Collisions can cause runts, FCS, and alignment errors due to the frame notcompletely copied to the wire, which results in fragmented frames. /Rect [162 354.8999938965 288.1799926758 366.1199951172] This is because the output buffer of the interface is overwhelmed by the excess traffic due to the speed mismatch between the inbound and outbound bandwidths. Description:show interfaces counters errors. Share Improve this question Follow asked Aug 23, 2015 at 6:13 ae41 At times the traffic transmission characteristics of the applications used can lead to output buffer problems. /Author (ctsadmin-p.gen) /Contents 29 0 R 22 0 obj Share Improve this answer answered Apr 7, 2015 at 0:27 Ron Trunk 65.6k 5 62 125 Add a comment Your Answer Post Your Answer New here? endobj 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. This utility determines the path by looking at the forwarding engine tables of the switches in the path. Here, the VLAN aging time is already set to fast aging. It also occurs when the hardware hits an oversubscription. 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. Status is whether or not the interface is enabled administratively or if there is a physical connection to another device on the other end. All rights reserved. If neither auto-negotiation or hardcode setupseem to work, there can be a problem with the firmware or software on your NIC card. /Kids [33 0 R 34 0 R 35 0 R 36 0 R 37 0 R 38 0 R 39 0 R 40 0 R 41 0 R] FrameMaker 7.2 endobj /Rect [162 490.9200134277 306.8999938965 502.1400146484] /Type /Annot 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. Giant frames are defined as any frame over the maximum size of an ethernet frame (larger than 1518 bytes) that has a bad FCS. Verify distance and cable used per GBIC as defined in this table. The data cannot be transferred to the chip fast enough to keep pace with output rate. Also, use a sniffer program to analyze packets that come in and out of the router fast Ethernet interface. When the cable is first connected to the port, some of these errors can occur. You can need to modify your network topology to reduce the traffic load for this switch. Bad Port or Module Port or Interface or Module not enabled. 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). 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. endobj FCS error count is the number of frames that were received with a bad checksum (CRC value) in the Ethernet frame. The number of times multiple collisions occurred before the interface transmitted a frame to the media successfully. The first up refers to the physical layer status of the interface. << If a static address has been set up on another port in the same VLAN, and no static address was set up for the receiving port, the packet is dropped. Note:There is a difference between the counter of show interface command output for a physical interface and a VLAN interface.The input packet counters increment in the output ofshow interfacefor a VLAN interface when that packet is Layer 3 (L3) processed by the CPU. The WS-X4448-GB-RJ45, WS-X4548-GB-RJ45, and WS-X4548-GB-RJ45V switching modules have 48 oversubscribed ports in six groups of eight ports each: The eight ports within each group use common circuitry that effectively multiplexes the group into a single, non-block, full-duplex Gigabit Ethernet connection to the internal switch fabric. 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. 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. /Rect [162 456.8999938965 320.8200073242 468.1199951172] The pause packets stop when the connected device is able to receive the traffic. Does the link come up? If a port just acquired a link, there is a very brief (less than one second) period where inbound packets are not forwarded. 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. To identify the next hop, traceroute sends a UDP packet with a TTL value of 2. On a Catalyst 4510R series switch, in order to enable both the 10-Gigabit Ethernet and the Gigabit Ethernet SFP uplink ports, there is an optional configuration. 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. These types of errors increase rapidly, especially when the traffic that passes through that link is high or when it has devices such as servers connected to that interface. 17 0 obj The port starts to drop the packets when the Tx buffer is full and thus increases the underruns and the output buffer failure counters. Make sure the ports on the devices that are connected together are both SMF, or both are MMF ports. For troubleshoot information, see theDeferred Frames (Out-Lost or Out-Discard)section of this document. /PageLabels 8 0 R If the link operates at full-duplex, the collision counter is not active. If any devices in the path are transparent to CDP, l2trace will not be able to trace the Layer 2 path through those devices. Troubleshoot Switch Port and Interface Problems - Cisco 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. To monitor inbound and outbound traffic on the port as displayed by the next output, for unicast, multicast, and broadcast traffic. 