For more details on the different types of cables/connectors, cable requirements, optical requirements (distance, type, patch cables, and so on. 26 0 R] This is usually seen in half-duplex environments where the carrier is already in use when it tries to transmit a frame. The example shows the log messages that result from a duplex mismatch between two Catalyst 6000 series switches: one that runs CatOS, and the other that runs Cisco IOS. Description:sh interfacescounter. If you have checked or tried the other suggestions in this document (checked speed/duplex, no physical errors on the link, all the traffic is normal valid traffic, and so on), then reducethe unit size that is sent by the application which can help to alleviate this problem. The easiest way on Cisco switches is: show int status This will show you the link status for all ports The 45xx line has also some additional useful commands: show int link which will show you the last time the link was active. This issue is resolved in Cisco IOS release 12.1(19)EA1 or 12.2(18)SE or later. >> A link light does not guarantee that the cable is fully functional. You must enable CDP on all of the Catalyst 4000 family, Catalyst 5000 family, and Catalyst 6500 series switches in the network. 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. If single connection or Step 3 fails with SC connectors, loop the port back to itself (port one RX goes to port one TX). After you issue the command, re-boot the switch or else the output of theshow interface status modulecommand shows the uplink port as inactive. This ensures that the MAC address table (the CAM table) contains the most recent entries. A switch is in down state when there is nothing connected to the port or if its admin shutdown. For information about setting the IP address and default gateway, see "Configuring the Switch IP Address and Default Gateway.". No action is required. The loop guard feature makes additional checks. Number of frames that took longer than two seconds to travel through the switch. This table shows an example of the commands used to configure verify and troubleshoot the errdisable status on switches. This can also occur if a switch is connected to port 0/1 and starts to flood packets to all of its ports to learn MAC addresses. Aging Type : Absolute. Hardcode both ends of the link to full duplex so that the negotiation mismatch can be avoided. Someone else in the community shared this with me quite awhile back. /Type /Annot Trace a Layer 2 path using IPaddresses or IP aliases. 13 0 obj Check the Command Reference for your release of software to verify the availability of this command. After 16 attempts have been made to send the packet the packet is dropped, and the counter increments. endobj Refer toSpanning-Tree Protocol Enhancements using Loop Guard and BPDU Skew Detection Featuresfor more information on the loop guard feature. UDLD can put a port in errdisable state when it detects a unidirectional link. It would be counted on theshow interfaceoutput for the appropriate physical interface. This means it is currently not connected to anything, but it can connect if it has a good connection to another operational device. When the VLAN is already in fast aging, EARL cannot set the VLAN to fast aging, and aging timer set process is blocked. MTU - The Maximum Transmission Unit (MTU) is 1500 bytes for Ethernet by default (for the max data portion of the frame). endobj CDP is useful to detect errors, as well as port and system statistics on nearby Cisco devices. Check the end device with a pingsent from the directly connected switch first, then work your way back port by port, interface by interface, trunk by trunk until you find the source of the connectivity issue. << This total includes only those frames that are subsequently transmitted without error and not affected bycollisions. The same output show up for trunk ports as well as access ports. IOS (tm) C2950 Software (C2950 . << If Rx-No-Pkt-Buff increments and TxPauseFrames also increments, it means that the remote end disregards the pause frames (does not support flow control) and continues to send traffic despite the pause frames. Common Causes:This includes runts, giants, no buffer, CRC, frame, overrun, and ignored counts. This example shows the output of the show users command when local authentication is enabled for console and Telnet sessions (the asterisk [*] indicates the current session): This example shows the output of the show users command when TACACS+ authentication is enabled for console and Telnet sessions: This example shows how to display information about user sessions using the noalias keyword to display the IP addresses of connected hosts: To disconnect an active user session, perform this task in privileged mode: Disconnect an active user session on the switch. Cisco recommends that you disable the unicast flooding because it also ensure that no flooding occurs on the port once the MAC address limit is reached. The number of times the carrier was not present in the transmission.Common Causes:Check for a bad cable. ciscomoderator. After you issue this command, configure the port for any layer 2 properties. 