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1. SMART TIMER COLLISION MODE HOW TO
2. SMART TIMER COLLISION MODE DRIVER
3. SMART TIMER COLLISION MODE SOFTWARE
4. SMART TIMER COLLISION MODE SERIES

In order to disable error-disable detection, use the no errdisable detect cause command. Note: Error-disable detection is enabled for all of these reasons by default. Incorrect GBIC / Small Form-Factor Pluggable (SFP) module or cableĪddress Resolution Protocol (ARP) inspection UniDirectional Link Detection (UDLD) condition There are various reasons for the interface to go into errdisable. Because of the carrier sense multiple access (CSMA) nature of Ethernet, collisions are normal for half duplex, as long as the collisions do not exceed a small percentage of traffic. Only half-duplex connections can ever have collisions in a LAN.

SMART TIMER COLLISION MODE DRIVER

Possible causes of these types of errors include:Ī cable that is out of specification (either too long, the wrong type, or defective)Ī bad network interface card (NIC) card (with physical problems or driver problems)Ī port duplex misconfiguration is a common cause of the errors because of failures to negotiate the speed and duplex properly between two directly connected devices (for example, a NIC that connects to a switch). Late collisions occur because every device on the wire did not recognize that the wire was in use. Excessive collisions occur when a frame is dropped because the switch encounters 16 collisions in a row. This feature was first implemented in order to handle special collision situations in which the switch detected excessive or late collisions on a port. The error disable feature helps prevent these situations. Such a failure can occur when a bad port monopolizes buffers or port error messages monopolize interprocess communications on the card, which can ultimately cause serious network issues.

It eliminates the possibility that this port can cause other ports on the module (or the entire module) to fail. It lets the administrator know when and where there is a port problem. The error disable function serves two purposes: The actual message depends on the reason for the error condition. This example message displays when a host port receives the bridge protocol data unit (BPDU). Disabling port.īpduguard error detected on Gi4/1, putting Gi4/1 in err-disable state Received BPDU on port GigabitEthernet4/1 with BPDU Guard enabled. Or, if the interface has been disabled because of an error condition, you can see messages that are similar to these in both the console and the syslog: %SPANTREE-SP-2-BLOCK_BPDUGUARD: Here is an example of what an error-disabled port looks like from the command-line interface (CLI) of the switch: cat6knative#show interfaces gigabitethernet 4/1 status The port LED is set to the color orange and, when you issue the show interfaces command, the port status shows err-disabled. When a port is error disabled, it is effectively shut down and no traffic is sent or received on that port.

SMART TIMER COLLISION MODE SOFTWARE

In other words, the port is automatically disabled by the switch operating system software because of an error condition that is encountered on the port. If the configuration shows a port to be enabled, but software on the switch detects an error situation on the port, the software shuts down that port. This document specifically focuses on errdisable for switches that run Cisco IOS Software. The way in which errdisable is implemented varies between software platforms. The errdisable feature is supported on these Catalyst switches:Ĭatalyst switches that run Cisco IOS Software:Ĥ500 / 4503 / 4506 / 4507 / 4510 / 4500-X Background Information Platforms That Use Errdisable If your network is live, ensure that you understand the potential impact of any command. All of the devices used in this document started with a cleared (default) configuration. The information in this document was created from the devices in a specific lab environment. The switches must run Cisco IOS ® Software and each switch must have two Fast Ethernet ports that are capable of EtherChannel and PortFast.

SMART TIMER COLLISION MODE SERIES

To create the examples in this document, you need two Cisco Catalyst 4500/6500 Series Switches (or the equivalent) in a lab environment with cleared configurations. There are no specific requirements for this document. Note: The port status of err-disabled displays in the output of the show interfaces interface_number status command. These customers want to know why the error disablement happened and how they can restore the ports to normal. Customers often contact Cisco Technical Support when they notice that one or more of their switch ports have become error disabled, which means that the ports have a status of errdisabled. This document uses the terms errdisable and error disable interchangeably.

SMART TIMER COLLISION MODE HOW TO

This document describes the errdisabled state, how to recover from it, and provides examples of errdisable recovery.