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. 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? 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. endobj Check the port status on both sides. An excessive collision happens when a packet has a collision 16 times in a row. endobj Refer toInterface/Module Connectivity Problemsfor more information on oversubscription. This is not available on all IOS versions. Status is whether or not the interface is enabled administratively or if there is a physical connection to another device on the other end. i see. Description:show interfacescounter. 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. A key size with a larger number provides higher security but takes longer to generate. Alignment errors are a count of the number of frames received that do not end with an even number of octets and have a bad Cyclic Redundancy Check (CRC).Common Causes:These are usually the result of a duplex mismatch or a physical problem (such as cabling, a bad port, or a bad NIC). Typically, the output drops can occur if QoS is configured and does not provideenough bandwidth to certain class of packets. /date (2007-05-04T15:24:40.000-07:00) /Dest (G1019941) Theshow interfacescard-type {slot/port}counterscommand is used when you run Cisco IOS on the Supervisor. Description:show interfacescounter. Description:show interfacesandshow interfaces counters errors. /Type /Page This example shows the basic usage of the traceroute command: This example shows how to perform a traceroute with six queries to each hop with packets of 1400bytes each: Catalyst 4500 Series Software Configuration Guide, 7.5, Configuring the Switch IP Address and Default Gateway, Configuring Ethernet and Fast Ethernet Switching, Configuring Fast EtherChannel and Gigabit EtherChannel, Configuring Spanning Tree PortFast, BPDU Guard, BPDU Filter, UplinkFast, BackboneFast, and Loop Guard, Configuring VLAN Trunks on Fast Ethernet and Gigabit Ethernet Ports, Configuring Dynamic VLAN Membership with VMPS, Catalyst 4500 Series, Catalyst 2948G and Catalyst 2980G Switches Software Configuration Guide, 7.5, "Configuring the Switch IP Address and Default Gateway. R2#show inter fa 0/0. Use theshow interfacecommand for Cisco IOS to look for errdisable, disable or shutdown status. Sometimes a cable appears to be seated in the jack but is not. /Border [0 0 0] endobj When you operate at half-duplex setup, some data link errors incrementin Frame Check Sequence (FCS), alignment, runts, and collision counters are normal. /Count 14 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). 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. This is an indication that the internal send (Tx) buffer is full.Common Causes:A common cause of Xmit-Err can be 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. A port remembers what VLAN it is assigned to, even if the VLAN itself is deleted. Description:show interfaces counters errors. 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. In order to resolve this, change the mode of the switch port tostatic accessortrunkas per your requirement. Some workstations simply cannot wait this long to find their server and then they give up. i feel this command is only for trunks using DTP and not for access ports. The sum of all errors that prevented the final transmission of datagrams out of the interface.Common Cause:This issue is due to the low Output Queue size. An SX GBIC needs to connect with an SX GBIC. 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. It is common for devices like laptops or other devices to be set to autonegotiate as well, yet sometimes autonegotation issues occur. Full-duplex, 100Mb/s - Full-duplex and 100Mbps is the current speed and duplex setup of the interface. This example shows the source and destination MAC addresses specified, with no VLAN specified but with the detail option specified. Is there a command that will show information as to how long that port has been in an "up" state? Collisions must not be seen on interfaces configured as full duplex. In its operation, STP relies on continuous reception or transmission of BPDUs based on the port role. Destination unreachableIf the default gateway cannot reach the specified network, a destination unreachable message is returned. 9 0 obj 21 0 obj Does the port come up? New here? 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. Late collisions can also indicate an Ethernet cable or segment that is too long. This example shows you how to display the MAC address of a specific port: This example shows you how to display the MAC addresses of all ports on a module: You can display the capabilities of any port in a switch using the show port capabilities command. An alternative to this command (for Catalyst 6000, 4000, 3550, 2970 2950/2955, and 3750 series switches) is theshow interfacescard-type
counters errorscommand which only displays the interface error counters. 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. You can use the [mod_num] argument to specify a particular module number to see detailed information on that module. The ping command is configurable from normal executive and privileged executive mode. If you do not include a specific interface, it will show all the interfaces. /Dest (G1060208) You can use IP traceroute to identify the path that packets take through the network on a hop-by-hop basis. This only happens under stress conditions but can happen with bursts of traffic on several ports. It is counted with short traffic bursts flow when some packets fill this buffer. The SSH feature provides security for Telnet sessions to the switch. The operating system can have a bug. This is useful to know when a dead interface failed. Share Improve this question Follow asked Aug 23, 2015 at 6:13 ae41 Duplex mismatch is a situation where the switch operates at full-duplex and the connected device operates at half-duplex, or vice versa. Platform Exceptions:Catalyst Cat4000 Series that run Cisco IOSPrevious to software Version 12.1(19)EW, the giants counter incremented for a frame > 1518bytes. 