If you have the output of the supported commands from your Cisco device, you can use Cisco CLI Analyzer to display potential issues and fixes. 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 . Typically, the output drops can occur if QoS is configured and does not provideenough bandwidth to certain class of packets. Generally, a one percent ratio of errors to total traffic is acceptable for half-duplex connections. >> l2trace {src-ip-addr} {dest-ip-addr} [detail]. IOS (tm) C2950 Software (C2950 . 3 0 obj endobj These messages generally tell you what the mismatch is and where it occurs. Note:The Catalyst 6500/6000 series switches do not clear the bit counters of an interface with theclear counterscommand. Use the LEDs on these switches to help you understand the POST results. Customers Also Viewed These Support Documents. Note: For fiber connections, make sure the transmit lead of one port is connected to the receive lead of the other port. The number of frames dropped on an interface because the CFI bit is set. Try the following commands. You can show all the interfaces in a Cisco switch with the same command you are using. Fast aging temporarily sets the CAM aging time to the number of seconds that the user specifies, and is used in conjunction with the Topology Change Notification (TCN) process. /Annots [16 0 R 17 0 R 18 0 R 19 0 R 20 0 R 21 0 R 22 0 R 23 0 R 24 0 R 25 0 R Port Status and Configuration - Hewlett Packard Enterprise Once you know the switch actually has the MAC address of the device in the CAM table, determine whether this device is on the same or different VLAN from where you try to ping. Theshow counters interfacecommand was introduced in software version 12.1(13)E for the Catalyst 6000 series only anddisplays 32-bit and 64-bit error counters. The error message is received when the traffic level reaches about 2.5 Mb. Descriptions:show interfacescounter. This only happens under stress conditions but can happen with bursts of traffic on several ports. Refer toTroubleshooting Cisco Catalyst Switches to NIC Compatibility Issuesfor details on how to resolve third-party NIC issues. When a device is connected to a switchport ..%LINK-3-UPDOWN messages in the log show when the port status. 17 0 obj Note:Some port LEDs of the platform work differently in regard to STP. Description:show interfacescounter. The designated port transmits BPDUs, and the non-designated port receives BPDUs. This ensures that the MAC address table (the CAM table) contains the most recent entries. /Rect [162 405.8999938965 319.799987793 417.1199951172] Use theshow interfacescard-type {slot/port}switchportcommand along withshow vlanto verify. 06:17 PM Description:show interfacescounter. This example shows the source and destination MAC addresses specified, with no VLAN specified but with the detail option specified. For example, a runt, giant, or an FCS-Err does not increment the rcv-err counter. In order to overcome this situation, manually configure the speed and duplex, as well as disable the flow control, if required. If a packet was received on port 0/1, with destination MAC address X, and the switch has already learned that MAC address X resides on port 0/1, it increments the counter and discards the packet. For more information, see the "Checking Module Status" section. No destination multicast are the number of multicast packets that the port did not forward to any other ports. Use these resources to familiarize yourself with the community: Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. Common Causes:Check for a bad cable. Swap the GBIC (if removable) for fiber connections. endobj The causes for this range from EtherChannel misconfiguration that causes a PAgP flap, duplex mismatch, BPDU port-guard and portfast configured at the same time, UDLD that detects a one-way link, and so on. Collisions in a half-duplex environment are normal expected behavior. Move the cable to a known good port to troubleshoot a suspect port or module. /MediaBox [0 0 612 792] 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. You can search known software bugs with the Software Bug Toolkit. Switch#show inter status. If the segment is shared, other devices on this segment can transmit so much that the switch has no opportunity to transmit. Last input nevermeans there was no successful interface packet transfer to other end point or terminal. /Parent 14 0 R Learn more about how Cisco is using Inclusive Language. /Border [0 0 0] endobj 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. 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. Interface up/down: why? - Cisco SeeTable 1for explanations of the error counter output. For example, if a large amount of traffic flow comes in on a gigabit interface and is switched out to a 100Mbps interface, this can cause output drops to increment on the 100Mbps interface. traceroute [-n] [-w wait_time] [-i initial_ttl] [-m max_ttl] [-p dest_port] [-q nqueries] [-t tos] host [data_size]. /R [41 63 585 621] /Parent 5 0 R 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. The show interfaces status cli command shows you all interfaces. /ModDate (D:20110317115332Z) It depends on the amount of the packets that are stored in the Rx FIFO buffer of the module ASIC. Specify a shorter period of time to get an accurate read (to better detect traffic bursts for example and issue theload-interval interface command. New here? Trunk can come up after you disable and enable the switchport, but eventually the switchport can go down again. Reduce the switch load if thenumber of packets in this field increase. Use theshow run interfacecommand and check to see if the interface is in ashutdownstate: If the port goes into shutdown mode immediately after a reboot of the switch, the probable cause is the port security setup. A dribble bit error indicates that a frame is slightly too long.Common Causes:This frame error counter is incremented for informational purposes, since the switch accepts the frame. Description:show interfacescounter. These types of errors on the interface are related to a traffic problem with the ports oversubscribed. The most common reason for TCNs is client PCs connected directly to a switch. This can be caused by a duplex mismatch and physical problems, such as a bad cable, port, or NIC on the attached device. The runt counter only incremented when a frame less than 64 bytes was received. This can occur when interfaces are configured as layer 2 switchports that use theswitchportcommand. 