Was hoping for some advice regarding an OSPF solution for a customer.

Basically the customer has about 4 sites.

These would all be linked together physically.

I have attached a basic network diagram.

Which can be viewed here

As you can see there is several redundant layer 2 links between the sites.

Each site has an NTU.

At the DC there is an access switch which has a trunk to a core router.

This core router has an uplink to the ISP.

When ordering a connection from the ISP we get a VLAN tag and configure a VPLS ID and matching VLAN ID on the router and switch.

The NTU on each site uses a separate VLAN ID that we use for monitoring purposes.

Can we use the one public IP address and the ISP defined VLAN tag for every customer location (their WAN traffic)?

To do this I was going to install a router in our rack at our DC with an OSPF instance running on it. This router with a private IP address would be the default route for all CPEs. Then on this router I would configure its own default route to the ISP gateway. It would be connected to the access switch which is connected to our core router with ISP defined VLAN tag.

Would this work? It seems abit messy, I was wondering if anyone could give me any feedback.

Please let me know if anyone needs anything clarified and thank you for your assistance!


Hey everyone I have added a diagram for the internal data center connection for clarity purposes:

CORE diagram

  • 1
    The devices in your diagram aren't labeled according to the text, so it's hard to see how it matches. The links in the diagram look like L3 links. Where is the DC?
    – Ron Trunk
    Dec 13, 2016 at 2:36
  • Hi Ron, The DC is called Equinix which is the router in the middle. It should technically look like a cloud. The links are the red lines which have private IP addresses assigned to them so you can route over them. Dec 13, 2016 at 2:47
  • Seems simple enough based on the information you've provided.
    – Ron Trunk
    Dec 13, 2016 at 2:53
  • the actual OSPF connectivity for each CPE is simple enough, it's the upstream connectivity I have asked about... Dec 13, 2016 at 3:08
  • I guess I'm not seeing the issue. What part are you having trouble with?
    – Ron Trunk
    Dec 13, 2016 at 3:10


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