Cisco Catalyst IR1101 Rugged Series Router. 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. /Rotate 0 Monitorthese counters for increments as it is useful to determine whether traffic flows properly through the interface. To display summary information on all of the ports on the switch, enter the show port command with no arguments. 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. The messages are generated by the switch. 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. << Verify device A and B use the same GBIC, short wavelength (SX), long wavelength (LX), long haul (LH), extended wavelength (ZX), or copper UTP (TX). Acrobat Distiller 7.0 (Windows) You must apply configuration commands to the appropriate module. By default, software processes inside the switch can shut down a port or interface if certain errors are detected. The port can be configured to filter 802.1Q tagged frames. You can trace a Layer 2 path by specifying the source and destination IP addresses (or IP aliases) or the MAC addresses. Issue theshow cam agingcommand to check the CAM aging time on the switch. /Dest (G1060208) Unplug the cable and reinsert it. As the half-duplex side transmits, the full duplex side does not wait its turn and transmits simultaneously which causes a late collision. An increment in pause input counter means that the connected device requests for a traffic pause when its receive buffer is almost full.Common Causes:This counter is incremented for informational purposes since the switch accepts the frame. 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 . Port Name Status Vlan Duplex Speed Type . Description:show interfaces counters errors. To determine when a datagram reaches its destination, traceroute sets the UDP destination port in the datagram to a very large value that the destination host is unlikely to be using. 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. /Border [0 0 0] 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. Check the results ofshow modulefor Catalyst 6000 and 4000 series switches that run Cisco IOS. /P 6 0 R Trunk links between a switch and a router can make the switchport go down. 7 0 obj It is this configuration that is loaded into memory when the device is first booted. ), how to connect the different cables, and which cables are used by most Cisco switches and modules, refer to Catalyst Switch Cable Guide . /Length 13 0 R Last input nevermeans there was no successful interface packet transfer to other end point or terminal. /EmbeddedFiles 11 0 R When a frame is received which contains an 802.1Q tag the frame is filtered and this statistic is incremented. This kind of source routing is only defined for Token Ring and FDDI. 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. Run a port TDR to test the integrity of the copper cable. This means it is currently not connected to anything, but it can connect if it has a good connection to another operational device. 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. /ModDate (D:20110317115332Z) In switches that support both L3 interfaces and L2 switchport, the message"Command rejected: [interface] not a switching port"displays when you try to enter a command related to layer 2 on a port that is configured as a layer 3 interface. 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. An excessively loaded network can be caused by too many devices on a shared Ethernet. In order to resolve this issue, create trunk ports instead of sub interfaces. /Subtype /Link If this counter increments, this is an indication that the ports are configured at half-duplex. All switches in the path must be reachable from each other. Most switches have some way to track the packets and errors that occur on a port or interface. - last edited on Note: There is, an Out-Discard counter in the Cisco IOSshow interfaces counters errorscommand which is explained inTable 1. endobj This example of theshow run interfacecommand shows the unknown protocol drops on the GigabitEthernet 0/1 interface. /Type /Catalog << /Contents 29 0 R Reduce the traffic load on the interface if you see the number of packets increase in these fields. /language (en) The excessive collisions counter increases after 16 consecutive late collisions have occurred in a row. Spanning Tree Protocol (STP) loops can cause serious performance issues that masquerade as port or interface problems. The Catalyst4912G, 2948G, and 2980G switches are fixed-configuration switches but are logically modular. (It still must be far less than one percent of the frames received.). When the cable is first connected to the port, some of these errors can occur. 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. Always ground the cables (especially in new cable runs) to a suitable and safe earth ground before you connect them to the module. /Rect [162 320.8800048828 286.5599975586 332.1600036621] Large amounts of symbol errors can indicate a bad device, cable, or hardware. This area consists of the fiber core plus a small portion that covers the cladding. 27 0 obj If the FCS, CRC, alignment, or runt counters increment, check for a duplex mismatch. /Count 14 Description:sh interfacescounter. When you power up or down the PC, the switch port changes state, and the switch starts the TCN process. This is useful to know when a dead interface failed. When you add the VLAN back into the VLAN table from a VTP server switch, the ports of the switches in the domain that belong to that restored VLAN become active again. A port remembers what VLAN it is assigned to, even if the VLAN itself is deleted. Problems sometimes occur between Cisco switches and certain third-party NIC cards. << Description:show interfacesandshow interfaces counters errors. This will give you the last upinformation. >> >> Refer to theCatalyst Switch Cable Guide. Look at your logs (if link state logging is enabled) for signs of the interface going down/up. >> << /I 31 0 R Hardware is AmdFE, address is 000e.8485.8820 (bia 000e.8485.8820) . The interaface also shows a UP/UP state. The collision frames counters are the number of times a packet was attempted to be transmitted but was not successful but was successful on its next attempt. >> Reduce the traffic load on the interface if there are incrementsin the number of packets in this field. This commanda display the 32-bit and 64-bit error counters per port or interface. << 13 0 obj 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. It is usually easier to upgrade the software than it is to upgrade hardware. PDF Checking Port Status and Connectivity - cisco.com /Border [0 0 0] Try the following commands. 