Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Interface Trouble?


I have a 2950 switch. 24 port. IOS is c2950-i6q4l2-mz.121-6.EA2.bin

Seems to be working OK but the unused and unconnected ports report as follows;

FastEthernet0/11 is up, line protocol is down

Hardware is Fast Ethernet, address is 0007.85bf.be8b (bia 0007.85bf.be8b)

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)

Full-duplex, 100Mb/s

input flow-control is off, output flow-control is off

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output 11w1d, output hang never

Last clearing of "show interface" counters 3w0d

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

0 packets input, 0 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 input packets with dribble condition detected

0 packets output, 0 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

I would expect the port to be down/down, not up/down.

Any thoughts out there?


Hall of Fame Super Silver

Re: Interface Trouble?


Why would you expect an unused interface to be down/down? When we talk about interface state the first part represents the hardware state of the interface (from a hardware perspective, is the interface working) and the second part represents the protocol state of the interface (does it have layer 2 connectivity). If the interface passes the various hardware checks that the box performs it will report the interface state as up. If keepalives fail it will report the protocol state as down.

So if the interface passes the various hardware tests why would the interface state not be up?



New Member

Re: Interface Trouble?

Just basing on my experience with the 3500 series switches. If an 3500 series FastEthernet interface is not connected, it reports down/down. So, a new "feature"?