MPLS L3 VPN Configuration

• PE-CE Routing
  • No MPLS Required
  • Normal IPv4 and IPv6 routing
  • All IPv4 protocols supported.
  • Some IPv6 protocols supported.

• MPLS Core (P and PE) Devices
• IGP + LDP
  • goal is to establish LSP between PE /32 Loopbacks.
  • Traceroute between loopbacks for verification.
• Other label switching mechanisms are available but outside of CCIE Scope.
  • BGP + Label, RSVP-TE

• MPLS Edge (PE) devices
  • VRF
    • VRF aware PE-CE Routing
    • Used to locally separate customer routes and traffic.
  • VPNv4 BGP
    • iBGP peering to remote PE /32 Loopbacks.
    • Separates customer control and data plane over MPLS core.
    • Other designs supported outside scope of CCIE.
      • VPNv4 RR, Multihop EBGP VPNv4, etc.
  • Redistribution
    • VRF to BGP import and export policy

• VRF

1. Create a VRF name that’s unique to the box.
2. Then we’re creating a Route-Distinguisher that makes the prefix unique.
3. Then we’re defining the Route-Target import and export policy.
   1. ie – anything in VRF A being advertised into BGP is getting the extended community added to it of 100:1, which is then getting advertised with a modified IPv4 prefix. An IPv4 VPN prefix.
      1. ie. export.
   2. The other way around, anything that comes into this router with a route-target of 100:1 will be imported into VRF A.
      1. ie. import.

• VPNv4 BGP

The command ‘neighbor 7.7.7.7 send-community extended’ allows us to send the route target extended community option. The command is also enabled by default after we run the activate command.

• Redistribution

May be needed if the customer is using IGP like OSPF but needs their WAN routes added into their internal routing domain. If the CE is running BGP to the PE however, then redistribution obviously not needed.