Your company is researching a new application that runs over IPv6, but part of it must still have
IPv4 support. Your company uses a traditional IPv4 network. Your plan is not to run IPv6 over the
whole network, but to segment parts of the network or even to operate simultaneously with IPv6
and IPv4. You must make a brief presentation about IPv6 technology to the board of technical
directors. Which three of these items could be part of your presentation? (Choose three.)
A.
Tunnel IPv6 over IPv4 to connect far-end IPv6 networks.
B.
Explain why configuring IPv4 and IPv6 at the same time over the same LAN interface is not
possible.
C.
Explain why configuring IPv4 and IPv6 at the same time over the same LAN interface is
possible.
D.
What is the meaning of EUI-64 and how does it work?
E.
Tunnel IPv4 over IPv6 to connect far-end IPv4 networks.
Explanation:
An interface ID is used to identify interfaces on a link. The interface ID must be unique to the link.
It may also be unique over a broader scope. In many cases, an interface ID will be the same as or
based on the link-layer address of an interface. Interface IDs used in aggregatable global unicast
and other IPv6 address types must be 64 bits long and constructed in the modified EUI-64 format.Interface IDs are constructed in the modified EUI-64 format in one of the following ways:
For all IEEE 802 interface types (for example, Ethernet, and FDDI interfaces), the first three octets
(24 bits) are taken from the Organizationally Unique Identifier (OUI) of the 48-bit link-layer address
(the Media Access Control [MAC] address) of the interface, the fourth and fifth octets (16 bits) are
a fixed hexadecimal value of FFFE, and the last three octets (24 bits) are taken from the last three
octets of the MAC address. The construction of the interface ID is completed by setting the
Universal/Local (U/L) bit the seventh bit of the first octet a value of 0 or 1. A value of 0 indicates a
locally administered identifier; a value of 1 indicates a globally
unique IPv6 interface identifier.
For other interface types (for example, serial, loopback, ATM, Frame Relay, and tunnel interface
types except tunnel interfaces used with IPv6 overlay tunnels), the interface ID is constructed in
the same way as the interface ID for IEEE 802 interface types; however, the first MAC address
from the pool of MAC addresses in the router is used to construct the identifier (because the
interface does not have a MAC address).
For tunnel interface types that are used with IPv6 overlay tunnels, the interface ID is the IPv4
address assigned to the tunnel interface with all zeros in the high-order 32 bits of the identifier.
An IPv4-compatible IPv6 address is an IPv6 unicast address that has zeros in the high-order 96
bits of the address and an IPv4 address in the low-order 32 bits of the address. The format of an
IPv4- compatible IPv6 address is 0:0:0:0:0:0:A.B.C.D or ::A.B.C.D. The entire 128-bit IPv4-
compatible IPv6 address is used as the IPv6 address of a node and the IPv4 address embedded
in the low-order 32 bits is used as the IPv4 address of the node. IPv4-compatible IPv6 addresses
are assigned to nodes that support both the IPv4 and IPv6 protocol stacks and are used in
automatic tunnels.