There are two rules defining how an IPv6 address can be compressed. The first rule
states that leading zeros in a hextet can be eliminated. The second rule states that a single :: can
be used to represent one or more contiguous all zero hextets. There can be one and only one :: in
an IPv6 address.
19. What is the prefix associated with the IPv6 address 2001:DB8:D15:EA:CC44::1/64?
The address ::1 is an IPv6 loopback address. Using the command ping ::1 tests the
internal IP stack to ensure that it is configured and functioning correctly. It does not test
reachability to any external device, nor does it confirm that IPv6 addresses are properly
configured on the host.
23. What is the interface ID of the IPv6 address 2001:DB8::1000:A9CD:47FF:FE57:FE94/64?
The IPv6 address 2001:0db8:0000:abcd:0000:0000:0000:0001 in its most
compressed format would be 2001:db8:0:abcd::1. The one leading zero in the second hextet can
be removed. The first hextet of zeros would be compressed to a single zero. The three
consecutive hextets of zeros can be compressed to a double colon ::. The three leading zeros in
the last hextet can be removed. The double colon :: can only be used once in an address.
28. What is the minimum configuration for a router interface that is enabled for IPv6?
A. To have a self-generated loopback address
B. To have both a link-local and a global unicast IPv6 address
With IPv6, a router interface typically has more than one IPv6 address. The router
will at least have a link-local address that can be automatically generated, but the router
commonly has an global unicast address also configured.
29. At a minimum, which address is required on IPv6-enabled interfaces?
There are three elements that make up an IPv6 global unicast address. A global
routing prefix which is provided by an ISP, a subnet ID which is determined by the organization,
and an interface ID which uniquely identifies the interface interface of a host.
31. Your organization is issued the IPv6 prefix of 2001:db8:130f::/48 by your service provider. With
this prefix, how many bits are available for your organization to create /64 subnetworks if
interface ID bits are not borrowed?
The global routing prefix that is assigned to the organization has 48 bits. The next
16 bits are used for the subnet ID. This makes up the first 64 bits of the address, which is
typically the network portion of the address. The remaining 64 bits of the 128-bit IPv6 address
are for the interface ID (or host) portion of the address.
32. Which type of IPv6 address is not routable and used only for communication on a single subnet?