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). The Maximum Transmission Unit (MTU) of the data portion of an ethernet frame is 1500 bytes by default. /Rect [162 439.9200134277 349.799987793 451.1400146484] It would be counted on theshow interfaceoutput for the appropriate physical interface. The default CAM aging time is five minutes, which means that the switch flushes the table of learned MAC addresses every five minutes. Theshow modulecommand can indicate faulty, which can indicate a hardware problem. 16 0 obj Look at your logs (if link state logging is enabled) for signs of the interface going down/up. /Rect [162 371.8800048828 250.3800048828 383.1600036621] << Note: There can be differences in the implementation of the counters across various platforms and releases. This statistic counts frames that exceed the configured System MTU, but which can have been increased from 1518 bytes to allow for Q-in-Q or MPLS encapsulations. 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 . To use this feature, you must install the application on the client accessing the switch and you must configure SSH the switch. This document covers reasons that STP can fail, what information to look for to identify the source of the problem, and what kind of design minimizes STP risks. /Subtype /Link Traffic that is Layer 2 (L2) switched never makes it to the CPU and is not counted in theshow interfacecounters for the VLAN interface. /Subtype /Link In order to see POST results per module, use theshow diagnostics modulecommand. The runt counter only incremented when a frame less than 64 bytes was received. For more information, see the "Checking Module Status" section. 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. Description:show interfacescounter. SeeTable 1for explanations of the error counter output. Note: There is, an Out-Discard counter in the Cisco IOSshow interfaces counters errorscommand which is explained inTable 1. Description:show interfacescounter. This indicates that a corruption of the packet occurred within transfer, and Blackwater received the corrupted packet. /Rotate 0 Refer toUnderstand and Configure the Unidirectional Link Detection Protocol (UDLD) Featurefor configuration information on UDLD. If either device has multiple Gigabit ports, connect the ports to each other. An SX GBIC does not link with an LX GBIC. << The operating system can have a bug. 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. Cisco command to show all available ports - The Spiceworks Community Every port on a Layer 3 switch configured to be a L2 switchport must also belong to a VLAN. The remote device is expected to stop / reduce the transmission of packets for the interval time mentioned in the pause frame. Refer toConfiguring and Troubleshooting Ethernet 10/100/1000 MB Half/Full Duplex Auto-Negotiationfor details on how to resolve speed/duplex and auto-negotiation issues. 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. /OpenAction [6 0 R /XYZ null null null] 35 Important Cisco Show Commands You Must Know (Cheat Sheet PDF) Other input-related errors can also cause the input errors count to be increased, and some datagrams can have more than one error. It has helped us a lot. When a frame is received which contains an 802.1Q tag the frame is filtered and this statistic is incremented. Description:show interfaces counters errors. 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. Reduce the switch load if thenumber of packets in this field increase. This means that the port is up as far as Layer 1 (L1) is concerned. Refer to Mode-Conditioning Patch Cord Installation Note for more information. Note:The Catalyst 6500/6000 series switches do not clear the bit counters of an interface with theclear counterscommand. Changes aresavedto the config in Cisco IOS with the write memory command. Ping will return one of the following responses: Normal responseThe normal response (hostname is alive) occurs in 1 to 10 seconds, depending on network traffic. What can cause "FastEthernet is up, line protocol is down" on a Cisco This commanda display the 32-bit and 64-bit error counters per port or interface. Total MAC Addresses : 0. Cisco IOS error counter output forshow interfacesorshow interfaces counters errorsfor the Catalyst 6000 and 4000 Series. PDF Checking Port Status and Connectivity - Cisco Congestion can lead to packet loss. 2 0 obj /Subtype /Link The command you are using is the show interfaces command. Check for loose connections. The reason for this occurrence is because the time to propagate the signal from one end of the network to another is longer than the time to put the entire packet on the network. Theshow interfaces counters errorscommand is used in Cisco IOS to display the output of the interface errors only. << The port LED is set to the orange color and, when you issue the show interfaces command, the port status shows as Errdisabled. 