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. This only happens under stress conditions but can happen with bursts of traffic on several ports. Each time we previously disconnected and reconnected the cable the port status just remained down/down. /Parent 5 0 R The same output show up for trunk ports as well as access ports. Eliminate faulty media convertors: fiber-to-copper, and so on. Jumbo frames are not defined as part of the IEEE Ethernet standard and are vendor-dependent. /Dests 10 0 R To apply configuration commands to a particular port, you must specify the appropriate logical module. ', 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. This can be caused by a duplex mismatch and physical problems, such as a bad cable, port, or NIC on the attached device. Use theshow cdp neighborscard-type detailcommand to display CDP information for Cisco neighbor devices. This only happens under extreme, high stress conditions. Look for broken or lost pins on connectors. You must apply configuration commands to the appropriate module. The number of received packets discarded because there is no buffer space.Common Causes:Compare with ignored count. Description:show interfacesand show interfaces counters errors. endobj /Creator (FrameMaker 7.2) If the FCS, CRC, alignment, or runt counters increment, check for a duplex mismatch. Description:sh interfacescounter. Every port on a Layer 3 switch configured to be a L2 switchport must also belong to a VLAN. >> The first up refers to the physical layer status of the interface. >> Broadcast storms can often be responsible for these events. 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 traceroute command uses the Time To Live (TTL) field in the IP header to cause routers and servers to generate specific return messages. /Rect [162 439.9200134277 349.799987793 451.1400146484] 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. << A fragment is a frame < 64 bytes but with a bad CRC. traceroute [-n] [-w wait_time] [-i initial_ttl] [-m max_ttl] [-p dest_port] [-q nqueries] [-t tos] host [data_size]. endobj 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. In this situation, your bandwidth is used by the same frames over and over again, which leaves little room for legitimate traffic. ^ %-V5V'}ho0&qctqW
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mwPoOfT30Q-oI+M9md%EQebo'07rMgFd51/`(cj -Bf4 }qwaSX K((EFv=rvR_9xD x6OpX2W&r?zu=T >> Always use either Category 5, Category 5e, or Category 6 UTP for 10/100 or 10/100/1000Mbps connections. Resolution In order to check to see how long the port is in Up or Down status, use the show interfaces [interface id] command. The number of times the receiver hardware was unable to hand received data to a hardware buffer. Description:show interfacescounter. I have a port that I believe is going up and down on a 2960X-port switch. >> It depends on the amount of the packets that are stored in the Rx FIFO buffer of the module ASIC. There are two status elements to detect a link being usable or not: Status and Line Protocol. A cable can be just good enough to connect at the physical layer, but it corrupts packets as a result of subtle damage to the wiring or connectors. There are no specific requirements for this document. This means that the port is up as far as Layer 1 (L1) is concerned. Verify that each device supports 802.3z specification for Gigabit auto-negotiation. 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 a device is connected to a switchport ..%LINK-3-UPDOWN messages in the log show when the port status. Check or swap the copper or fiber cable. The rcv-err counter on a 5K only increments as a result of excessive traffic. Hardware is AmdFE, address is 000e.8485.8820 (bia 000e.8485.8820) . Disable theKeepaliveson the interface of the router. In half-duplex environments, it is possible for both the switch and the connected device to sense the wire and transmit at exactly the same time and result in a collision. You can move the device that hangs off this port to faster media. /iaPath () Verify Hw and Sw support for this type of GBIC. Refer to theCatalyst Switch Cable Guide. The two options are single mode fiber (SMF) or multimode fiber (MMF). Without attenuators, the minimum link distance is 24.9 miles (40 km). The show interface command displays the administrative and operational status of a switchport, input and output packets, buffer failures, errors, and so on. When you power up or down the PC, the switch port changes state, and the switch starts the TCN process. /Metadata 4 0 R This shows the last time a port sent or received traffic. /Subtype /Link Swap suspect GBIC with known good GBIC. Using Secure Shell Encryption for Telnet Sessions. This ensures that the MAC address table (the CAM table) contains the most recent entries. Bad or wrong Gigabit Interface Convertor (GBIC). 13 0 obj /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 When a port is in error-disabled state, it is effectively shut down and no traffic is sent or received on that port. Check the IP address, subnet mask, default gateway, dynamic routing protocol configuration, static routes, and so on. 26 0 R] The documentation set for this product strives to use bias-free language. This is the command to use on the Catalyst 6000, 4000, 3550, 2950, and 3750 series. Congestion can lead to packet loss. endobj Most switches have some way to track the packets and errors that occur on a port or interface. Number of frames that took longer than two seconds to travel through the switch. << Description:show interfaces counters errors. In order to resolve this issue, complete these steps: Make sure Cisco Discovery Protocol (CDP) runs between the switch and router and both can see each other. When a device is connected to a switchport .. %LINK-3-UPDOWN messages in the log show when the port status. 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. Port Overview The Switch Ports section shows a basic view of the status of all switch ports. >> The error message is received when the traffic level reaches about 2.5 Mb. 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. The resolution is that ordinarily the system recovers automatically. If this counter increments, it is an indication of a wiring problem, an excessively loaded network, or a duplex mismatch. This can occur when you manually hardcodethe speed and duplex or from auto-negotiation issues between the two devices. 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. Alignment errors are due to the frame that is not completely copied to the wire, which results in fragmented frames. Warning: Disable auto-negotiation and this hides link drops or physical layer problems.