid of the messages in your log, you can configure the logging discriminator below: logging discriminator LINKSTATUS severity drops 3 facility drops LINK mnemonics drops UPDOWN, logging buffered discriminator LINKSTATUS 100000logging console discriminator LINKSTATUSlogging monitor discriminator LINKSTATUSlogging host 192.168.100.10 discriminator LINKSTATUS, 05-11-2020 When you look at show interfacecard-type {slot/port}statuscommand for Cisco IOS: Theshow loggingcommand for Cisco IOS also display the error messages (exact message format varies) that relate to the errdisable state. For Cisco IOS, you can use the show interfaces command to verify whether the interface is up, line protocol is up (connected) . In order to troubleshoot auto-negotiation problems it is often recommended to try and hardcodeboth sides. Common Causes:Check for a bad cable. >> It takes 300msec for the card firmware to notify the software that a 10/100/1000BASE-TX link/port is down. If single connection or Step 3 fails with SC connectors, loop the port back to itself (port one RX goes to port one TX). Other possible causes of data link errors at full-duplex are bad cables, faulty switch ports, or NIC software/hardware issues. STP blocks on the port and prevents any loops (port one receive (RX) goes to port two transmit (TX), and port one TX goes to port two RX). Fa0/1 connected 1 a-full a-100 10/100BaseTX . Common Causes:This includes runts, giants, no buffer, CRC, frame, overrun, and ignored counts. In order to overcome this situation, manually configure the speed and duplex, as well as disable the flow control, if required. Theshow modulecommand can indicate faulty, which can indicate a hardware problem. For this reason, they were discarded by the switch. endobj Check the physical connection on both sides. The traffic load for this switch is excessive and causes the frames to be discarded. /Length 60 0 R The command show diagnostic was introduced in 12.1(11b)E for the Catalyst 6000 series and show diagnostics (with an s ) was introduced in for Catalyst 4000 Series. You can show all the interfaces in a Cisco switch with the same command you are using. Always check the cable for marginal damage or failure. /Rect [162 439.9200134277 349.799987793 451.1400146484] There are two status elements to detect a link being usable or not: Status and Line Protocol. Therefore, this sum cannot balance with the sum of enumerated input error counts. A jabber is a frame longer than 1518 octets (which exclude frame bits, but include FCS octets), which does not end with an even number of octets (alignment error) or has a bad FCS error. /Rect [162 320.8800048828 286.5599975586 332.1600036621] 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. << /V 27 0 R 03-01-2019 In order to check to see how long the port is in Up or Down status, use the show interfaces [interface id] command. Hi Nima, "show ip interface" command would show you the L1 and L2 status of the interface, instead "show port-security interface" would show you the status of the port security, now if you enable port security on an interface where there is a host connected the port status would be in "Secure-up", but if there is nothing connected to that interface, then the port status would be "Secure-down . Theshow interfacescard-type {slot/port}counterscommand is used when you run Cisco IOS on the Supervisor. This is usually seen in half-duplex environments where the carrier is already in use when it tries to transmit a frame. These delays are caused by STP, trunking negotiations (DTP), and EtherChannel negotiations (PAgP). Maximum MAC Addresses : 1. The show interfaces status cli command shows you all interfaces. This counter indicates the internal state of the Switching ASICs on the Supervisor and does not necessarily indicate an error condition. /N 28 0 R For example, if you have two routers connected and you disable CDP on one router interface, this results in unknown protocol drops on that interface. If BPDUs are not received on a non-designated port, and loop guard is enabled, that port is moved into the STP loop-inconsistent block state, instead of the listening / learning / forwarding state. If a router finds a TTL value of 1 or 0, it drops the datagram and sends back an Internet Control Message Protocol (ICMP) time-exceeded message to the sender. The numbers given for multimode fiber-optic cable refer to the core diameter. Acrobat Distiller 7.0 (Windows) Change the cable and patch panel cord to ensure that the cable and patch cords are not defective. As the half-duplex side transmits, the full duplex side does not wait its turn and transmits simultaneously which causes a late collision. The total number of frames received whose length exceeds the System MTU, yet which have good FCS values. All of the devices used in this document started with a cleared (default) configuration. The use of this feature can help you identify difficult to find unidirectional link problems. In order to check to see how long the port is in, Last input 00:00:41, output 00:00:00, output hang never, Last input never, output never, output hang never. 