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Cisco Catalyst 3750 Port is Error Disabled

Posted on 2010-11-19
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Last Modified: 2012-08-13
Good morning.
I have a Cisco Catalyst 3750 PoE switch that I'm trying to connect to a NetGear GS748T via the SFP (GBIC) ports (Gigabit uplink). I have purchased the necessary adapters and cable, but when I connect the two switches, the Cisco 3750 shows that the "port is error disabled." On the GUI interface, there are two SFP/GBIC ports (Gi1/0/1 & Gi1/0/2). Port 1 is lit up green and is connected to a different switch. Port 2 is yellow and displays a "port is error disabled" message.

I'm not real familiar with the CLI for this particular switch. I was hoping there is a way to figure out why the port is error disabled using the GUI interface. I have some possible thoughts, but haven't been able to find info on these as of yet:

1) Do the SFP/GBIC ports share a spot with other ports on the switch? For example, on the GS748T, the use of the SFP port disables Ethernet port 48 on the switch. Does the same hold true on the Cisco 3750?

2) Can both SFP/GBIC ports be used simultaneously? It would seem they would not be on the switch if they couldn't both be used at the same time.

Any help or guidance you can provide would be helpful.
Thanks in advance.

J
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Question by:brownmetals
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16 Comments
 
LVL 24

Expert Comment

by:Ken Boone
ID: 34173734
Yes all sfps can be used simultaneously.  Log into the swith and do this
term mon

This lets you see the logging messages on the console

then do a shutdown on the err-disabled port
then do a no shutdown on that port.

The port will either come up normal or it will immediatlely go back into err-disabled state.  If it does you will see the message as to why.   If you have bpduguard enabled it would do this if the netgear is sending bpdu packets.  In that case turn off bpduguard
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Author Comment

by:brownmetals
ID: 34173992
@kenboonejr

Thanks for the info. I'm not real familiar with the CLI, so I don't know the precise syntax for performing a shutdown of the port. The only way to do it in the GUI is to uncheck the "Enabled" box next to that port. However, it's already unchecked (disabled) and when I enable it, it just reverts back to being disabled. Actions performed in the GUI don't display messages in the CLI. Can you explain in more detail how I would disable and enabled that port?

Thanks,
J
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LVL 24

Expert Comment

by:Ken Boone
ID: 34174320
So I can explain the CLI

telnet or ssh into the switch or just console into the switch

login

then do this
----------------
term mon
config t
interface gig1/0/x    - where x is the port on the switch
shutdown
no shutdown
exit
exit

------------------


Also do this command and paste the results:
show run int gig1/0/x    - where x is the port on the switch in question

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Author Comment

by:brownmetals
ID: 34174400
Here's the results:

CS3750PoE(config)#interface gig1/0/2
CS3750PoE(config-if)#shutdown
43w3d: %LINK-5-CHANGED: Interface GigabitEthernet1/0/2, changed state to administratively

CS3750PoE(config-if)#no shutdown
CS3750PoE(config-if)#
43w3d: %GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port 65538 has bad crc
43w3d: %PM-4-ERR_DISABLE: gbic-invalid error detected on Gi1/0/2, putting Gi1/0/2 in err-disable state
43w3d: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/2, changed state to downexit
CS3750PoE(config)#exit


show run int gig1/0/2 results
=======================


CS3750PoE#show run int gig1/0/2
Building configuration...

Current configuration : 38 bytes
!
interface GigabitEthernet1/0/2
end

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Author Comment

by:brownmetals
ID: 34174639
I guess the question now is if this SFP module is compatible with this switch.

SFP Model: MGBSX1
Switch: Catalyst 3750 with IOS Version
Cisco IOS Software, C3750 Software (C3750-IPBASE-M), Version 12.2(25)SEB4, RELEASE SOFTWARE (fc1)

Is this a compatible SFP module? Is there a different one I should be using?

Thanks,
J
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LVL 24

Expert Comment

by:Ken Boone
ID: 34175377
Well issue this command:

show interface status  

When you get to that sfp it will tell you something about it.  My guess is that it is not compatible.  If you stick with a cisco sfp you won't have a problem.
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Author Comment

by:brownmetals
ID: 34175480
Here's what it comes up with:
Gi1/0/2                      err-disabled 1            auto   auto Not Present

Now that I look more closely, I believe the SFP module is designed only for Cisco's Small Business line of switches. It works perfectly with the Cisco ESW-540 24-port switches and it also works with the Netgear GS748T.

