Collisions must not be seen on interfaces configured as full duplex. 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. 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. /MediaBox [0 0 612 792] Cisco IOS error counter output forshow interfacesorshow interfaces counters errorsfor the Catalyst 6000 and 4000 Series. The messages are generated by the switch. When you operate at full-duplex, errors in FCS, Cyclic Redundancy Checks (CRC), alignment, and runt counters must be minimal. l2trace {src-ip-addr} {dest-ip-addr} [detail]. >> /Count 14 You can display the currently active user sessions on the switch using the show users command. If the mismatch occurs between two Cisco devices with the Cisco Discovery Protocol (CDP) enabled, you see the CDP error messages on the console or in the logging buffer of both devices. Usually this means there was no packet transfer relative to that entity. endobj For this reason, they were discarded by the switch. Common Causes:Excessive collisions are typically an indication that the load on the segment needs to be split across multiple segments but can also point to a duplex mismatch with the attached device. 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. Port status as seen in the color assist mode. The total number of frames whose first transmission attempt was delayed, due to traffic on the network media. As the half-duplex side transmits, the full duplex side does not wait its turn and transmits simultaneously which causes a late collision. /Producer (Acrobat Distiller 7.0 \(Windows\)) Just issue the 'show interface fx' command and look under 'Last input/Last output. Therefore, this sum cannot balance with the sum of enumerated input error counts. A link light does not guarantee that the cable is fully functional. If the segment is shared, other devices on this segment can transmit so much that the switch has no opportunity to transmit. The documentation set for this product strives to use bias-free language. /Resources 30 0 R Follow the below . Changes aresavedto the config in Cisco IOS with the write memory command. Monitorthese counters for increments as it is useful to determine whether traffic flows properly through the interface. On the 2900/3500XL, 2950/2955, 3550, 2970 and 3750 series switches the equivalent command is show post which displays the results of the switch POST. But in full duplex environments the issue occurs when the excessive load is destined for the switch. /Rect [162 320.8800048828 286.5599975586 332.1600036621] %PDF-1.4 Look at your logs (if link state logging is enabled) for signs of the interface going down/up. << For a 10 Mbit/s port this is later than 512 bit-times into the transmission of a packet. InCisco IOS software you have the ability to automatically re-enable a port after a configurable amount of time spent in the errdisable state. 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 maximum number of hops an l2trace query will try is 10; this includes hops involved in source tracing. 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. The second router sees a TTL value of 1, discards the datagram, and returns the time-exceeded message to the source. /Metadata 4 0 R 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. (Line down/up), Layer 2 goes down and then up. << Description:show interfacesandshow interfaces counters errors. For more information on software compatibility, use the Software Advisor tool. The alternative is to contact the vendor for software/hardware upgrade for IEEE 802.3z Gigabit auto-negotiation support. /contentType () << 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. You can need to modify your network topology to reduce the traffic load for this switch. The source and destination switches must belong to the same VLAN. 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 << Destination unreachableIf the default gateway cannot reach the specified network, a destination unreachable message is returned. Use theshow interfaces statuscommand to display speed and duplex setup as well as other information. ctsadmin-p.gen See "Working with System Software Images," for the software image naming conventions that are used for the encryption images. Up to eight simultaneous Telnet sessions are possible. Make congestion avoidance a priority on your network. Swap the GBIC (if removable) for fiber connections. The issue occurs when an excessive amount of traffic is processed by the Fast Ethernet interface. % /Rect [162 337.9200134277 311.1000061035 349.1400146484] The number of times multiple collisions occurred before the interface transmitted a frame to the media successfully. 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. It is caused by protocols that are not understood by the router/switch. In Cisco IOS, you can use theswitchport hostcommand to disable channeling and to enable spanning-tree portfast and theswitchport nonegotiatecommand to turn off DTP negotiation packets. Change the cable and patch panel cord to ensure that the cable and patch cords are not defective. . 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. Most Cisco switches have a port in the notconnect state. Multiple splices and substandard fiber-optic cable reduce the cable distances. Bad or wrong Gigabit Interface Convertor (GBIC). This is an example of output from the show interfaces command for an interface: "How long the port is in Up or Down status" is NOT the same thing as "the last time a port sent or received traffic." Giant frames are defined as any frame over the maximum size of an ethernet frame (larger than 1518 bytes) that has a bad FCS. These are the total number of packets received that were less than 64 octets long (which excludes frame bits but includes FCS) and have a good FCS value. Check the physical connection on both sides. An advantage of PortFast is that this feature suppresses TCNs for a host port. /Type /Annot All switches in the path must be reachable from each other. switch# show vtp status VTP Version : 1 Configuration Revision : 0 . 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. The Pluggable Module provides the flexibility of adding different interfaces to the IR1101 platform, for example, a cellular module. Refer toInterface/Module Connectivity Problemsfor more information on oversubscription. 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 . A switch is in down state when there is nothing connected to the port or if its admin shutdown. 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. /Rotate 0 The port can be configured to filter 802.1Q tagged frames. >> The MFD is a function of the core diameter, the wavelength of the laser, and the refractive index difference between the core and the cladding. If an egress interface is over-subscribed, it is normal to see output buffer failures that increment along with Out-Discards. 