9-6 - Use GRE for IPv6 Connectivity in MPLS VPN Environments

Question 1

Describe PE-to-PE Tunneling

Answer 1

traffic that is destined to multiple customer networks is multiplexed through a single GRE tunnel between PEs

Question 2

Describe P-to-PE Tunneling

Answer 2

traffic that is destined to the other side of the non-MPLS network transmits through a single GRE tunnel

Question 3

Describe P-to-P Tunneling

Answer 3

MPLS traffic that is destined to the other side of the non-MPLS network transmits through a single GRE tunnel.

Question 4

Describe 6PE and 6VPE over GRE.

Answer 4

• The 6PE and 6VPE over GRE feature allows you to use IPv4 GRE tunnels to provide IPv6 VPN over MPLS functionality to reach the destination IPv6 prefixes via the BGP next hop through MPLS- and IPv6-unaware core.
• The ingress PE device uses IPv4 Generic Routing Encapsulation (GRE) tunnels combined with 6PE or 6VPE over MPLS to tunnel IPv6 VPN packets over the backbone toward the egress PE device that you identify as the BGP next hop.
• The PE devices establish Multiprotocol Internal Border Gateway Protocol (MP-IBGP) sessions and MPLS LDP sessions just as in the case of 6PE and 6VPE.
• The difference here is that these sessions establish over GRE tunnels, and so the PEs are just one IGP hop away.

Question 5

Which of the following statements about GRE tunnels for IPv6 is true?

A. PE-to-PE tunneling configuration provides a scalable way to connect multiple customer networks across a non-MPLS network.
B. L3VPN over GRE basically means encapsulating GRE traffic in an L3VPN header.
C. With PE-to-PE tunneling, traffic that is destined to multiple customer networks transmits through multiple GRE tunnels.
D. P-to-PE tunneling configuration provides a way to connect a PE device (P1) to an MPLS segment (PE2) across an MPLS network.

Answer 5

A