Solved: New 2960 Switch Can't Connect to Media Converters - Page 2

Ed Willson · ‎06-11-2012

I just installed a new 2960 to replace a 3550 this last weekend. All of the fiber media converters will not connect to the new switch. The converters are made by Black Box and Desa. If I plug them into the 3550 they link up immediately. If I plug them into the 2960 there is no link whatsoever. Any ideas? I've tried letting it auto-negotiate and tried turning off inline power on the 2960 with no luck.

2960:

FastEthernet0/5 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 0022.91f6.aa05 (bia 0022.91f6.aa05)

Description: Mazak

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

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

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Half-duplex, 10Mb/s, 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 never, output 00:38:25, output hang never

Last clearing of "show interface" counters 01:39:39

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 multicasts)

0 runts, 0 giants, 0 throttles

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

0 watchdog, 0 multicast, 0 pause input

0 input packets with dribble condition detected

31448 packets output, 3530944 bytes, 0 underruns

0 output errors, 0 collisions, 2 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

3550:

FastEthernet0/40 is up, line protocol is up

Hardware is Fast Ethernet, address is 0009.4347.cea8 (bia 0009.4347.cea8)

MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,

reliability 255/255, txload 2/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Half-duplex, 10Mb/s, 100BaseTX/FX

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

Last input never, output 00:00:01, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

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

5 minute input rate 16000 bits/sec, 8 packets/sec

5 minute output rate 94000 bits/sec, 20 packets/sec

14856 packets input, 2567842 bytes

Received 163 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 watchdog, 13 multicast

0 input packets with dribble condition detected

36506 packets output, 21669837 bytes, 0 underruns

0 output errors, 4339 collisions, 3 interface resets

0 babbles, 0 late collision, 121 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

Thanks,

Ed

Leo Laohoo · ‎06-11-2012

How to use Time-Domain Reflectometer (TDR)

jimmysands73_2 · ‎06-12-2012

Ahhhh.....if the same ethernet cable works (from the media converter) to a 3560, but wont provide link on a 2960, would it be the cable? Not only that, the OP says that he has multiple cables, all showing the same no link, could that be a cabling issue? Hopefully the OP will post the end results. Especially because I work with media converters daily, so I might see this down the road

Ed Willson · ‎06-12-2012

Yes. The only thing that changed was the switch. Ports were set up exactly as the old ones were. One thing - this is only happening with the 10 half connections. I'll let you know what I can find out when I get back.

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Leo Laohoo · ‎06-12-2012

this is only happening with the 10 half connections.

Can you try this interface command:

conf t

interface f0/5

speed auto 10

end

Ed Willson · ‎06-12-2012

I'm traveling for the next day or two. I'll let you know what I come up with. I have a microscanner2 from fluke that gives me line conditions. Is this like the TDR?

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Ed Willson · ‎06-15-2012

I disabled errdetection on the new switch as I noticed one of the ports in an err disabled state, but that didn't help so I re-enabled it.

So I did manage to get the connections working on all 4 pieces of fiber that I was having trouble with. i'm not sure what the root cause was though. All 4 media converters were pretty old. I replaced 2 of them with 100BaseT converters at both ends, that brought those connections up. For the other 2 that have controllers build into the machines I grabbed a couple brand new 10BaseT converters and hard set the duplex on the new switch for them.

I tested all of the media converters I replaced and they all were still working with the old switch. I'm not sure what other differences there are in the new switches and the old ones...But at least they are all working again and I was able to fully document the connections.

Thanks,

Ed

jimmysands73_2 · ‎06-15-2012

Thanks for the update Ed.

I am inclined to believe it was speed/duplex mismatch somewhere in the chain. But ultimately glad you got it working, and I am sure you are too! Woohoo!!

Ed Willson · ‎06-27-2012

Jimmy - I'm inclined to believe you're correct, but without access to and hard knowledge from the other end of the chain I can't comfirm.

Thanks all for the help!

kendallcrews · ‎01-03-2017

I know this is a very old thread, but I just ran into and fixed a similar problem and wanted to document it somewhere, in case someone else finds their way here like I did. :)

My connection looks like this:
(device)-----(converter)=====(converter)-----(switch)

In my case, the converters are both GarrettCom Magnum FT14H. They are 10mbps converters with link pass-through enabled.

This connection worked fine when the switch was a 2950, so long as the switchport speed was set to 10. But like the original post, I could not get a link light on a CGS 2520.

Long story short, my solution was to force speed to 10, duplex to full, and disable PoE. The port did have to be rebooted after setting these.

conf t
int fa0/17
speed 10
duplex full
power inline never
shut
no shut
end