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. Alignment errors are the number of frames received that do not end with an even number of octets and have a bad CRC. Collisions in a half-duplex environment are normal expected behavior. This example shows the source and destination MAC addresses specified, with no VLAN specified but with the detail option specified. This is only required if end-devices such as older Gigabit NICs are used which cannot support IEEE 802.3z. CISCO MDS - Useful 'Show' Commands CONFIG: show startup-config show running-config show running-config diff show run |include host|gateway|ntp|fcdomain|http|telnet|zoneset|vsan show start |include host|gateway|ntp|fcdomain|http|telnet|zoneset|vsan show install all status show switchname show wwn switch show switch summary show version - last edited on Hardcode both ends of the link to full duplex so that the negotiation mismatch can be avoided. 5 minute input/output rate - The average input and output rate seen by the interface in the last five minutes. The number of failed buffers and the number of buffers swapped out.Common Causes:A port buffers the packets to the Tx buffer when the rate of traffic switched to the port is high and it cannot handle the amount of traffic. The messages are generated by the switch. >> endobj 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. >> Dispersion-shifted single-mode fiber-optic cable. Generally, a one percent ratio of errors to total traffic is acceptable for half-duplex connections. 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. Description:show interfaces counters errors. Encryption commands are set crypto key rsa, clear crypto key rsa, and show crypto key. Warning: Category 5e and Category 6 cables can store high levels of static electricity because of the dielectric properties of the materials used in their construction. This example shows how to ping a remote host from normal executive mode: This example shows how to ping a remote host using the -s option: This example shows how to enter a ping command in privileged mode specifying the number of packets, the packet size, and the timeout period: The Layer 2 Traceroute utility allows you to identify the physical path that a packet takes from a source to a destination. By default, software processes inside the switch can shut down a port or interface if certain errors are detected. The controller senses the wire and checks if it is not busy before it transmits.Common Causes:This is normal on an half-duplex Ethernet segment. 06:17 PM show tech-support port-channel. For a single interface.Cisco-Switch#show int g1/0/7 Last input never, output 1y25w, output hang never, For all interfaces.Cisco-Switch#show int | in Last | proto, I think this command will give u the uptime of that interface. In order to convert the interface from layer 3 mode to layer 2 mode, issue the interface configuration commandswitchport. The traceroute facility determines the address of the first hop by examining the source address field of the ICMP time-exceeded message. 3 0 obj Note: If the Deferred Counter error increments on a GigabitEthernet of a Supervisor 720, turn on speed negotiation on the interface as a workaround. Investigate these common causes of output buffer failures: Inferior Speed/Duplex for the Amount of Traffic. Check Connected Modules Checking Interface Status Displaying PORT SET ENABLED LED Status Displaying MAC Addresses Using Telnet Checking Cable Status Using Time Domain Reflectometer Changing the Logout Timer Monitoring User Sessions Using Ping Using IP Traceroute Using Layer 2 Traceroute Configuring ICMP This is the command to use on the Catalyst 6000, 4000, 3550, 2950, and and 3750 series. Basically, up/down means the port is available for a cable/connection, but doesn't have one. endobj It would be counted on theshow interfaceoutput for the appropriate physical interface. Cisco IOS has the option to use theglobal spanning-tree portfast defaultcommand to automatically apply portfast to any interface configured as a layer 2 access switchport. >> This error message is caused when a frame is transmitted, and the local buffer of the controller chip local buffer receives insufficient data. Telnet sessions initiated from the switch cannot be encrypted. Also you can use (it is disruptive for the port): test cable-diagnostics tdr interface xx/yy and then (Protocol down/up). The result is the runt counter now increments inshow interfaces, along with the fragments counter inshow interfaces counters errorswhen a frame <64 bytes with a bad CRC is received.Cisco Catalyst 3750 Series SwitchesIn releases prior to Cisco IOS 12.1(19)EA1, when dot1q is used on the trunk interface on the Catalyst 3750, runts can be seen onshow interfacesoutput because valid dot1q encapsulated packets, which are 61 to 64 bytes and include the q-tag, are counted by the Catalyst 3750 as undersized frames, even though these packets are forwarded correctly. The ports need to be in agreement as to what format they use on the link, or they do not understand each other. Theshow interfaces counters errorscommand is used in Cisco IOS to display the output of the interface errors only. /Threads [7 0 R] Check the physical connection on both sides. >> /Border [0 0 0] If you have device A connected to device B over a Gigabit link, and the link does not come up, perform this procedure. This article purportedly explains how to find the former, but actually explains how to find the latter. Aging Type : Absolute. Description:show interfacescounter. The documentation set for this product strives to use bias-free language. >> /Border [0 0 0] I usually start first with the following command: Switch0# show interfaces status Port Name Status Vlan Duplex Speed Type Fa0/1 connected 1 auto auto 10/100BaseTX /Border [0 0 0] 21 0 obj The counter also increments when the destination address of the packet is learned on the port that the packet was received on. If the VLANs are frequently in fast aging, check the reason for fast aging. If this counter increments, it is an indication of a wiring problem, an excessively loaded network, or a duplex mismatch. All rights reserved. Excessive errors for certain counters usually indicate a problem. /Rect [162 422.8800048828 257.2799987793 434.1600036621] For more information, see the "Checking Module Status" section. Port Overview The Switch Ports section shows a basic view of the status of all switch ports. Note: Refer toUsing Portfast and Other Commands to Fix Workstation Startup Connectivity Delaysfor more information how to fix startup delays. endobj Normally you can identify this situation if the port has many packet errors, or the port constantly flaps (loses and regains link). Size/max means the current number of frames in the queue/the max number of frames the queue can hold before it is full and must start to drop the frames. If a packet cannot be completely received because the switch is out of packet buffers, this counter is incremented once for every dropped packet. That's how they behave. /Type /Metadata Reduce the traffic load on the interface if there are incrementsin the number of packets in this field. For example, you can look attheMessages and Recovery Proceduresfor Cisco IOS Releases. Reconfigure the trunk encapsulation on both devices. IOS (tm) C2950 Software (C2950 . Text /Subtype /Link /First 12 0 R If you turn the trunking mode to on (as opposed to auto or desirable) for one port and the other port has the trunking mode set to off, they are not able to communicate. On one of my 3750's ports that have never gone down show a 1993 timestamp, ports that have gone up/down have a recent (correct) date, 1 link ups, last link up on Sun Feb 28 1993, 16:01:20, 4 link ups, last link up on Tue Dec 02 2014, 14:51:11. You can upgrade10Mbps links to 100Mbps or Gigabit Ethernet links when possible. Destination unreachableIf the default gateway cannot reach the specified network, a destination unreachable message is returned. New here? When you have devices that need to carry a large amount of traffic through that interface, consider the use of one port of each group so that the common circuitry that shares a single group is not affected by this amount of traffic. The command output displays all network layer (Layer3) devices, such as routers, that the traffic passes through on the way to the destination. >> endobj New here? The traffic load on the interface is excessive and causes the frames to be discarded. Refer to Mode-Conditioning Patch Cord Installation Note for more information. A cable can be just good enough to connect at the physical layer, but it corrupts packets as a result of subtle damage to the wiring or connectors. (It still must be far less than one percent of the frames received. /ModDate (D:20110317115332Z) /Type /Pages This can happen in these situations: If a hub is connected to port 0/1, and a workstation connected to the hub transmits a packets to another workstation connected to the hub, port 0/1 does not forward this packet anywhere because the destination MAC resides on the same port. The number of times the carrier was not present in the transmission.Common Causes:Check for a bad cable. If collisions increase dramatically, this points to a highly utilized link or possibly a duplex mismatch with the attached device. This tests each device and verifies that the Gigabit interface functions correctly. Share Improve this answer Follow answered Sep 21, 2011 at 10:46 Theo 1,632 12 12 Add a comment 3 This might be a very late reply but here's what I understood so far: The interface status has two parts to it: In privileged executive mode, the ping command allows you to specify the packet size, packet count, and the wait time. The runt counter only incremented when a frame less than 64 bytes was received. This issue is resolved in Cisco IOS release 12.1(19)EA1 or 12.2(18)SE or later. Cisco ethernet interfaces are normally down / down if they don't have a link. Unknown protocol drops are normally dropped because the interface where these packets are received is not configured for this type of protocol, or it can be any protocol that the router does not recognize. In switches that support both L3 interfaces and L2 switchport, the message"Command rejected: [interface] not a switching port"displays when you try to enter a command related to layer 2 on a port that is configured as a layer 3 interface. 