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New Member

Fast Ethernet Interface up/down

I canot seem to get a fast ethernet interface to work on my 7206. I have it connected to a laptop with a crossover cable, config :

interface FastEthernet5/0

ip address

ip route-cache flow

ip ospf network non-broadcast


FastEthernet5/0 is up, line protocol is down

Hardware is DEC21140A, address is 0003.e454.208c (bia 0003.e454.208c)

Internet address is

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 128/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Half-duplex, 100Mb/s, 100BaseTX/FX

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

Last input never, output 00:00:04, output hang never

Last clearing of "show interface" counters 00:53:08

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

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

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

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

0 watchdog

0 input packets with dribble condition detected

319 packets output, 19140 bytes, 0 underruns

319 output errors, 0 collisions, 0 interface resets

0 babbles, 0 late collision, 0 deferred

319 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

Laptop set up with IP address in subnet, default gateway is interface address.

Thanks for any help



Re: Fast Ethernet Interface up/down

Possible causes for a line protocol down on an Ethernet could be a Bad cable or a duplex/speed problem. Can you please confirm that both of them are fine. Whats the duplex setting on your laptop ?

New Member

Re: Fast Ethernet Interface up/down

The laptop works fine when connected to the other fast eternet interface on the router. Both interfaces on the router are in half-duplex due to a 3600 router on the network with an ethernet interface. (soon to be removed). And the crossover cable tests good. Perhaps I should connect the interface to a switch first?


Re: Fast Ethernet Interface up/down

Yeah, that would be a good idea. Check if the port works fine with a switch or with any other equipment. Another thing, try giving no keepalive on the router and see if theline protocol comes up ( without connecting any cable), if it comes us then connect the laptop and see if you can communicate.


New Member

Re: Fast Ethernet Interface up/down

When i disconnect cable from router interface and set no keepalive interface comes up. Can you explain why this is. I am looking around for a switch in the mean time.