Refer to the exhibit. The service provider ACME wants to offer IPv6 services to their subscribers. However, their access and aggregation devices are IPv4-only and not capable of IPv6 transport without

Question

Exhibit

Options

• ADS-Lite
• BDMVPN
• CAFT64
• D6RD
• ESLAAC

• A
  19% (6)
• B
  65% (20)
• C
  10% (3)
• E
  6% (2)

Explanation

The scenario requires extending IPv6 connectivity from the service provider edge to the CPE across an IPv4-only access/aggregation middle network. Two technologies accomplish this by tunneling IPv6-in-IPv4:

• 6RD (IPv6 Rapid Deployment) [D]: Designed precisely for this use case. The CPE encapsulates IPv6 traffic inside IPv4 packets, tunneling it to a 6RD Border Relay at the SP edge. It requires only a software upgrade on CPE and edge equipment and works transparently over IPv4-only access infrastructure.

• DMVPN (Dynamic Multipoint VPN) [B]: Creates mGRE-based overlay tunnels that can carry IPv6 traffic over an IPv4 underlay. With software upgrades on CPE and edge, DMVPN can extend IPv6 services end-to-end over the IPv4 access network.

The other options are eliminated for these reasons:

• DS-Lite [A]: Tunnels IPv4-in-IPv6 - the opposite direction (used when access is IPv6 but users need IPv4).
• AFT64 [C]: An address family translation/NAT64 mechanism, not a tunneling technology for IPv6-over-IPv4 transport.
• SLAAC [E]: A stateless IPv6 address autoconfiguration protocol, not a transition/tunneling technology.

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