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 Description:show interfaces counters errors. This command displays the current configuration file of the switch. Destination does not respondIf the host does not respond, a no answer message is returned. This happens when new hardware comes out and requires special support from the software. /Type /Annot show counters interfaceshow controllers ethernet-controller. In order to troubleshoot auto-negotiation problems it is often recommended to try and hardcodeboth sides. Support for jumbo and baby giants on Catalyst switches varies by switch platform, sometimes even by modules within the switch. The designated port transmits BPDUs, and the non-designated port receives BPDUs. switch - Cisco Command to display link status - Network Engineering CDP is useful to detect errors, as well as port and system statistics on nearby Cisco devices. Note: For Catalyst 3750, 3550, 2970 , 2950/2955, and 2900/3500XL Series switches use theshow postcommand, which indicates a simple pass or fail for the hw status. endobj endobj In order to resolve this, change the mode of the switch port tostatic accessortrunkas per your requirement. Normally the deferred frames are the number of frames that have been transmitted successfully after waiting for the media, because the media was busy. 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. 24 0 obj Look for broken or lost pins on connectors. This can be an indication of faulty hardware, dot1q or ISL trunking configuration issues. By default, all layer 2 ports are indynamic desirablemode, so the layer 2 port tries to form a trunk link and sends out DTP packets to the remote device. Swap the GBIC (if removable) for fiber connections. The information in this document was created from the devices in a specific lab environment. It takes 300msec for the card firmware to notify the software that a 10/100/1000BASE-TX link/port is down. Giant frames or frames received that exceed the maximum IEEE 802.3 frame size (1518 bytes for non-jumbo Ethernet) and have a bad Frame Check Sequence (FCS). Number of frames that took longer than two seconds to travel through the switch. Description:show interfaces. For example, with the WS-X4448-GB-RJ45 10/100/1000 switching module, you can connect ports from different groups, such as ports 4, 12, 20, or 30 (in any order), before you connect ports from the same group, such as ports 1, 2, 3, 4, 5, 6, 7, and 8. %LINK-3-UPDOWN messages in the log show when the port status. Avoid daisy-chained hubs whenever possible. This is helpful to use to determine whether a misconfiguration of the mod/port or interface can cause a problem. endobj Description:show interfacesandshow interfaces counters errors. Use theshow mac address-table dynamiccommand or substitute theinterfacekeyword. The interaface also shows a UP/UP state. endobj /accessLevel (Guest,Customer,Partner) Share Improve this answer Follow answered May 19, 2016 at 14:08 Ron Maupin 97.5k 26 112 188 An obvious but sometimes overlooked cause of port connectivity failure is an incorrect configuration on the switch. 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. If the frames received on any group exceeds the bandwidth of 1 Gbps, the device starts to drop the frames. In order to convert the interface from layer 3 mode to layer 2 mode, issue the interface configuration commandswitchport. The port can be configured to filter 802.1Q tagged frames. 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. Description:show interfacescounter. /P 6 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. There can be a situation where the software is not compatible with the hardware. You must either enable or disable link negotiation on both ends of the link. 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. There are other causes for late collisions besides duplex mismatch, but this is one of the most common reasons. . 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. You can use this utility from a switch that is not in the Layer 2 path between the source and the destination; however, all of the switches in the path, including the source and destination, must be reachable from the switch. A key size with a larger number provides higher security but takes longer to generate. No, it always shows this same date and time for all the interfaces (1993) even though the switch is configure with the correct date and time. /Border [0 0 0] 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. 