1000BASE-T and 1000BASE-X Port Cabling Specifications, Category 5 UTP Category 5e UTP Category 6 UTP, 722 ft (220 m) 902 ft (275 m) 1640 ft (500 m) 1804 ft (550 m), 1804 ft (550 m) 1804 ft (550 m) 1804 ft (550 m) 6.2 miles (10 km). In order to resolve this issue, complete these steps: Make sure Cisco Discovery Protocol (CDP) runs between the switch and router and both can see each other. Move the cable to a known good port to troubleshoot a suspect port or module. << The results of a duplex mismatch are extremely slow performance, intermittent connectivity, and loss of connection. You can change the topology to route frames differently. For the Cisco IOS system messages format, you can refer to theMessages and Recovery Procedures Guidefor the release of software you run. To support authentication for Telnet with secure shell encryption, use the telnet keyword in the set authentication commands. This utility determines the path by looking at the forwarding engine tables of the switches in the path. Theshow counters interfacecard-type {slot/port}command was introduced in Cisco IOS software version 12.1(13)E for the Catalyst 6000 series only, it offers even more detailed statistics for ports and interfaces. If a port just acquired a link, there is a very brief (less than one second) period where inbound packets are not forwarded. Trunk can come up after you disable and enable the switchport, but eventually the switchport can go down again. (Line down/up), Layer 2 goes down and then up. This only happens under stress conditions but can happen with bursts of traffic on several ports. >> Five hundred and twelve bit-times corresponds to 51.2 microseconds on a 10 Mbit/s system. There is a difference in the link failure detection times when you run GigabitEthenet on copper versus GigabitEthernet over fiber. This high load of traffic oversubscribes the ports, which exhausts the input buffers and causes the Rx-No-Pkt-Buff counter and input errors to increase rapidly. If unicast flooding is enabled on that port, it can cause the port to shut down after a reboot. Description:show interfacesand show interfaces counters errors. In the given example, how long has the port been up? Description:show interfaces. Sometimes a cable appears to be seated in the jack but is not. /iaPath () /keywords () Status is whether or not the interface is enabled administratively or if there is a physical connection to another device on the other end. If either device does not support Gigabit auto-negotiation, disable the Gigabit auto-negotiation, and it forces the link up. Runt frames or frames received that are less than 64 bytes (which includes the FCS bits and excludes the frame header) and have either an FCS error or an alignment error. /title (Checking Port Status and Connectivity) Violation Mode : Shutdown. Distances are based on fiber loss. Find answers to your questions by entering keywords or phrases in the Search bar above. This example shows you how to display the MAC address of a specific port: This example shows you how to display the MAC addresses of all ports on a module: You can display the capabilities of any port in a switch using the show port capabilities command. In the example, under the show interfaces FastEthernet0/1 command, look at a line that shows something such as: Last input 00:00:41, output 00:00:00, output hang never. endobj The number of packets received incorrectly that has a CRC error and a non-integer number of octets (alignment error). Specify a particular module number to see information on the ports on that module only. /B [27 0 R 28 0 R] The Catalyst 6000/4000 does not turn the port light orange when it blocks for STP. The bottom line is that even if you configure the interface to recover from errdisable the problem reoccurs until the root cause is determined. If an asterisk (*) appears after the throttles counter value, it means that the interface is throttled at the time the command is run.Common Causes:Packets which can increase the processor overload include IP packets with options, expired TTL, non-ARPA encapsulation, fragmentation, tunnels, ICMP packets, packets with MTU checksum failure, RPF failure, IP checksum and length errors. Network or host unreachableIf there is no entry in the route table for the host or network, a network or host unreachable message is returned. /Border [0 0 0] No destination broadcast are the number of broadcast packets that the port did not forward to any other ports. These drops are not obvious as they are dropped at the internal ASIC rather than the actual interfaces. If the port is in a VLAN by itself, and no other ports on the switch belong to that VLAN, all inbound packets are dropped and the counter increments. Do not disable auto-negotiation between switches unless absolutely required to do so, as physical layer problems can go undetected, which results in STP loops. allen police scanner, liquid smoke injection recipes, advantages and disadvantages of plain film radiography,

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cisco show port status up down