Implementing Mpls L3Vpns - References; Mpls L3Vpn Benefits; Major Components Of Mpls L3Vpn-Details; Virtual Routing And Forwarding Tables - Cisco NCS 540 Series Configuration Manual

Implementing MPLS L3VPNs - References

Implementing MPLS L3VPNs - References

MPLS L3VPN Benefits

MPLS L3VPN provides the following benefits:
• Service providers can deploy scalable VPNs and deliver value-added services.
• Connectionless service guarantees that no prior action is necessary to establish communication between
• Centralized Service: Building VPNs in Layer 3 permits delivery of targeted services to a group of users
• Scalability: Create scalable VPNs using connection-oriented and point-to-point overlays.
• Security: Security is provided at the edge of a provider network (ensuring that packets received from a
• Integrated Quality of Service (QoS) support: QoS provides the ability to address predictable performance
• Straightforward Migration: Service providers can deploy VPN services using a straightforward migration
• Migration for the end customer is simplified. There is no requirement to support MPLS on the CE router
Major Components of MPLS L3VPN Details

Virtual Routing and Forwarding Tables

Each VPN is associated with one or more VPN routing and forwarding (VRF) instances. A VRF defines the
VPN membership of a customer site attached to a PE router. A VRF consists of the following components:
• An IP version 4 (IPv4) unicast routing table
• A derived FIB table
• A set of interfaces that use the forwarding table
• A set of rules and routing protocol parameters that control the information that is included in the routing
These components are collectively called a VRF instance.
A one-to-one relationship does not necessarily exist between customer sites and VPNs. A site can be a member
of multiple VPNs. However, a site can associate with only one VRF. A VRF contains all the routes available
to the site from the VPNs of which it is a member.
Packet forwarding information is stored in the IP routing table and the FIB table for each VRF. A separate
set of routing and FIB tables is maintained for each VRF. These tables prevent information from being
L3VPN Configuration Guide for Cisco NCS 540 Series Routers, IOS XR Release 6.3.x
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hosts.
represented by a VPN.
customer are placed on the correct VPN) and in the backbone.
and policy implementation and support for multiple levels of service in an MPLS VPN.
path.
and no modifications are required for a customer intranet.
table
MPLS L3VPN Overview