Moving routing from perimeter Router to 3750x

[mike-elliott]

I have an 1811 with several subnets connected to it.

I recently installed a 3750x plant and want to bring my interior routing back to it.

All the routing is handled by the 1811 via secondary interfaces on vlan1

I have 192 ports, and subnets show up on almost all of them.  None of the ports are assigned to any specific vlans.  Most ports have several subnets on them.

What is the best approach to getting the 3750x to handle the routing?

Thanks

[ALIAOF_]

If you have VM's with multiple subnets connected to the ports then you will need to configure those ports on the switch as trunk ports.

[Joseph W. Doherty · Accepted solution]

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

Perhaps the "easiest" thing to do would be to transfer all the gateway IPs to a single SVI on the 3750-X.  In effect, mimicking what you have now on you 1811.  If you still need the 1811 for other routing, e.g. WAN, then you'll likely need to reconfigure how the 1811 and 3750-X interact; various ways you can do that.  For example, you could have the 1811 and 3750-X with interface on all your subnets, or you could set up a L3 transit link between them and route between them.

[mike-elliott]

That's what I was getting to I think.  Then it would not matter what subnets appear where, it would route them all.  Or am I misunderstanding how the L3 routing works on a switch stack?

My plan is to use another subnet for the "routing" network.  All of my perimeter routers will be configured on this subnet.  Then I create a SVI for my internal subnets.  These internal subnets *should* be able to be seen on any interface.  We don't need port security or anything like that here.

[ALIAOF_]

You still need the port configured for the same VLAN host is on or as a trunk if there is a VM with multiple subnets.