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Connect one cisco as a dummy (simple) switch without trunking??

whoffkne11
Level 1
Level 1

So here is the question and then I will elaborate:  Can I connect a cisco 3750 to a switched and vlaned cisco network and have it run just as a simple or dummy switch and ignore vlan information?

I am a beginning network tech, CCENT certified for a large company.  I have to setup an area of the building with a bunch of workstations where there is only one network port going back to one of the main switches that has all of the company vlan information on it.  Normally we would just add more drops to the area and run the back to the network cabinet and patch them in.  Unfortunately we are in code freeze and cannot open a network cabinet except in an emergency.  Normally, even though we hate doing this, we would connect some small netgear dummy switches to the port for these particular workstations, however, because I need like 24 network ports and I need them soon I would have to order a large netgear or daisy chain a couple 16 porters together.  This is horrible practice and I do not want to do that unless I have no other choice.

What I was wondering is if I can use one of the my old 24 port 3750s with the exact same functionality as a netgear?  The problem right now is if I try to, due to our network settings, the two switches will try to trunk and shutdown the port on my working network switch.  Also, I want it to have the same vlan functionality as the netgear where it will run on the one vlan that the uplink is connected to.  The netgears work perfectly without trunking or messing up the port in the network cabinet, the Cisco switch just ignores it and sees all of the devices connected to it as being connected to that one port.  Can I get my extra Cisco 3750 to function exactly the same or is that just a product of the cisco design?

I hope that I explained that well enough.  I will elaborate if needed.

3 Replies 3

Leo Laohoo
Hall of Fame
Hall of Fame

Delete the config and vlan.dat file.  Ensure all the ports have spanning-tree portfast enabled (except for the uplink).

Are you talking about the uplink on the network side or on the dummy switch side?  The uplink on the network side has spanning-tree portfast as part of our normal settings.

I will run without a config at all?  I thought that I would have to at least build a new config with a hostname and ip and under those settings the ports are all assigned to vlan 1 by default.  Will this create conflicts with the vlan information (as we do not use vlan 1) on the network side?

I am just leary about trying something because if I connect the switch and the settings are not right and they attempt to trunk, the network switchport for disable and I will have to go in and reenable it, which I am not supposed to do during freeze...

whoffkne11 wrote:

Are you talking about the uplink on the network side or on the dummy switch side?  The uplink on the network side has spanning-tree portfast as part of our normal settings.

I will run without a config at all?  I thought that I would have to at least build a new config with a hostname and ip and under those settings the ports are all assigned to vlan 1 by default.  Will this create conflicts with the vlan information (as we do not use vlan 1) on the network side?

I am just leary about trying something because if I connect the switch and the settings are not right and they attempt to trunk, the network switchport for disable and I will have to go in and reenable it, which I am not supposed to do during freeze...

On the active network switch, on the port that connects to your new switch -

int gi0/1

switchport mode access

switchport access vlan 10 <-- assuming l

on your new dummy switch

int gi0/1  <-- connects to active network switch

switchport mode access

switchport access vlan 10

then make the dummy switch VTP transparent (do this before connecting it up) and manually create vlan 10 on the switch.

Jon

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