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 . << The cable can have encountered physical stress that causes it to be functional at a marginal level. This kind of source routing is only defined for Token Ring and FDDI. This usually happens because one of the ports of a physically redundant topology (not necessarily the STP block port) no longer receives STP BPDUs. /Length 60 0 R /Dests 10 0 R Sometimes a cable appears to be seated in the jack but is not. When you use either the WS-X6548-GE-TX or WS-X6148-GE-TX modules, there is a possibility that individual port utilization can lead to connectivity problems or packet loss on the surrounding interfaces. /language (en) 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. Small amounts of symbol errors can be ignored. Share Improve this question Follow asked Aug 23, 2015 at 6:13 ae41 Description:show interfaces counters errors. Make sure your L3 addressing on the end device and on the router/ L3 switch is correctly configured. Note: Some switches show a steady orange (amber) light on each port when this happens. This table shows the most common commands used to troubleshoot the port or interface problems on switches that run Cisco IOS System Software on the Supervisor. Description:The number of times the receiver hardware was unable to hand received data to a hardware buffer.Common Cause:The input rate of traffic exceeded the ability of the receiver to handle the data. The | include connected shows only the lines of the output that contain the word "connected". ctsadmin-p.gen It has helped us a lot. The switch does not know that the link ingressdirection is bad (the port thinks that the link is up and works). If collisions increase dramatically, this points to a highly utilized link or possibly a duplex mismatch with the attached device. These messages generally tell you what the mismatch is and where it occurs. The issue is because the traffic load destined for the switch is excessive and causes the frames to be discarded. If the link operates at full-duplex, the collision counter is not active. You can use IP traceroute to identify the path that packets take through the network on a hop-by-hop basis. sh ip traffic - all traffic through the Cisco sh controllers ethernet-controller gi1/0/1 phy - information about the SFP module into a particular port show vlan internal usage - used to show vlan sh inventory raw - in 4924 about stuck SFP seems to be the only way to see. If the VLANs are frequently in fast aging, check the reason for fast aging. >> /Border [0 0 0] >> Eliminate faulty media convertors: fiber-to-copper, and so on. Same behaviour when a PC wakes up from sleep. /Border [0 0 0] If the FCS, CRC, alignment, or runt counters increment, check for a duplex mismatch. See "Working with System Software Images," for the software image naming conventions that are used for the encryption images. The number of frames dropped on an interface because the CFI bit is set. FastEthernet0/0 is up, line protocol is up. 3 0 obj 09-26-2014 This example of theshow run interfacecommand shows the unknown protocol drops on the GigabitEthernet 0/1 interface. When one of the ports in a physically redundant topology no longer receives BPDUs, the STP conceives that the topology is loop free. /Rect [162 473.8800048828 315.8999938965 485.1600036621] Unknown hostIf the host does not exist, an unknown host message is returned. In SPA modules, after you create a sub interface with 802.1Q, the same VLAN is not usable on the switch. Duplex mismatch is a situation where the switch operates at full-duplex and the connected device operates at half-duplex, or vice versa. For Catalyst 3750, 3550, 2970, 2950/2955, 2940, and 2900/3500XL switches use the command show controller ethernet-controller to display traffic counter and error counter output that is similar to theoutput for Catalyst 6000 series switches. 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 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. The 9-micron and 10-micron values refer to the mode-field diameter (MFD), which is the diameter of the portion of the fiber that is light-carrying. In order to see POST results per module, use theshow diagnostics modulecommand. (Year 1993), 1 link ups, last link up on Mon Mar 01 1993, 00:01:37 1 link downs, last link down on Mon Mar 01 1993, 00:03:13. is the year/date not updated due to no NTP or local clock configured? The most common reason for TCNs is client PCs connected directly to a switch. A single broken wire or one shutdown port can cause the problem where one side has a link light, but the other side does not. Traffic that is Layer 2 (L2) switched never makes it to the CPU and is not counted in theshow interfacecounters for the VLAN interface. The Catalyst4912G, 2948G, and 2980G switches are fixed-configuration switches, but are logically modular. 