Extending Network across the WAN with Vlans

Unanswered Question
Jun 18th, 2008

Hi there

here is the scenario. My customer is currently moving its head office location to a temporary one to refurbish the existing building. We need to move all servers etc to this new location in a timely fashion without disruption. we have four VLANS in the current network and at this time our WAN provider cannot pass VLANS through thier WAN infrastructure.

the question is, how can we work around this temporarily (We need to maintain exact ip addressing, gateway etc as if they were in the existing location) the time to completely move from one location to the other is about two months, meaning every week, one or two servers will be moving.

we were thinking of two options,

1. bridged network - not too sure about the vlans

2. enable single WAN ports for each VLAN - very very expensive

any assistance would be greatly appreciated.

thanks in advance

I have this problem too.
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Paolo Bevilacqua Wed, 06/18/2008 - 11:02

You can try with bridging over GRE tunnels. The details for the config depends on you exact setup, but generally you will need one separate tunnel for each vlan (use tunnel id to differentiate). It can be a little tricky to setup, but should work.

merryllem Wed, 06/18/2008 - 13:10

Per your requirements l2tp is the technology you should be looking into. What type of router are you using to terminate you want connections (on both locations). There are limitations l2tp depending on the hardware you are using.

a.gooding Wed, 06/18/2008 - 13:23

we were actually looking at 2 3560 switches.

Our timeline is about two weeks for everything. GRE sounds good but we've never done it to be honest and that timeline is kinda tough for us to swing that.

im thinking we would just enable extra ports from the provider and go with that.

Paolo Bevilacqua Wed, 06/18/2008 - 13:48

You have an alternative anyway. For the duration of the move, change all ports to vlan 1. Configure the secondary address for all subnets on svi1 interface.

The biggest issue can be dhcp if you have multiple servers, phones, etc. But unless there is something special in the network, it will work.

d.chulhan Sat, 07/05/2008 - 22:07

If you are still working on this. The GRE tunnel is a great idea (perhaps with vrfs). Otherwise if security is not a priority over the WAN, sub-interfaces would for you. You can just re-create the VLANs on the remote side and match them (if you must).

a.gooding Wed, 07/16/2008 - 05:47


i just enabled separate ports on the FLOW switches for the different Vlans. this was just for the move (1 week) so that was the easiest thing to do.

everything is fine now

thanks for the response.


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