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New Member

cisco 3750 FastEthernet question

Hi all,

I have a sorta silly question here. I just got a 3750 and all of the ports say they're part of FastEthernet3. So to check port 48, I would type:

sh int fa3/0/48

I was expecting to have it be FastEthernet0.

I figure this is because of the Stacking options available with this model. I'm not so bothered\curious about the fact that there are 3 options available (one for device\slot\port), but more that it's fa3. Not fa0. If this were the 6500 or 9500, it would be just fine and what I expected. I'm really only working with smaller switches these days (ie 2900s, 3500s) so was surpirsed to see this.

Also, this is a repurposed switch I got from a company that we have  split off from. So it could potentionally be part of a stack previously.

Can anyone tell me why it's FA3? Or point me at some documentation to learn more?

I've spend about 30 minutes trying to search on here and The Google, but have no answer yet. It's probably not a big deal but go me really curious and wondering if I need to do anything to this switch beforehand. I wiped the config to start as well.

Thanks,

Ted

Everyone's tags (3)
1 ACCEPTED SOLUTION

Accepted Solutions
VIP Super Bronze

Re: cisco 3750 FastEthernet question

Hi Ted,

Have you tried this command?

Remove a Provisioned Switch from the Stack

If a switch stack runs Cisco IOS Release 12.2(20)SE or later and you  remove a provisioned switch from the switch stack, the configuration  associated with the removed stack member remains in the running  configuration as provisioned information. In order to delete all  configuration information associated with the removed switch (a stack  member that has left the stack), apply the no switch provision command in global configuration mode.

In this example, switch number 2 was removed from a stack. The model number of the switch is WS-C3750-48TS:

3750(config)# no switch 2 provision ws-c3750-48ts3750(config)# exit3750# write memory

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml#stack5

HTH

4 REPLIES
VIP Super Bronze

Re: cisco 3750 FastEthernet question

Hi Ted,

Have you tried this command?

Remove a Provisioned Switch from the Stack

If a switch stack runs Cisco IOS Release 12.2(20)SE or later and you  remove a provisioned switch from the switch stack, the configuration  associated with the removed stack member remains in the running  configuration as provisioned information. In order to delete all  configuration information associated with the removed switch (a stack  member that has left the stack), apply the no switch provision command in global configuration mode.

In this example, switch number 2 was removed from a stack. The model number of the switch is WS-C3750-48TS:

3750(config)# no switch 2 provision ws-c3750-48ts3750(config)# exit3750# write memory

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00807811ad.shtml#stack5

HTH

New Member

cisco 3750 FastEthernet question

Sorry for the delay. I was looking at the response and about to reply when I got pulled away from the office suddenly.

That info pointed me in the right direction, Reza. Thanks!

I guess it's more of my lack of knowledge of stackable switches than an actual problem. I was unable to remove any switches because it was a standalone and master. However, I was able to go in and change the switch from #3 to #1.

c3750(config)#switch 3 renumber 1

What was throwing me off is that it retains the Stack number when you wipe the memory, reload, and go through the setup process. I wasn't expecting that. So having it be switch #3 from the start seemed off (ie after a 'Write Erase').

In searching around there doesnt seem to be a way to remove or disable the stacking feature. Not that it's a problem or anything.

One related question:

Why does it have 3 number variables for the 3750 as in fa1/0/1 for port 1, instead of just fa0/1 or fa1/1? I am not sure why it has switch\slot\port when only switch\port are used.

Thanks,

Ted

VIP Super Bronze

Re: cisco 3750 FastEthernet question

The switch port numbering usually starts from 0.  For example, if you look at the 3560 series, the ports are 0/1, 0//2, 0/3 etc...  Now in a 3750 case Cisco just added a number in front of it to make 1/0/1 2/0/1, etc for the switch number in the stack, if not the port numbering from one switch to another can be confusing. Also, in the case of 3750 series the middle 0 is not really used, but there are other cases that the middle number is actualy used.  For example if you created a VSS pair using 2 6500 switches, since the 2 switches logically become one, the port numbering would be 1/1/1,this means switch 1, blade 1 and port 1 or 2/4/6 means switch 2 blade 4 port 6

HTH

New Member

cisco 3750 FastEthernet question

Cool thanks for that info.

Yeah, I was expecting 1/1 and 2/1 to access port 1 on 2 different switches in a stack, not 1/0/1 and 2/0/1. Makes sense with the 6500 and 9500 which I used to work with.

Thanks for all your great answers up here, Reza. I was search for the answer to something completely unrelated and you had answered that one as well.

Thanks!

Ted

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