A VPRN (Virtual Private Routed Network) instance is the correct service type for providing a Layer 3 VPN. It creates a separate routing instance (type ‘vprn’) that maintains its own routing table (VRF). The ‘autonomous-system’ parameter within the VPRN configuration is specifically used to define the AS number for BGP peering with the customer edge (CE) router, ensuring proper eBGP session establishment and path attribute handling.

In a VPLS, sites on the same PE communicate via local switching within the VPLS instance. Communication between sites on different PEs requires a pseudowire (PW). The VC-ID (Virtual Circuit Identifier) is a critical label that must match on the SDP bindings at both ends of a pseudowire to form a successful PW connection. A mismatch or missing VC-ID would prevent PW establishment, isolating PEs from each other while local switching remains functional.

A fundamental scaling challenge in BGP/MPLS IP VPNs is the N-squared iBGP peering problem. Without Route Reflectors, every PE router must peer with every other PE router (full mesh) to exchange VPNv4 routes. Route Reflectors allow PEs to peer only with the RRs, which then reflect routes. This creates a hub-and-spoke topology for control plane distribution, dramatically reducing the number of required iBGP sessions from O(N^2) to O(N).

An Epipe is a point-to-point Ethernet service. For a basic working service between two sites, you need: 1) The Epipe service instance itself. 2) Two Service Access Points (SAPs), one at each customer-facing access point. 3) Each SAP must be correctly cross-connected to an SDP binding that targets the far-end PE router. This creates the end-to-end pseudowire for the Layer 2 tunnel. BGP-VPLS is for multipoint services, and a single SAP/spoke-SDP would not complete the point-to-point circuit.

Route Target (RT) extended communities are the fundamental mechanism for controlling VPN route distribution in BGP/MPLS IP VPNs. When a PE exports a VPNv4 route from a VRF, it tags it with one or more export RTs. Remote PE routers import VPNv4 routes into their VRFs based on matching import RTs configured on those VRFs. The value ‘target:64500:100’ is a specific RT used in this import/export process.

IGMP Snooping, when enabled on a VPLS or I-VPLS service, intelligently forwards IP multicast traffic. It listens to IGMP membership reports and creates a forwarding cache, so multicast (and by extension, broadcast-derived) traffic like video streams is only sent to SAPs/SDPs with interested receivers. This significantly reduces unnecessary flood traffic in the VPLS compared to the default behavior of flooding all unknown-unicast, multicast, and broadcast frames.

This is a critical VPLS forwarding concept. Split Horizon is a loop prevention mechanism. A frame received from a spoke-SDP (often used in hierarchical VPLS – H-VPLS to connect to a spoke PE or MTU) is never forwarded to another spoke-SDP within the same service. However, a frame received from a mesh-SDP (connecting to another full-mesh PE) can be forwarded to spoke-SDPs and other mesh-SDPs. Mesh-SDPs are used for the core full-mesh of PWs.

The ‘vrf-target’ command configures the Route Target (RT) policy. The ‘export’ sub-command specifies one or more RT communities that are attached (tagged) to any VPN route that is learned from a CE (via any protocol) and is subsequently advertised as a VPNv4 route to other PE routers via MP-iBGP. This tag tells the receiving PEs which VRFs should import this route.

An IES provides routed internet access. Its key distinction from VPRN is that it interfaces are part of the global routing instance (‘router’ base), not a separate VRF. An IES interface is a logical routed interface (like ‘ies 10’) configured directly under the base router instance. It is not associated with a SAP; instead, it has a logical IP interface (like ‘interface to-subscribers’) that is applied to a SAP defined under the physical port or encapsulation. This connects the Layer 3 interface to the Layer 2 access circuit.

A VPRN (Virtual Private Routed Network) instance is the correct service type for providing a Layer 3 VPN. It creates a separate routing instance (type ‘vprn’) that maintains its own routing table (VRF). The ‘autonomous-system’ parameter within the VPRN configuration is specifically used to define the AS number for BGP peering with the customer edge (CE) router, ensuring proper eBGP session establishment and path attribute handling.0