Weak current College】 【switch port "robustness" of the processing methods.

<br> <br> The "robustness" phenomenon spread to radical? <br> <br> But in recent days units that connect digital TV front-end system also appeared on the switch ports "robustness" phenomenon, quickly identifying the fault reason .: because the port the following connection of one switch a loop, this CISCO the appropriate ports on the switch will be automatically closed, this measure potential is necessary because you can prevent the spread of the loop, but when the following switch loop failure discharged, .the port does not have to restore to normal working condition, a more terrible is: a, replace the port; second, reset switch cannot be achieved, as a result this switches on the little free ports, the switch must always be working state, .if upon reboot, the few minutes of network outages will affect digital TV broadcast, so is never reset. <br> <br> The emergence of this question, we have to pay attention to a switch port "robustness" that sought in the switch .does not reset the State of the port to "rescue" back essentials. <br> <br> Save the step 1: view log / port status <br> <br> Login into the switch, perform showlog, will see the following prompt .: <br> <br> 21w6d:% ETHCNTR-3-LOOP_BACK_DETECTED: Keepalivepacketloop-backdetectedonFastEthernet0/20. <br> <br> 21w6d:% PM-4-ERR_DISABLE: loopbackerrordetectedonFa0/20, puttingFa0/20inerr-disablestate <br> < .br> The above information clearly expressed since the first 20 port detected a loop, so the port over the err-disable State. <br> <br> View the status of the port <br> <br> Switch # showinterfa0/20status < .br> <br> PortNameStatusVlanDuplexSpeedType <br> <br> Fa0/20linktodatabackuperr-disabled562autoauto10/100BaseTX <br> <br> This article more explicit that the port is in err-disabled state. <br> <br> Since seeing the port is .placed in an incorrect state, we should have it then reverts to normal state. Save the step 2: set the port never correct state restore back <br> <br> To switch the global configuration mode, perform errdisablerecoverycause?, see the following information .: <br> <br> Switch (config) # errdisablerecoverycause? <br> <br> allEnabletimertorecoverfromallcauses <br> <br> bpduguardEnabletimertorecoverfromBPDUGuarderrordisablestate <br> <br> channel-misconfigEnabletimertorecoverfromchannelmisconfigdisablestate <br> <br> dhcp-rate-limitEnabletimertorecoverfromdhcp-rate .-limiterrordisablestate <br> <br> dtp-flapEnabletimertorecoverfromdtp-flaperrordisablestate <br> <br> gbic-invalidEnabletimertorecoverfrominvalidGBICerrordisablestate <br> l2ptguardEnabletimertorecoverfroml2protocol-tunnelerrordisablestate <br> <br> link-flapEnabletimertorecoverfromlink-flaperrordisablestate <br> <br> loopbackEnabletimertorecoverfromloopbackdetecteddisablestate <br> < .br> pagp-flapEnabletimertorecoverfrompagp-flaperrordisablestate <br> <br> psecure-violationEnabletimertorecoverfrompsecureviolationdisablestate <br> <br> security-violationEnabletimertorecoverfrom802.1xviolationdisablestate <br> <br> udldEnabletimertorecoverfromudlderrordisablestate <br> BR> unicast-floodEnabletimertorecoverfromunicastflooddisablestate <br> <br> vmpsEnabletimertorecoverfromvmpsshutdownerrordisablestate < .br>.