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. Category 3 copper cable can be used for 10 Mbps unshielded twisted pair (UTP) connections but must never be used for 10/100 or 10/100/1000Mbps UTP connections. /Type /Annot Issue theshow cam agingcommand to check the CAM aging time on the switch. 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. Unknown hostIf the host does not exist, an unknown host message is returned. This counter is updated only when packets are process switched, not when packets are fast switched. It would be counted on theshow interfaceoutput for the appropriate physical interface. >> At times the traffic transmission characteristics of the applications used can lead to output buffer problems. /Dest (G1019819) /Nums [0 32 0 R] << >> The number of valid size frames with Frame Check Sequence (FCS) errors but no frame errors. The port starts to drop the packets when the Tx buffer is full and thus increases the underruns and the output buffer failure counters. /Type /Metadata Check the physical connection on both sides. Specify a particular module number to see information on the ports on that module only. To identify a Layer 2 path, perform one of these tasks in privileged mode: l2trace {src-mac-addr} {dest-mac-addr} [vlan] [detail]. For more details on the different types of cables/connectors, cable requirements, optical requirements (distance, type, patch cables, and so on. If Rx-No-Pkt-Buff is zero or does not increment and the TxPauseFrames counter increments, it indicates that our switch generates pause frames and the remote end obeys, hence Rx FIFO queue depletes. /Last 44 0 R As a result, the message has a severity level of 3. 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. 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. Make sure your L3 addressing on the end device and on the router/ L3 switch is correctly configured. /CreationDate (D:19990615140519Z) 8 0 obj If you do not include a specific interface, it will show all the interfaces. It is caused by protocols that are not understood by the router/switch. Does the port come up? If either device has multiple Gigabit ports, connect the ports to each other. In SPA modules, after you create a sub interface with 802.1Q, the same VLAN is not usable on the switch. >> The number of received packets ignored by the interface because the interface hardware ran low on internal buffers. On a Layer 2 switch we can check the status and various other counters and metrics for each physical ethernet interface or for every interface on the device. 1 0 obj TCNs and fast aging are fairly rare. For possible issues related to Field Notices, refer toField Noticesfor LAN and ATM Switches. 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. Information is displayed about all Catalyst 4000 family, Catalyst 5000 family, and Catalyst 6500 series switches that are in the path from the source to the destination. /CropBox [0 0 612 792] /I 31 0 R Check the cable, or other computer. 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: 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. 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. Without attenuators, the minimum link distance is 24.9 miles (40 km). Undersize = frame < 64bytes. 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. Also refer to the sectionInput Errors on a Layer 3 Interface Connected to a Layer 2 Switchport. Layer 1 goes down and then up. /Subtype /Link >> /Subtype /Link endobj Last clearing of"show interface" counters - The last time the clear counters command was issued since the last time the switch was rebooted. You must enable CDP on all of the Catalyst 4000 family, Catalyst 5000 family, and Catalyst 6500 series switches in the network. For example, if a large amount of traffic bursts comes in on a gigabit interface and is switched out to a 100Mbps interface, this can cause Xmit-Err to increment on the 100Mbps interface. 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 command output displays all network layer (Layer3) devices, such as routers, that the traffic passes through on the way to the destination. 3506 If you have a large number of deferred frames, or Out-Discard (also referred to as Out-Lost on some platforms), it means that the switch output buffers have filled up and the switch had to drop these packets. endobj Cisco ethernet interfaces are normally down / down if they don't have a link. This usually happens because one of the ports of a physically redundant topology (not necessarily the STP block port) no longer receives STP BPDUs. But in full duplex environments the issue occurs when the excessive load is destined for the switch. Every port on a Layer 3 switch configured to be a L2 switchport must also belong to a VLAN. To support authentication for Telnet with secure shell encryption, use the telnet keyword in the set authentication commands. Typically this means frames up to 1600 bytes in size. In addition, these packets are not reported in the appropriate category (unicast, multicast, or broadcast) in receive statistics. In many cases, this is the result of a bad NIC. This example of the show interface command shows theLast input neveron the TenGigabitEthernet1/15 interface. For more information, refer to the UDLD: One-Way link problems section of this document. No destination broadcast are the number of broadcast packets that the port did not forward to any other ports. /P 6 0 R Set the duplex to full-duplex. 