1 0 obj The command udld aggressive-mode can be configured on switches that run Cisco IOS (check release notes for command availability) for point-to-point connections between switches where unidirectional links cannot be tolerated. 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]. A unidirectional link is a link where traffic goes out one way, but no traffic is received in the ingress direction. 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). You can move the device that hangs off this port to faster media. endobj Always ground the cables (especially in new cable runs) to a suitable and safe earth ground before you connect them to the module. This error message is caused when a frame is transmitted, and the local buffer of the controller chip local buffer receives insufficient data. /Title (Checking Port Status and Connectivity) To enable err-disabled ports on Cisco 3750 switch series. This only happens under stress conditions but can happen with bursts of traffic on several ports. The Catalyst4912G, 2948G, and 2980G switches are fixed-configuration switches but are logically modular. Description:show interfacesand show interfaces counters errors. /Border [0 0 0] 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. This usually happens because one of the ports of a physically redundant topology (not necessarily the STP block port) no longer receives STP BPDUs. /keywords () (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? Without the loop guard feature, the port assumes the designated port role. If the switch overwhelms the Ethernet interface, check the speed and duplex setup. If the VLANs are frequently in fast aging, check the reason for fast aging. The mode-conditioning patch cord is required for link distances less than 328 feet (100 m) or greater than 984 feet (300 m). Specify a particular module number to see information on the ports on that module only. Cisco Internetwork Operating System Software . The operating system can have a bug. 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. Therefore, it applies to only process switched traffic. UDLD can put a port in errdisable state when it detects a unidirectional link. stream The traceroute facility determines the address of the first hop by examining the source address field of the ICMP time-exceeded message. >> Without attenuators, the minimum link distance is 24.9 miles (40 km). /Dest (G1040467) endobj The only way to clear the bit counters in these switches is to reload. The traffic load destined for this switch is excessive and causes the frames to be discarded. /Creator (FrameMaker 7.2) Reduce the switch load if thenumber of packets in this field increase. If you do not include a specific interface, it will show all the interfaces. The line protocol up message shows the data link layer status of the interface and says that the interface can send and receive keepalives. The remote device is expected to stop / reduce the transmission of packets for the interval time mentioned in the pause frame. The IEEE ethernet specification forbids this bit to be set in any Ethernet frame. /secondaryConcept () This means that if the 2 collision frames counter incremented, the switch attempted to send the packet twice and failed but was successful on its third attempt. The traffic load on the interface is excessive and causes the frames to be discarded. In order to overcome this situation, manually configure the speed and duplex, as well as disable the flow control, if required. (The flushes counter can be used but never increments on the Catalyst 4000 Series that run Cisco IOS.) Maximum MAC Addresses : 1. Reduce the traffic load on the interface if there are incrementsin the number of packets in this field. /P 6 0 R Wheb ports or interlaces are shut down as a result of errdisable are referred to as causes in Cisco IOS. This can be an indication of faulty hardware, dot1q or ISL trunking configuration issues. Every port in a Layer 2 switch belongs to a VLAN. The Maximum Transmission Unit (MTU) of the data portion of an ethernet frame is 1500 bytes by default. 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. It takes 300msec for the card firmware to notify the software that a 10/100/1000BASE-TX link/port is down. Is there a command that will show information as to how long that port has been in an "up" state? If a port just acquired a link, there is a very brief (less than one second) period where inbound packets are not forwarded. The number of times the carrier was lost in transmission. These random drops are called SPD flushes. The total number of frames received whose length exceeds the System MTU, yet which have good FCS values. 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. Change the software first. Thanks for this! 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. << For general configuration information and additional information on how to troubleshoot, refer to Configuring and Troubleshooting Ethernet 10/100/1000 MB Half/Full Duplex Auto-Negotiation . 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 /description () 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. This is an indication of a bad frame generated by the connected device. 0 Helpful Share Reply johnlloyd_13 Engager Options 09-27-2014 02:01 AM Hi, Description:show interfacescounter. /Border [0 0 0] Try to find the offending device and remove it from the network. 2011-03-17T11:53:32Z Support for jumbo and baby giants on Catalyst switches varies by switch platform, sometimes even by modules within the switch. Sometimes a cable appears to be seated in the jack but is not. 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. /accessLevel (Guest,Customer,Partner) When a frame is received which contains an 802.1Q tag the frame is filtered and this statistic is incremented. 5 minute input/output rate - The average input and output rate seen by the interface in the last five minutes. If you have device A connected to device B over a Gigabit link, and the link does not come up, perform this procedure. 03-01-2019 For troubleshoot information, see theDeferred Frames (Out-Lost or Out-Discard)section of this document. 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. Once you have encapsulation dot1q on a subinterface, you can no longer use that VLAN in the system because the 6500 or 7600 internally allocates the VLAN and makes that sub interface its only member. /I 31 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. /Length 13 0 R Description:show interfacescounter. Always set both sides of the connection to auto-negotiate speed/duplex or set the speed/duplex manually on both sides. For fiber, make sure you have the correct cable for the distances involved and the type of fiber ports that are used. Make sure that both ends of the cable are plugged into the correct ports. The error message is received when the traffic level reaches about 2.5 Mb.

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