Based on the objective set, you come up with the following solution:
Once setup has been completed, the following will happen:
- You will be providing site-to-site connectivity
- Connectivity into your core is provided by two different carriers, VM and COLT respectively
- You will also be providing Internet DNS resolution; though Internet access is still kept as before, through the initial provider
- You will not be responsible for NAT
I . SETTING THE MPLS L3VPN
1. Configure MPLS in your core – this has been done already
2. Configure BGP/MP-BGP between all your PE routers – see configuration snippet below for PE1 router; PE2 and PE3 routers will have similar configuration
3. Creating the Virtual Router – this is done by using the ip vrf <vrfName> command. Initially, this virtual router will have no interfaces attached
Each PE router is configured with a “local” route-target which will be added/exported into outgoing BGP updates. Above, you can see the configuration for PE1, PE2 and PE3 respectively. Furthermore, each PE router will also import routes coming in BGP updates which match the route-target set in the route-target import <rt> command.
If you look at the PE1 configuration, it reads as below: “My local route-target is 65000:1 and I will set this BGP attribute on all outgoing BGP updates. I also accept BGP updates and will import into this VRF/VPN/Virtual-Router all routes which have the Route-Target attribute set to 65000:2 & 65000:3”.
4. I will now attach interfaces to our router – if you look at the network diagram above, it becomes clear that the interfaces I will be attaching are are the ones facing the customer
5. Since the PE can have multiple VRFs/VPNs, we need to, somehow, separate each VPNs routing domain – so we need to have a separate routing table for each VPN. Once the routing-table has been created, all we need to do is redistribute routes into the BGP process attached to the VRF – so let’s set this up:
6. So we now have the routing process into which we’ll be importing routes. We also defined the criteria for importing & exporting routes to/from other PE routers with which we peer. We’ve also create the Virtual router by means of a VRF and attached interfaces to it. Next, we create the actual routes we want to import & export:
We have now concluded setting up the MPLS based L3VPN.
II. SETTING THE MPLS DNS SERVICE
For DNS functionality, I’ve used the following commands:
Flip to the next tab to see test results …