cisco show port status up down

Failures of any test of a module or port show an 'F' in the test results. 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. Before you can open a Telnet session to the switch, you must first set the IP address (and in some cases the default gateway) for the switch. If so, the port is good. Output queue - The number of packets in the output queue. /Parent 5 0 R If you have a large amount of alignment errors, FCS errors, or late collisions, this can indicate one of these: A common issue with speed/duplex is when the duplex setup are mismatched between two switches, between a switch and a router or between the switch and a workstation or server. Every port in a Layer 2 switch belongs to a VLAN. 3#show ver . Description:show interfaces counters errors. Total output drops - The number of packets dropped because the output queue is full. By using command line(ssh), I can get switch interfaces status like belowjust demo: Cisco-Switch# show int status Port Name Status Vlan Duplex Speed Eth0/1 test_alias connected 1 a-full a-100 Eth0/2 notconnect 1 auto auto Eth0/3 connected 3 a-full a-100 Eth0/4 connected 3 a-full a-100 Eth0/5 potchann linkFlapE 255 auto auto Eth0/6 notconnect 300 auto auto Eth0/7 sfpAbsent routed auto . 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. This is an indication of a bad frame generated by the connected device. In order to troubleshoot auto-negotiation problems it is often recommended to try and hardcodeboth sides. If neither auto-negotiation or hardcode setupseem to work, there can be a problem with the firmware or software on your NIC card. endobj The clear counters command is used to reset interface statistics. /Type /Annot You can need to modify your network topology to reduce the traffic load for this switch. /Rotate 0 Usually this means there was no packet transfer relative to that entity. %PDF-1.4 endobj Check or swap the copper or fiber cable. For more information about how to troubleshoot hardware problems with theshow modulecommand, see the Port or Interface Status is disabled or shutdown or the Hardware Problems sections of this document. Description:show interfacescounter. This situation creates a loop. The line protocol up message shows the data link layer status of the interface and says that the interface can send and receive keepalives. Refer toUnderstanding and Configuring VLAN Trunk Protocol (VTP)for more information on VTP. SeeTable 1for explanations of the error counter output. /Parent 14 0 R This chapter consists of these major sections: Using Secure Shell Encryption for Telnet Sessions. Run a port TDR to test the integrity of the copper cable. 2023 Cisco and/or its affiliates. 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. This indicates that a corruption of the packet occurred within transfer, and Blackwater received the corrupted packet. Collisions in a half-duplex environment are normal expected behavior. A Symbol error means the interface detects an undefined (invalid) Symbol received. You have to manually re-enable the port or interface to take it out the errdisable state unless you configure an errdisable recovery option. Description:show interfacescounter. 9 0 obj 3506 Specify a shorter period of time to get an accurate read (to better detect traffic bursts for example and issue theload-interval interface command. The SSH feature provides security for Telnet sessions to the switch. Avoid daisy-chained hubs whenever possible. Check the physical connection on both sides. Baby Giant frames are just slightly larger than the maximum size of an ethernet frame. /Subtype /Link Eliminate faulty media convertors: fiber-to-copper, and so on. Late collisions can also indicate an Ethernet cable or segment that is too long. An STP loop is created when an STP block port in a redundant topology erroneously transitions to the forwarding state. << 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. uuid:af7b7cc0-33fd-4b39-afce-898b51ab9cfc The two options are single mode fiber (SMF) or multimode fiber (MMF). Navigate to thelink for more information about the commands Recover Errdisable Port State on Cisco IOS Platforms: One common cause of inactive ports on switches that run Cisco IOS is when the VLAN they belong to disappears. >> You can see what modules are installed, as well as the MAC address ranges and version numbers for each module, by using the show module command. Note: If the Deferred Counter error increments on a GigabitEthernet of a Supervisor 720, turn on speed negotiation on the interface as a workaround. For the duplex mismatch scenario, the late collision is seen on the half-duplex side. i feel this command is only for trunks using DTP and not for access ports. /Rect [162 405.8999938965 319.799987793 417.1199951172] If you connect a good cable to two switch ports in the notconnect state, the link light must become green for both ports, and the port status must indicate connected. To use this feature, you must install the application on the client accessing the switch and you must configure SSH the switch. The show interface command displays the administrative and operational status of a switchport, input and output packets, buffer failures, errors, and so on. The Catalyst 6000/4000 does not turn the port light orange when it blocks for STP. Use thespeedandduplexcommands from interface configuration mode to hardcode both sides to 10 or 100 and half or full as necessary. The number of times the receiver on the port is disabled, possibly because of buffer or processor overload. The port moves to the STP forwarding state and creates a loop. These partially functional links can cause problems such as STP loops when the switches involved do not know that the link is partially broken. /Contents 29 0 R The total number of frames whose length is less than 64 octets (which excludes frame bits, but includes FCS) and have a bad FCS value. Check the results ofshow modulefor Catalyst 6000 and 4000 series switches that run Cisco IOS. Rule out any bad patch panel connections or media convertors between source and destination. Note: Variables that can affect routing (for example, load and reliability) are not cleared when the counters are cleared. >> After 16 attempts have been made to send the packet the packet is dropped, and the counter increments. 