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? 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. endobj On one of my 3750's ports that have never gone down show a 1993 timestamp, ports that have gone up/down have a recent (correct) date, 1 link ups, last link up on Sun Feb 28 1993, 16:01:20, 4 link ups, last link up on Tue Dec 02 2014, 14:51:11. It is common for devices like laptops or other devices to be set to autonegotiate as well, yet sometimes autonegotation issues occur. /Subtype /Link When a host receives a datagram with an unrecognized port number, it sends an ICMP port unreachable error to the source. It has helped us a lot. If you do not include a specific interface, it will show all the interfaces. Bypass the patch panel if possible to rule it out. 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 port starts to drop the packets when the Tx buffer is full and thus increases the underruns and the output buffer failure counters. This is only required if end-devices such as older Gigabit NICs are used which cannot support IEEE 802.3z. SecureStatic Address Aging : Disabled. /Count 4 1 0 obj When you operate at full-duplex, errors in FCS, Cyclic Redundancy Checks (CRC), alignment, and runt counters must be minimal. >> 06-22-2009 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. Check or swap the copper or fiber cable. Impossible to tell. 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. 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. 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 This difference in detection time is based on the IEEE standards. For fiber, make sure you have the correct cable for the distances involved and the type of fiber ports that are used. For example, you have a switch that has two Gigabit ports. 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. 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. >> Cisco: All about errdisable (and how to enable ports disabled by it) 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). In order to check to see how long the port is in Up or Down status, use the show interfaces [interface id] command. ), 2900/3500XL only.The number of times that a port received a packet from the network, but the switch did not have the resources to receive it. The number of frames dropped on an interface because the CFI bit is set. "Port Status" in the output of "show port-security" - Cisco 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. 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. Note: Refer toUsing Portfast and Other Commands to Fix Workstation Startup Connectivity Delaysfor more information how to fix startup delays. 20 0 obj Description:show interfaces counters errors. 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. This is helpful to use to determine whether a misconfiguration of the mod/port or interface can cause a problem. Gigabit Ethernet (1000 Base-X) uses 8B/10B Encoding to translate 8bit data from the MAC sublayer(layer 2) to a 10bit Symbol to send over the wire. This is usually seen in half-duplex environments where the carrier is already in use when it tries to transmit a frame. Note: There can be differences in the implementation of the counters across various platforms and releases. >> /N 28 0 R >> 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). (Protocol down/up). In order to overcome this situation, manually configure the speed and duplex, as well as disable the flow control, if required. To display the active user sessions on the switch, perform this task in privileged mode: Display the currently active user sessions on the switch. Resolution In order to check to see how long the port is in Up or Down status, use the show interfaces [interface id] command. Change the cable and patch panel cord to ensure that the cable and patch cords are not defective. Connections for transmit-to-transmit and receive-to-receive do not work. The table describes the LED status indicators for Ethernet modules or fixed-configuration switches: Ensure that both sides have a link. Look at the "sh interface <BLAH>" and "sh controll e <BLAH>" any any line errors. The number of received packets ignored by the interface because the interface hardware ran low on internal buffers. Trace a Layer 2 path using IPaddresses or IP aliases. Use theshow cdp neighborscard-type detailcommand to display CDP information for Cisco neighbor devices. stream The numbers given for multimode fiber-optic cable refer to the core diameter. Port status : Secure down help TechExams Community Does the link come up? 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. Table 1. Note: For 2900/3500XL Series switches use theshow interfacescard-type {slot/port}command with theshow controllers Ethernet-controllercommand. Collisions in a half-duplex environment are normal expected behavior. /CropBox [0 0 612 792] Set the duplex to full-duplex. The Catalyst 6000/4000 does not turn the port light orange when it blocks for STP. Upgrade the NIC card driver to the latest version available on the web site of the manufacture to resolve this. You can need to modify your network topology to reduce the traffic load for this switch. Note: PortFast also bypasses spanning-tree calculations on the port, and is therefore only suitable for use on a host port. Alignment errors are due to the frame that is not completely copied to the wire, which results in fragmented frames. Violation Mode : Shutdown. Therefore, it applies to only process switched traffic. 