0 Helpful Share Reply johnlloyd_13 Engager Options 09-27-2014 02:01 AM Hi, The command output displays all network layer (Layer3) devices, such as routers, that the traffic passes through on the way to the destination. 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 Impossible to tell. If the Rx still works on the queue, once the interval time expires, the Tx sends a new pause frame again with a new interval value. Displays Cisco Technical Support information about EtherChannels. 18 0 obj endobj endobj /Last 44 0 R 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). All of the devices used in this document started with a cleared (default) configuration. This only happens under stress conditions but can happen with bursts of traffic on several ports. This can happen where you have multiple high-speed ports flowing to a single (usually slower) port. /N 59 0 R For Cisco IOS, you can use the show interfaces command to verify whether the interface is up, line protocol is up (connected) . 23 0 obj /Kids [42 0 R] Alignment errors are due to the frame that is not completely copied to the wire, which results in fragmented frames. 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. /B [27 0 R 28 0 R] l2trace {src-ip-addr} {dest-ip-addr} [detail]. Change the cable and patch panel cord to ensure that the cable and patch cords are not defective. For further information on how to troubleshoot hardware problems on Catalyst switches that run Cisco IOS, navigate to the Cisco Switchessupport pages, choose your platform and look at the Troubleshooting > Hardwaresection. Problems have been seen when you connect to devices manufactured before the IEEE 802.3z standard was ratified. You must either enable or disable link negotiation on both ends of the link. 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. /Type /Pages 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: A high number of CRCs is usually the result of collisions but can also indicate a physical issue (such as cabling, bad interface or NIC) or a duplex mismatch. If either device does not support Gigabit auto-negotiation, disable the Gigabit auto-negotiation, and it forces the link up. The data cannot be transferred to the chip fast enough to keep pace with output rate. /Kids [54 0 R 55 0 R 56 0 R 57 0 R] 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. endobj Interface resets can occur along with the underruns. The half-duplex side only expects packets at certain times, not at any time, and therefore counts packets received at the wrong time as collisions. Port status as seen in the color assist mode. The Rx-No-Pkt-Buff counter can increase on ports when it has blades, such as WS-X4448-GB-RJ45, WS-X4548-GB-RJ45, and WS-X4548-GB-RJ45V. 7 0 obj Use the LEDs on these switches to help you understand the POST results. 24 0 obj ". /Parent 14 0 R The port can be configured to filter 802.1Q tagged frames. Common Causes:This is usually the result of collisions or a physical problem (such as cabling, bad port or NIC) but can also indicate a duplex mismatch. For the Cisco IOS system messages format, you can refer to theMessages and Recovery Procedures Guidefor the release of software you run. As the half-duplex side transmits, the full duplex side does not wait its turn and transmits simultaneously which causes a late collision. Check the trunking mode on each side of the link. /Subtype /Link Problems sometimes occur between Cisco switches and certain third-party NIC cards. Follow the below . When you use an LX/LH GBIC with 62.5-micron diameter MMF, you must install a mode-conditioning patch cord (CAB-GELX-625 or equivalent) between the GBIC and the MMF cable on both the transmit and receive ends of the link. The table describes the LED status indicators for Ethernet modules or fixed-configuration switches: Ensure that both sides have a link. The Layer 2 Traceroute utility does not work with Token Ring VLANs, or when multiple devices are attached to one port via hubs, or when multiple neighbors are on a port. These delays are caused by STP, trunking negotiations (DTP), and EtherChannel negotiations (PAgP). It takes 300msec for the card firmware to notify the software that a 10/100/1000BASE-TX link/port is down. You must apply configuration commands to the appropriate module. 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. Ensure that you have the correct cable for the type of connection you want to make. The pause packets stop when the connected device is able to receive the traffic. For each port on the switch, the command provides a real-time display of the rate at which data is received (Rx) and transmitted (Tx) in terms of kilobits per second (KBits/s), number of packets per second (Pkts/s), and utilization (Util) expressed as a percentage of the total bandwidth available. /Dest (G1045525) 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. If you do not include a specific interface, it will show all the interfaces. This increments when the CRC generated by theLAN station or far-end device that originates the traffic does not match the checksum calculated from the data received.Common Causes:This usually indicates noise or transmission problems on the LAN interface or the LAN itself. For example, a runt, giant, or an FCS-Err does not increment the rcv-err counter. Spanning Tree Protocol (STP) loops can cause serious performance issues that masquerade as port or interface problems. 