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Connecting multiple companies

Hello everybody

Need your help with this project because it's causing some problem when connecting the switches together

The visio drawing has TC1, TC2, and TC3 connecting to each other by a straight through cable on TC1, TC2, and trunking from TC1 to TC3 and everything works great on VLAN1/VLAN2

We also have another network with GADRSW00 /CS1_3750_Stack and both connect using a trunk port as to bring all Vlans from CS1_3750_Stack to GADRSW00 and this works great


I need to connect the TC1, TC2; TC3 switches to GADRSW00, CS1_3750_Stack to allow users access to resources on the other networks, as you see the GADRSW00 switch is on the same subnet as TC1 but on different VLAN names with TC1 using Vlan 2 and GADRSW00 using Vlan 193. What’s the best way for connecting them together without cause problems, what’s the best way for connecting CS1_3750_Stack to TC1, TC2, TC3 switches, can route everything to GADRSW00 through as both are connected through the same subnet on 10.1.1.x network


Thanks for showing the best way for doing this


Hello.You have duplicate VLAN


You have duplicate VLAN ids between TCx and 3750 Stack, that is why you either:

- need to change VLAN ID (before merge),

- or you may enable routing  on TCx and build L3 interface between TCx and 3750.

The 192.168.0.* network

The 192.168.0.* network exists on both GARDSW000 and TC1 and you have the same VLAN ID's on both sides.

Realistically you have two options:

1. Connect GARDSW001 and TC1 together using a Layer 2 Trunk - This means you will need to change the VLAN ID's on both sides so they are unique which is quite a faff, especially if its a live network.

2. Connect GARDSW001 and TC1 together at Layer 3  - The 192.168.0.* network exists on both sides so you are going to need to change the IP subnet on one side otherwise the routing is not going to work properly for this subnet.

I would go with option 2 and use EIGRP.



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