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New Member

Connecting 2 bulding with different VLAN

Hi,

Currently, there are 2 different building running on separate VLAN, which want to merged (meaning they want to be able to connect to each other via a fiber link)

1) Building A - flat LAN, with 2 subnets

2) Building B - multiple VLAN exists (L3)

May I know, what's the recommended method to merge this 2 network.

Thanks.

7 REPLIES
Purple

Re: Connecting 2 bulding with different VLAN

Hi,

One very simple way is to configure a new VLAN on the switch in Building B and then make the port on that switch that connects to Building A an access port in that VLAN.

That method will result in the least amount of configuration effort.

You will also need to enable inter-vlan routing on the switch in building B if it is L3 capable. Otherwise, you will need a router to do so.

Pls do remember to rate posts.

Paresh

New Member

Re: Connecting 2 bulding with different VLAN

i thought the best way, will be mirroring the VLANs in building A & B (ensuring both buildings having the same VLAN) and create a trunk between them.

Purple

Re: Connecting 2 bulding with different VLAN

Oh okay, I had assumed that the traffic in building one was supposed to be for a distinct VLAN.

But if you wish to merge them, then I agree that you need to mirror the VLANs in building A, create a trunk on the link between them and perform inter-vlan routing to get between the VLANs.

Pls do remember to rate posts.

Paresh

New Member

Re: Connecting 2 bulding with different VLAN

i've another question, with the new VLANs being created for both buildings, will the traffic be a lot (coz i don't want unnecessary traffic to pass thru).

secondly, i know a vlan can have multiple ip subnets, but does that apply to hsrp also??

Purple

Re: Connecting 2 bulding with different VLAN

To minimise the amount of unnecessary traffic over the trunk, I would recommend that you configure both switches for inter-vlan routing so that that can be done locally if the source/destination are at the same site.

You can use HSRP with secondary IP addresses as it does support multiple subnets per VLAN.

Pls do remember to rate posts.

Paresh

New Member

Re: Connecting 2 bulding with different VLAN

meaning i've to create all hsrp on all the L3 for both buildings..

below are valid ??

int vlan 1

ip add 10.10.10.1 255.255.0.0

ip add 20.20.20.1 255.255.0.0 secondary

standby 1 ip 10.10.10.254

standby 1 ip 20.20.20.254 secondary

Purple

Re: Connecting 2 bulding with different VLAN

Yes, that would work.

Paresh

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