MPLS Laeyer 3 VPNs
- VPNs:
- Customers can connect geographically divers sites across the provider's network
- Traditionally VPN were based on IPsec(layer-3) or TLS(laery-2)
- These 2 were slow & having less features.
- By using MPLS we will overcome these problems.
- With Layer-3 VPNs the service provider participate in the customer's Layer-3 routing.
- Service provider's PE router connect with CE router with L3 protocols
- Layer 2 VPNs: Provider connect the customer site with layer 2 technologies like ATM, Frame-relay or ethernet.
- MPLS Layer 3 VPNs:
- Combines the logic of MPLS tunnels with layer 3 routing information
- PE routers learn customer routes from Customer Edge(CE) routers.
- PE routers advertise customer routes to other PEs via multi-protocol BGP.
- No need to know about the customer route in the middle of the SP network.
- BGP next-hops point to MPLS tunnels
- ex: loopbacks of PE routers
- MPLS L3 VPNs have 2 basic components
- Seperation of customer routing information
- to do this VRF (Virtual Routing & Forwarding) used.
- VRF used on PE routers to keep track on customer routes on per interface basis.
- Exchange of customer routing information.
- to do this MP-BGP is used over the MPLS network.
- Traffice is label switched towards the BGP next-hops.
- The idea of MPLS VPN is
- establishing a full-mesh of dynamic MPLS LSRs between PE routers.
- using these PE routers for tunneling VPN packets across the network core.