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Our data centre provider operates 2 sites, and we currently have equipment in one and would like to have equipment in the second. They've told me that they operate a layer 2 vlan between the 2 sites over a 20gbit connection, and that they'd just give me ethernet cable at each end to connect the locations.

At the current site, we have Cisco 2960 48TC-L switches, all the machines are on a 192.168.x.x subnet and we have cisco firewalls with which we connect to our internet provider with.

My question is what would I need to do to connect the 2 sites? could I just plug the ethernet cables the provide into the cisco switches, and have the same switches the other end? would I need to set up a separate internal network on the other side and connect both through the firewalls? Would the cisco switches need special configuration?

We expect to maintain a number of connections between the 2 sites, and each site would have its own internal dns name like

Sorry if I'm being vague or haven't included enough information, I've a fairly good knowledge of hardware but we're down a netops guy at the moment and I'd like to get both sites on-line ASAP!

Thanks in advance!

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up vote 3 down vote accepted

If they told you that they operate a layer 2 vlan between the 2 sites it probably means that if you plug the cable on the Cisco Switch and both side, you will be in the same network. The best is to ask your data centre provider.

Then you have to think of your needs, may be you don't need any L2 connectivity between both DC and in this case you can create 2 different L3 networks.

You also probably want to take a look on how public IP are managed (public IP on both DC or public IP on 1 DC with failover to the secondary DC in case of failure)

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As long as the Ethernet cable they give you is forwarding you untagged vLan traffic, you can just plug it in and it'll look like one very long Ethernet cable to your switches.

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If it is truly a layer 2 VPN then both sites could be on the same network and you should not need any sort of router connecting your two sites together. Of course, one downside to this is that you would be sending broadcast traffic across your WAN link which, in my mind, is not ideal, but according to your statement, you said it is a 20gbit connection, so does that really matter?

My instincts say segment the two networks but that could just be that I am slow to adapt to the modern world of such high speed WAN links.

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Who said anything about a VPN? – Chris S Jun 2 '10 at 0:25

You can also consider VPLS, ATOM and/or EoMPLS technologies which will allow you to do this.

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is it in different loactions ! i assume that your SP should provie to you a specific vlan and associate a techonlogy called "qnq tunnel" that mapping to your multiple VLAN on your both DC to one Vlan on SP.

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