EIGRP in MPLS Layer 3 VPNs

EIGRP, or Enhanced Interior Gateway Routing Protocol, is used in MPLS (Multiprotocol Label Switching) Layer 3 VPNs to establish peering between Customer Edge (CE) routers and Provider Edge (PE) routers. This creates a peer-to-peer VPN architecture where the Provider Core remains transparent to the customer. It's important to note that MPLS L3 VPNs do not imply encryption; they are primarily used for routing and isolation.

MPLS Key Terminology

• CE (Customer Edge): CE routers are typically managed by the customer and serve as the customer's network edge devices.
• PE (Provider Edge): PE routers are located at the boundary of the service provider's network and terminate multiple customer connections. They act as entry points for customers into the provider's network.
• P (Provider Core): P routers are located within the core of the service provider's network and have no direct or physical customer connections. They route traffic between PE routers.

MPLS Layer 3 VPN architecture enables service providers to connect multiple different clients securely and efficiently.

Configuration in the MPLS Core

Configuring EIGRP in the MPLS core involves setting up EIGRP routing within the service provider's network. This ensures the proper routing of traffic between PE routers and the MPLS core.

MPLS MP-BGP Configuration

Multiprotocol BGP (MP-BGP) is a key component of MPLS Layer 3 VPNs. It is used for distributing VPN routes across the provider network and is a fundamental part of the VPN architecture.

CE Peering to PE via EIGRP

Customer Edge (CE) routers peer with Provider Edge (PE) routers using EIGRP. This enables the exchange of routing information between customer sites and the service provider's network.

Communication of EIGRP Values Across the Provider Core

The communication of EIGRP values across the provider core is essential for proper routing within the MPLS Layer 3 VPN. The core routers need to understand and propagate EIGRP routing updates between PE routers.

Verification

To verify the MPLS Layer 3 VPN configuration and operation, use the following commands:

• mpls ip: Verifies the MPLS IP configuration on the router.
• show mpls ldp neighbor [detail]: Displays detailed information about MPLS LDP (Label Distribution Protocol) neighbors.
• show mpls forwarding-table: Shows the MPLS forwarding table, which contains label information for routing.
• show mpls ldp bindings: Displays MPLS LDP bindings, showing how labels are associated with prefixes.
• show bgp vpnv4 unicast vrf [vrf name] [prefix/nn]: Shows BGP VPNv4 unicast routes within a specific VRF (Virtual Routing and Forwarding) context.

Configuring EIGRP in MPLS Layer 3 VPNs is crucial for establishing routing connectivity between customer sites and ensuring proper data transmission across the provider network. Use the verification commands to confirm the correct operation of the MPLS VPN configuration.