does any one have an idea about switch ports going on err-disabled state suddenly
In fact , we have Switch CISCO 3560 POE -48 to each port is connected an IP phone with embedded switch connected to a PC
Sometimes we find the port down , when we enter the sh interface command whe have :
FastEthernet1/0/5 is down, line protocol is down (err-disabled) Hardware is Fast Ethernet, address is 0024.c318.2387 (bia 0024.c318.2387) MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Auto-duplex, Auto-speed, media type is 10/100BaseTX input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 9w4d, output 9w4d, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 16375217 packets input, 3101173312 bytes, 0 no buffer Received 250969 broadcasts (0 multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 226491 multicast, 0 pause input 0 input packets with dribble condition detected 189641431 packets output, 25371607307 bytes, 0 underruns 0 output errors, 24 collisions, 1 interface resets 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 PAUSE output 0 output buffer failures, 0 output buffers swapped out
You can find here the port configuration on the switch
interface FastEthernet1/0/5 switchport access vlan 1700 switchport mode access switchport voice vlan 1500 spanning-tree portfast spanning-tree bpduguard enable
show interface Fa 1/0/5 status err-disabled
will give you the reason for why the port was errdisabled.