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). After you issue the command, re-boot the switch or else the output of theshow interface status modulecommand shows the uplink port as inactive. /Type /Metadata This example of theshow run interfacecommand shows the unknown protocol drops on the GigabitEthernet 0/1 interface. ), how to connect the different cables, and which cables are used by most Cisco switches and modules, refer to Catalyst Switch Cable Guide . /T 7 0 R You can use IP traceroute to identify the path that packets take through the network on a hop-by-hop basis. Connections for transmit-to-transmit and receive-to-receive do not work. To display summary information on all of the ports on the switch, enter the show port command with no arguments. Note: On the Catalyst 4503, 4506, and 4507R series switches, this capability is automatically enabled. 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. 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. Traceroute starts by sending a User Datagram Protocol (UDP) datagram to the destination host with the TTL field set to 1. PDF Checking Port Status and Connectivity - cisco.com For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Port Status and Configuration - Hewlett Packard Enterprise /Border [0 0 0] The number of times the carrier was not present in the transmission.Common Causes:Check for a bad cable. The number of packets received incorrectly that has a CRC error and a non-integer number of octets (alignment error). In order to enable the simultaneous use of 10-Gigabit Ethernet and the Gigabit Ethernet SFP interfaces, issue thehw-module uplink select allcommand. But in full duplex environments the issue occurs when the excessive load is destined for the switch. 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. For Cisco IOS, use theshow interfacescard-type {mod/port}trunkcommand to verify the trunking configuration and Native VLAN. When a device is connected to a switchport ..%LINK-3-UPDOWN messages in the log show when the port status. After 16 attempts have been made to send the packet the packet is dropped, and the counter increments. The alternative is to contact the vendor for software/hardware upgrade for IEEE 802.3z Gigabit auto-negotiation support. The excessive collisions counter increases after 16 consecutive late collisions have occurred in a row. 6. /Last 44 0 R Refer toInterface/Module Connectivity Problemsfor more information on oversubscription. This is an indication of a bad frame generated by the connected device. switch# show vtp status VTP Version : 1 Configuration Revision : 0 . The mode-conditioning patch cord prevents the over use of the receiver for short lengths of MMF and reduces differential mode delay for long lengths of MMF. Use theshow interfaces counters errorcommand to look at OutDiscards. >> Reduce the traffic load on the interface if you see the number of packets increase in these fields. FastEthernet0/0 is up, line protocol is up. For more details on the different types of cables/connectors, cable requirements, optical requirements (distance, type, patch cables, and so on. << Make sure the port or module has not been disabled or powered down for some reason. To apply configuration commands to a particular port, you must specify the appropriate logical module. 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. /N 59 0 R 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. Violation Mode : Shutdown. Large amounts of symbol errors can indicate a bad device, cable, or hardware. Your network can send too many packets through this port for the port to handle at its current speed/duplex setup. The resolution is that ordinarily the system recovers automatically. The counter also increments when the destination address of the packet is learned on the port that the packet was received on. 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. >> Is there a command that will show information as to how long that port has been in an "up" state? (See "Configuring CDP," for information about enabling CDP.) 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. 0 Helpful Share Reply johnlloyd_13 Engager Options 09-27-2014 02:01 AM Hi, Most switches have some way to track the packets and errors that occur on a port or interface. HWOw6SE4[ilX}{HPV]~Pz+g f~3Qk6V-s*/|l
Km2NF%~IbQ9-t&39/Y-.L6yI*->N Normally, such a condition is temporary, dependent upon transient peak loads within the system. Also you can use (it is disruptive for the port): test cable-diagnostics tdr interface xx/yy and then Also, dependent upon the hardware and software, some switch platforms increment port and interface error counters as a result. /Type /Annot Switch#show port-security interface fastEthernet 0/1 Port Security : Disabled. This usually happens because one of the ports of a physically redundant topology (not necessarily the STP block port) no longer receives STP BPDUs. Command: show startup-configuration Description: This command is the same as the above show running-configuration command except this will output the configuration that is stored in NVRAM.
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