MPLS Layer 3 VPNs: Functions and Benefits

Functions of MPLS Layer 3 VPNs

Question

What are two functions of MPLS Layer 3 VPNs? (Choose two.)

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Explanations

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CD.

MPLS (Multiprotocol Label Switching) Layer 3 VPNs (Virtual Private Networks) are a technology used to provide secure and scalable communication between geographically dispersed sites of an organization over a service provider's MPLS backbone.

The functions of MPLS Layer 3 VPNs include:

  1. Encapsulation of customer traffic in a VPN label: In MPLS Layer 3 VPNs, customer traffic is encapsulated in a VPN label when it is forwarded through the MPLS network. This VPN label is used to distinguish between different VPNs and to ensure that traffic for one VPN does not mix with traffic for another VPN. Each VPN is assigned a unique VPN label, which is used by the MPLS network to forward traffic to the appropriate destination.

  2. Signaling of customer VPNv4 routes between PE nodes using BGP: Border Gateway Protocol (BGP) is used to exchange customer VPNv4 routes between Provider Edge (PE) nodes in an MPLS Layer 3 VPN. Each PE node maintains a Virtual Routing and Forwarding (VRF) table for each VPN, which contains the routes for that VPN. BGP is used to distribute these routes between the PE nodes, so that each node has a complete view of the routes for all VPNs.

In summary, MPLS Layer 3 VPNs provide secure and scalable connectivity between geographically dispersed sites of an organization by encapsulating customer traffic in a VPN label and using BGP to signal customer VPNv4 routes between PE nodes.