15 0 obj Change the software first. When a port receives a Symbol, it extracts the 8 bit data from the Symbol (10 bits). >> 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) To stop a ping in progress, press Ctrl-C. To ping another device on the network from the switch, perform one of these tasks in normal or privileged mode: ping -s host [packet_size] [packet_count]. How to detect port changes in real time on Cisco 4506 Excessive errors for certain counters usually indicate a problem. This happens when new hardware comes out and requires special support from the software. If the ratio of errors to input packets is greater than two or three percent, performance degradation can be noticed. Use these resources to familiarize yourself with the community: Customers Also Viewed These Support Documents. The number of times the carrier was lost in transmission. endobj Make sure each switch can see the end device MAC address in its Content-Addressable Memory (CAM) table. The line protocol up message shows the data link layer status of the interface and says that the interface can send and receive keepalives. This is the command to use on the Catalyst 6000, 4000, 3550, 2950, and and 3750 series. 16 0 obj /Rect [162 456.8999938965 320.8200073242 468.1199951172] 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. For the duplex mismatch scenario, the late collision is seen on the half-duplex side. Small amounts of symbol errors can be ignored. This indicates that a corruption of the packet occurred within transfer, and Blackwater received the corrupted packet. 21 0 obj If not, contact the TAC, as this can be a faulty port. This is not available on all IOS versions. 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 Find answers to your questions by entering keywords or phrases in the Search bar above. This will give you the last upinformation. Destination does not respondIf the host does not respond, a no answer message is returned. 3. Late collisions are not detected by the transmitter until after the first 64 byte slot time. Ensure that you have the correct cable for the type of connection you want to make. For fiber, make sure you have the correct cable for the distances involved and the type of fiber ports that are used. When the VLAN is already in fast aging, EARL cannot set the VLAN to fast aging, and aging timer set process is blocked. >> endobj /Type /Annot Check for loose connections. Check the physical connection on both sides. This situation creates a loop. /Parent 3 0 R Port or Interface Status is Disable or Shutdown Port or Interface Status is errDisable Port or Interface Status is Inactive 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] Trunking Mode Mismatch Jumbos, Giants, and Baby Giants 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. 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. 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. This total includes frames of all destination types. /Border [0 0 0] Make sure that both ends of the cable are plugged into the correct ports. Release Notes for the Cisco Catalyst IR1101 Rugged Series Router There is a difference in the link failure detection times when you run GigabitEthenet on copper versus GigabitEthernet over fiber. If neither auto-negotiation or hardcode setupseem to work, there can be a problem with the firmware or software on your NIC card. Aging Type : Absolute. 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. The operating system can have a bug. If you're seeing up / down, the most likely causes are: Cable fault Speed mismatch (I personally haven't seen a duplex mismatch bring an intf up / down) is cable that connected to the local interface, but not connected to the far end switch, will cause that situation? The size of this buffer is only 16 KB. Port on switch down/down (notconnect) - Cisco - The Spiceworks Community An advantage of PortFast is that this feature suppresses TCNs for a host port. /description () New here? endobj 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. Note: Variables that can affect routing (for example, load and reliability) are not cleared when the counters are cleared. Port status up and down and up again - Cisco Refer toCisco Technical Tips Conventionsfor more information on document conventions. A port remembers what VLAN it is assigned to, even if the VLAN itself is deleted. To use this feature, you must install the application on the client accessing the switch and you must configure SSH the switch. The total number of frames received whose length exceeds the System MTU, yet which have good FCS values. Bad Port or Module Port or Interface or Module not enabled. 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. The increase in the output buffer failure counters can be a sign that the ports are run at an inferior speed and/or duplex, or there is too much traffic that goes through the port. Use theshow cdp neighborscard-type detailcommand to display CDP information for Cisco neighbor devices. 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.
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