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New Member

Add 3850 Switch to existing Core Stack


I need to add a 3850 to our collapsed core Current setup - 5-3850 stack switches with vlans and routing enabled.


We are in need of more ports and I purchased a 3850.


I will add the switch to the core via a trunk port

I will make vtp transparent

I will configure the magt vlan 10 with an IP addess.


After this is done, do I make the switch VTP client?

Also, do I turn on IP routing? Or, with the trunk send all packets destined for other vlans over the trunk to the core, and the core will hanle routing?

I am talking about routing between vlans, so user vlan 64 can talk to vlan 64.

I have been doing routing on WAN so long I have forgotten best practices on the LAN and L3 Switching.



Do I simply add this to the switch stack?


Thank you for any help!


Any help is appreciated.


Everyone's tags (1)
Hall of Fame Super Silver

When you add a switch to an

When you add a switch to an existing stack it gets all of its configuration from the stack master.

Just verify it has the same IOS version installed (and doesn't have switch priority set such that it takes over as master) and plug it in via the stacking cables.

If you're adding it as a new access switch then yes just trunk all the VLANs across the uplink to the core. If you have a VTP server setup then set your VTP domain and come up in client mode. If the routing is active on the core and your VLAN SVIs are all there, there's no need for routing on the access layer and the only SVI you need is for management (or use the dedicated management interface for out of band management in its own VRF).

New Member

thank you

thank you