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. /Count 24 For Cisco IOS, use theshow interfacescard-type {mod/port}trunkcommand to verify the trunking configuration and Native VLAN. This can lead to slow throughput of packets across the device. The loop guard feature makes additional checks. To enable err-disabled ports on Cisco 3750 switch series. The most common reason for TCNs is client PCs connected directly to a switch. You have to manually re-enable the port or interface to take it out the errdisable state unless you configure an errdisable recovery option. /Parent 5 0 R This command displays output similar to a Cisco router, like software image name and version information and system memory sizes. After 16 attempts have been made to send the packet the packet is dropped, and the counter increments. If a packet is sent from any other port, in the same VLAN as port 0/2, the packet is dropped. 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. 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. 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, refer to the UDLD: One-Way link problems section of this document. << Basically, up/down means the port is available for a cable/connection, but doesn't have one. This chapter describes how to check switch port status and connectivity on the Catalyst enterprise LAN switches. If the CFI bit is set to 1, this indicates the presence of a RIF (Routing Information Field) or Token Ring noncanonical frame which is discarded. 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. 26 0 R] If the ratio of errors to input packets is greater than two or three percent, performance degradation can be noticed. 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. Destination does not respondIf the host does not respond, a no answer message is returned. >> >> I have a port that I believe is going up and down on a 2960X-port switch. If the switch overwhelms the Ethernet interface, check the speed and duplex setup. /Rect [162 388.9200134277 312.299987793 400.1400146484] You must either enable or disable link negotiation on both ends of the link. Thus, Rx-No-Pkt-Buff on each port can be counted when the total traffic rate of this ASIC port group exceeds 1 Gbps, since WS-X4548-GB-RJ45 is 8:1 oversubscribed module. The purpose of SPD is to ensure that important control packets, such as routing updates and keepalives, are not dropped when the IP input queue is full. MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, Last clearing of "show interface" counters never, Customers Also Viewed These Support Documents, How to find the port Uptime/Downtime status or utilization in Catalyst 3750 series switches that run Cisco IOS system software. 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. Try the cable in another port or interface if one is available and see if the problem continues. 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. But the problem is that this OID returns "1:up" as soon as a cable is plugged into the port and does not reflect the different status the port might have including: Blinking green: Link has activity Solid amber: Port is faulty etc, Any clue or hint on which OIDs I should use? Use theclear counterscommand to zero the traffic and error counters so that you can see if the problem is only temporary, or if the counters continue to increment. Port Status : Secure-down. This chapter includes the following major sections: Checking Module Status, page 5-1 Checking Interfaces Status, page 5-2 Checking MAC Addresses, page 5-3 Trunking changes the formatting of the packet. /MediaBox [0 0 612 792] Alignment errors are the number of frames received that do not end with an even number of octets and have a bad CRC. endobj Is there a command that will show information as to how long that port has been in an "up" state? The results of a duplex mismatch are extremely slow performance, intermittent connectivity, and loss of connection. %LINK-3-UPDOWN messages in the log show when the port status. After 12.1(19)EW, a giant inshow interfacesincrements only when a frame is received >1518bytes with a bad FCS. << Table20-1 lists the default values that apply to the ping-s command. WK:w9\lBdOeX>V!RKB.GUMrx8<3pfs,nNX`IVw=OYGe; L2]>[1aUGYv4(}d({PJRiPh@fHK49]a9l&]+X.H bVFO4 i8qQf3 These delays are caused by STP, trunking negotiations (DTP), and EtherChannel negotiations (PAgP). 2900/3500XL only.The number of times that a port received a packet from the network, but the switch did not have the resources to receive it. Cisco IOS has the option to use theglobal spanning-tree portfast defaultcommand to automatically apply portfast to any interface configured as a layer 2 access switchport. Always check the cable for marginal damage or failure. endobj When a device is connected to a switchport ..%LINK-3-UPDOWN messages in the log show when the port status. This is the command to use on the Catalyst 6000, 4000, 3550, 2950, and and 3750 series. UDLD can put a port in errdisable state when it detects a unidirectional link. /Author (ctsadmin-p.gen) You could try and set the keepalive timer on your switchports to something higher than the highest interval seen in your logs, say 20 minutes. Also you can use (it is disruptive for the port): test cable-diagnostics tdr interface xx/yy and then The 300msec default debounce timer comes from the firmware polling timer to the linecards, which occurs every 300 msec. Use theshow versioncommand to verify the current software version along with thedir flash: ordir bootflash: (dependent upon the platform) command to verify the available flash memory for the upgrade: For information on how to upgradesoftware for your Cisco Switches, navigate to link, choose your platform and look at the Software Configuration section. /Last 44 0 R How to find the port Uptime/Downtime status or utilization in - Cisco Verify the cable selection. What can cause "FastEthernet is up, line protocol is down" on a Cisco Theshow modulecommand can indicate faulty, which can indicate a hardware problem. /Rect [162 337.9200134277 311.1000061035 349.1400146484] Five hundred and twelve bit-times corresponds to 51.2 microseconds on a 10 Mbit/s system. Make sure both sides are in the same mode (both trunking with the same method: ISL or 802.1q, or both not trunking).
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