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. The maximum number of hops an l2trace query will try is 10; this includes hops involved in source tracing. LCP-SW1: Mar 01 09:01:09 GMT: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to up, LCP-SW1: Mar 01 09:01:21 GMT: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to down, LCP-SW1: Mar 01 09:01:28 GMT: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to up. Verify the cable selection. 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. When the receive part (Rx) of the port has its Rx FIFO queue filled and reaches the high water mark, the transmit part (Tx) of the port starts to generate pause frames with an interval value mentioned in it. endobj Share Improve this answer Follow answered May 19, 2016 at 14:08 Ron Maupin 97.5k 26 112 188 To display the active user sessions on the switch, perform this task in privileged mode: Display the currently active user sessions on the switch. Eventually, the block port from the alternate or backup port becomes designated and moves to a forwarding state. 1 0 obj There are two status elements to detect a link being usable or not: Status and Line Protocol. setup auto speed/duplex on one side and 100/Full-duplex on the other side is also a misconfiguration and can result in a duplex mismatch. This total includes frames of all destination types. 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. 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. A common cause is traffic from a high bandwidth link that is switched to a lower bandwidth link or traffic from multiple inbound links that are switched to a single outbound link. When a port is in error-disabled state, it is effectively shut down and no traffic is sent or received on that port. WK:w9\lBdOeX>V!RKB.GUMrx8<3pfs,nNX`IVw=OYGe; L2]>[1aUGYv4(}d({PJRiPh@fHK49]a9l&]+X.H bVFO4 i8qQf3 Other possible causes of data link errors at full-duplex are bad cables, faulty switch ports, or NIC software/hardware issues. This is the command to use on the Catalyst 6000, 4000, 3550, 2950, and and 3750 series. /Dest (G1019856) /Count 23 - last edited on In order to enable the simultaneous use of 10-Gigabit Ethernet and the Gigabit Ethernet SFP interfaces, issue thehw-module uplink select allcommand. Also, if there is a hub connected to the port, collisions between other devices on the hub can cause these errors.Platform Exceptions:Alignment errors are not counted on the Catalyst 4000 Series Supervisor I (WS-X4012) or Supervisor II (WS-X4013). Violation Mode : Shutdown. /keywords () The number of packets received incorrectly that has a CRC error and a non-integer number of octets (alignment error). << For each group of eight ports, the frames that are received are buffered and sent to the common Gigabit Ethernet link to the internal switch fabric. Use theinterface-rangecommand to do this on multiple interfaces at once. /Type /Pages In order to convert the interface from layer 3 mode to layer 2 mode, issue the interface configuration commandswitchport. Common Causes:Broadcast storms and bursts of noise can cause the ignored count to be increased. /Subtype /Link Switch#show inter status. Note: Use this Recover Errdisable Port State on Cisco IOS Platformsfor more information on errdisable status on switches that run Cisco IOS. You can remove some devices from crowded segments to other less populated segments. /Dest (G1063442) Refer toSpanning-Tree Protocol Enhancements using Loop Guard and BPDU Skew Detection Featuresfor more information on the loop guard feature. The STP loop guard feature provides additional protection against Layer 2 forwarding loops (STP loops). /Subtype /Link /Dest (G1029178) The command output displays all network layer (Layer3) devices, such as routers, that the traffic passes through on the way to the destination. Note If you are using Kerberos to authenticate to the switch, you will not be able to use the secure shell encryption feature. 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). (See "Configuring CDP," for information about enabling CDP.) << Try to find the offending device and remove it from the network. For the Cisco IOS system messages format, you can refer to theMessages and Recovery Procedures Guidefor the release of software you run. The traceroute command uses the Time To Live (TTL) field in the IP header to cause routers and servers to generate specific return messages. This article purportedly explains how to find the former, but actually explains how to find the latter. The ping command is configurable from normal executive and privileged executive mode. If the switch overwhelms the Ethernet interface, check the speed and duplex setup. Bad or wrong Gigabit Interface Convertor (GBIC). As the half-duplex side transmits, the full duplex side does not wait its turn and transmits simultaneously which causes a late collision. 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. endobj << This is because they are only detected in transmissions of packets longer than 64 bytes. The cable can have encountered physical stress that causes it to be functional at a marginal level. /Dest (G1019819) Theshow interfaces counters errorscommand is used in Cisco IOS to display the output of the interface errors only. sh ip protocols - all of the dynamic routing /accessLevel (Guest,Customer,Partner) An SX GBIC needs to connect with an SX GBIC. Swap suspect GBIC with known good GBIC. endobj If an egress interface is over-subscribed, it is normal to see output buffer failures that increment along with Out-Discards. When a layer 3 interface is connected to a layer 2 switchport, it is not able to interpret these frames, which results in Input errors, WrongEncap errors, and Input queue drops.
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cisco show port status up down 2023