9-3 - Basic Solutions to Deploy IPv6 over MPLS VPN Environments

Question 1

Basic solutions for deploying IPv6 over MPLS VPN environments include the following:

Answer 1

• Deploy IPv6 by using tunnels on the CE routers
• Deploy IPv6 over a Layer 2 MPLS VPN

Question 2

IPv6 tunnels that you configure on a CE have these characteristics:

Answer 2

• The CE routers are IPv6-aware (dual stack).
• A mesh of IPv6-over-IPv4 tunnels connects CE to CE.
• Overhead includes the IPv4 header and MPLS header.
• MPLS and VPN support native IPv4 and IPv6 tunnels.

Question 3

T/F: Communication between the remote IPv6 domains uses standard tunneling mechanisms that run IPv6 over IPv4 tunnels as the mechanism for MPLS VPN support for native IPv4 tunnels.

Answer 3

True

Question 4

T/F: You must upgrade the CE routers to dual stack and configure them with manually configured tunnels or 6to4 tunnels.

Answer 4

True

Question 5

Pros of IPv6-in-IPv4 Tunnels on CE Routers

Answer 5

This approach has no impact on the operation or infrastructure of MPLS and requires no changes to either the P routers in the core or the PE routers that connect to customers.

Question 6

Cons of IPv6-in-IPv4 Tunnels on CE Routers

Answer 6

• As the number of tunnel partners grows, the number of tunnels in an any-to-any mesh increases quickly, making management of the tunnels error-prone and expensive.
• Delegating a global IPv6 prefix for an ISP is also difficult, because the ISP does not furnish the IPv6 connectivity; it merely provides transport.

Question 7

IPv6 with a Layer 2 MPLS VPN has these characteristics:

Answer 7

• IPv6 runs over pseudowires or in virtual bridge domains.
• Edge MPLS routers must support a Layer 2 MPLS VPN.
• A mesh of virtual circuits connects PE to PE.
• The PE routers are regular IPv4 routers that aggregate customer IPv6 routers.

Question 8

Pros of Layer 2 MPLS VPNs to Support IPv6

Answer 8

• Simple solution for service providers with ATM or Ethernet links to CE routers and circuit over MPLS capability.
• Fully transparent IPv6 communication, from the provider perspective.
• No necessary reconfiguration of the MPLS core.

Question 9

Cons of Layer 2 MPLS VPNs to Support IPv6

Answer 9

• Equivalent to Layer 2 VPN complexity.
• You must upgrade PE routers that connect to customers to a Layer 2 MPLS VPN.
• The difficulty of delegating a global IPv6 prefix for an ISP.

Question 10

Which two of the following are basic solutions for deploying IPv6 over MPLS VPN environments? (Choose two.)

A. Layer 2 MPLS VPNs
B. Layer 3 MPLS on IPv4 networks
C. IPv4 tunnels configured on the PE
D. IPv6 tunnels configured on the P
E. IPv6 tunnels configured on the CE

Answer 10

A,E