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. Use theshow mac address-table dynamiccommand or substitute theinterfacekeyword. This command displays the current configuration file of the switch. endobj Make congestion avoidance a priority on your network. See the Common Port and Interface Problems section of this document for more information. 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. These frames are dropped and not propagated onto other ports. /Subtype /Link The number of packets received incorrectly that has a CRC error and a non-integer number of octets (alignment error). The error message is received when the traffic level reaches about 2.5 Mb. In order to resolve this, change the mode of the switch port tostatic accessortrunkas per your requirement. ', Switch#show dtp interfaceDTP information for FastEthernet1/0/1: TOS/TAS/TNS: ACCESS/AUTO/ACCESS TOT/TAT/TNT: UNKNOWN/NEGOTIATE/UNKNOWN Neighbor address 1: 000000000000 Neighbor address 2: 000000000000 Hello timer expiration (sec/state): never/STOPPED Access timer expiration (sec/state): never/STOPPED Negotiation timer expiration (sec/state): never/STOPPED Multidrop timer expiration (sec/state): never/STOPPED FSM state: S1:OFF # times multi & trunk 0 Enabled: no In STP: no, Statistics ---------- 0 packets received (0 good) 0 packets dropped 0 nonegotiate, 0 bad version, 0 domain mismatches, 0 bad TLVs, 0 bad TAS, 0 bad TAT, 0 bad TOT, 0 other 0 packets output (0 good) 0 native, 0 software encap isl, 0 isl hardware native 0 output errors 0 trunk timeouts 1 link ups, last link up on Mon Mar 01 1993, 00:01:37 1 link downs, last link down on Mon Mar 01 1993, 00:03:13, The "sh dtp interface" command shows the same date for all interfaces. The information in this document was created from the devices in a specific lab environment. /Dest (G1024221) 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. Wheb ports or interlaces are shut down as a result of errdisable are referred to as causes in Cisco IOS. Connections for transmit-to-transmit and receive-to-receive do not work. This article purportedly explains how to find the former, but actually explains how to find the latter. NIC Card on your devices. Specify a particular module number to see information on the ports on that module only. Always use either Category 5, Category 5e, or Category 6 UTP for 10/100 or 10/100/1000Mbps connections. 11:42 AM Failures of any test of a module or port show an 'F' in the test results. 5 Checking Port Status and Connectivity 5Checking Port Status and Connectivity This chapter describes how to check switch port status and connectivity on the Catalyst 4500 series switch. 01:05 AM. Rule out any bad patch panel connections or media convertors between source and destination. The numbers given for multimode fiber-optic cable refer to the core diameter. /Producer (Acrobat Distiller 7.0 \(Windows\)) endobj
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. If the switch that deleted the VLAN is a VTP server for the VTP domain, every server and client switch in the domain has the VLAN removed from their VLAN table as well. Description:The number of times that the transmitter has been that run faster than the switch can handle.Common Causes:This can occur in a high throughput situation where an interface is hit with a high volume of traffic bursts from many other interfaces all at once. When a port receives a Symbol, it extracts the 8 bit data from the Symbol (10 bits). If the source and destination belong to multiple VLANs and you specify MAC addresses, you can also specify a VLAN. The port starts to drop the packets when the Tx buffer is full and thus increases the underruns and the output buffer failure counters. This utility determines the path by looking at the forwarding engine tables of the switches in the path. There is a difference in the link failure detection times when you run GigabitEthenet on copper versus GigabitEthernet over fiber. To display the active user sessions on the switch, perform this task in privileged mode: Display the currently active user sessions on the switch. For Cisco IOS, on modular switches like the Cat6000, use the commandshow diagnostics. Fa0/1 connected 1 a-full a-100 10/100BaseTX . >> Note:The Catalyst 6500/6000 series switches do not clear the bit counters of an interface with theclear counterscommand. The two options are single mode fiber (SMF) or multimode fiber (MMF). 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. 9 0 obj Last input nevermeans there was no successful interface packet transfer to other end point or terminal. 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. >> /Subtype /Link Customers Also Viewed These Support Documents. All rights reserved.
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