Provider-Provisioned Layer 3 VPNs: Key Concepts and Benefits

Provider-Provisioned Layer 3 VPNs

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Question

Which two statements are correct about provider-provisioned Layer 3 VPNs? (Choose two.)

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Explanations

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A. B. C. D.

AC

Each routing instance you created on the PE will create a separate table. PE routers and CE routers participate in conventional IP routing, each using a dynamic routing protocol or static routing.

Provider-provisioned Layer 3 VPNs are a type of virtual private network that allows multiple customer sites to communicate with each other over a service provider's network. In this type of VPN, the customer edge (CE) routers at each site connect to the provider edge (PE) routers in the service provider's network. Here are the correct statements about provider-provisioned Layer 3 VPNs:

A. PE routers maintain forwarding tables for each customer VPN: This statement is correct. Each PE router in the service provider's network maintains a separate forwarding table for each customer VPN that is connected to it. The forwarding table contains the routes to all of the remote customer sites that are part of the VPN.

B. PE routers offer a Layer 2 circuit to each CE device: This statement is incorrect. Provider-provisioned Layer 3 VPNs use Layer 3 routing protocols to forward packets between customer sites, not Layer 2 circuits. Layer 2 circuits are typically used in provider-provisioned Layer 2 VPNs, which provide Ethernet connectivity between customer sites.

C. PE routers and CE routers participate in conventional IP routing: This statement is correct. In provider-provisioned Layer 3 VPNs, the PE routers and CE routers participate in conventional IP routing. This means that they use standard IP routing protocols such as OSPF or BGP to exchange routing information and forward packets between customer sites.

D. PE routers exchange VPN traffic through their internal routing protocols: This statement is incorrect. Provider-provisioned Layer 3 VPNs use external routing protocols, such as BGP, to exchange routing information between PE routers. The internal routing protocols used by the PE routers are used to maintain the forwarding tables for each customer VPN, not to exchange traffic between PE routers.