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New Member

Can't bring up interfaces 13-24 on 3750 switch

GigabitEthernet1/0/17 is down, line protocol is down (notconnect)

I've run shutdown and no shut and still no luck. Was working fine as of yesterday.

New Member

Re: Can't bring up interfaces 13-24 on 3750 switch

We have had that here but it was only 4 ports. They are grouped in some fashion on the backplane and if something goes wrong there you will get this behavior. Depending on where in the backplane the issue is you will get one or more ultiple groups of ports flaking out. You could try restarting to see if that fixes it but it likely won't. We had to have ours replaced, good thing we had smart net.

Cisco Employee

Re: Can't bring up interfaces 13-24 on 3750 switch

If you already did a shut/no shut on the interfaces and did not have an impact, then this could very well be related to hardware. If you can move the cable to a different port (one that is working) and make sure that its the port, then you could try reloading the switch and see if the problem goes away. But, I would do this in a maintenance window just to make sure that I dont run into any surprises :-)



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New Member

Re: Can't bring up interfaces 13-24 on 3750 switch

Unfortunately, ports 1-12 are used up for another Vlan. 12-24 is open. All of them have apparently gone bad. I can't get a link light on any of them. I could try to knock one user off and see if I can move a working port into this secure vlan.

You're right....a maintenance window is fine. We have one scheduled for tomorrow, but it didn't involve the switch. I'm sure it's the hardware. Of all days, the boss is out sick.


Re: Can't bring up interfaces 13-24 on 3750 switch

even if it comes up after a reboot, you're not guaranteed that it won't happen again.. this definitely sounds like a problem with the backplane as one person suggested.. You should really call Cisco TAC about this one.

ports 13-24 are most likely all part of the same internal interface and share a single backplane connection.


Re: Can't bring up interfaces 13-24 on 3750 switch

We have seen something like this on a 3750 , I would upgrade the IOS to the latest version and reload it will probably fix it . Before reloading make sure the diagnostics are set as complete for the bootup , if there is a hardware problem then it will probably see it .Reloading the switch fixed it in our case and so far about 2 months it hasn't returned. If its a stack then send the new code to all 3 switches and then change the boot statement .

New Member

Re: Can't bring up interfaces 13-24 on 3750 switch

I don't mind upgrading to latest IOS. I'll check the boss on Monday to see what his ideas are. You hate to be the new guy and make a command decision without clearing it. The good thing is that those ports are empty. We just had a visitor to the building this week that we set up on a secure vlan. The first 12 are on our production network, the last 12 are blank. 12-24 is what is not doing anything at the moment.

Cisco IOS Software, C3750 Software (C3750-IPBASEK9-M), Version 12.2(25)SEB4, RELEASE SOFTWARE (fc1)

Copyright (c) 1986-2005 by Cisco Systems, Inc.

Compiled Tue 30-Aug-05 18:33 by yenanh

ROM: Bootstrap program is C3750 boot loader

BOOTLDR: C3750 Boot Loader (C3750-HBOOT-M) Version 12.2(25r)SE1, RELEASE SOFTWARE (fc)

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