Here's what I was trying to do:

Cisco ESW-540 switch connects to a 2nd ESW-540 switch using SFP. One of those ESW-540 switches also connects to GB Port 1 on the Cisco 3750 (it must be using a different SFP module). I was trying to take GB Port 2 on the 3750 and connect it to the NetGear switch. Instead, I connected the NetGear switch to one of the ESW-540.

All network paths can be accessed. All devices on any of the 4 switches can access any of the other devices.

I guess what I'm not sure about is if this is the ideal setup. Yes, everything works, but could it be optimized by having a GB connection between the 3750 and the NetGear switch? I'm not sure it will make that big of a difference, but tried it anyway to find out these SFP modules aren't compatible with the Cisco 3750.

For now, everything works. I look forward to any additional feedback you may have.

Thanks,
J
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Accepted Solution

by:
Ken Boone earned 500 total points
ID: 34175615
Yes I have seen the incompatibility of the small business switch sfps and the 3750 switches.  So basically you have a chain of 4 switches.  I would have the 3750 be the root/core switch and the other 3 switches each directly connected to the 3750.   So there would only be 2 hops to get from any one switch to another.   That is what I would do.

Having said that if they are all gigabit switches and your network is like most networks, you aren't using but maybe 10% of the bandwidth at any given time tops, so you would most likely not see any noticeable difference doing it my way.  Technically it is better and more efficient but on the scale of things you won't visibly see a difference.

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Author Comment

by:brownmetals
ID: 34175763
You said something that "made the light go on.:" No more than 2 hops.

Unfortunately, the 3750 is a 10/100 PoE switch and only has (2) GB ports. All the other switches, however, are GB switches with (4) SFP/GB ports each. Because I don't have the correct SFP module for the 2nd GB SFP port on the 3750, I can still make it work with the existing hardware.

Netgear GS748T - has printers & servers only
Cisco 3750 - has Wireless access points & some IP phone/PC users
ESW-540s - have PC & IP Phone users

Connect existing SFP from Cisco 3750 to Netgear switch
Connect NetGear switch to 1 of ESW-540
Connect NetGear switch to 2nd ESW-540
Connect ESW-540 to 2nd ESW-540

Same idea of limiting hops, but just organized with the NetGear switch at the root since it has (4) available SFP/GB ports and contains all servers and printers.  I think that will be the best use of the resources I currently have. Does that seem feasible?

Thanks,
J
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Expert Comment

by:xzatech
ID: 34176009
the problem is the incompatibly .. what the the brand of the spf
if it not a Cisco then you need to implement this command in global config mode 8"service unsupported-transceive"*
then do shut , no shut on the port
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Author Closing Comment

by:brownmetals
ID: 34176239
The SFP modules for the ESW-540s work well with the NetGear switch as well. They are Cisco SFP modules. They just don't seem to work with the 3750. The SFP module I currently have in the 3750 is one I purchased back in 2006 and I can't seem to find the exact model number. Anyway, I think we have a solution that will work. Thanks again for your input.

J
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Expert Comment

by:xzatech
ID: 34176378
well what was the solution ?????
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LVL 4

Author Comment

by:brownmetals
ID: 34176513
The SFP module I have is incompatible with the Cisco 3750 switch. I'm using the ideas presented to reorganize the way the switches are connected so that no device is more than 2 hops from another device.
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Expert Comment

by:xzatech
ID: 34176639
by any chance are you using "champion SFP"
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LVL 4

Author Comment

by:brownmetals
ID: 34176652
No, they're Cisco SFP modules

SFP Model: MGBSX1
Switch: Catalyst 3750 with IOS Version
Cisco IOS Software, C3750 Software (C3750-IPBASE-M), Version 12.2(25)SEB4, RELEASE SOFTWARE (fc1)

They're just designed for their small business line of switches like the ESW-540. I didn't realize that when I purchased it.
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Expert Comment

by:xzatech
ID: 34177253
thank you..
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