Module 12: IPv6 Addressing

• Dual stack

• Tunneling

• Translation

Three categories of IPv6 migration techniques

Dual stack

The devices run both IPv4 and IPv6 protocol stacks simultaneously.

Tunneling

A method of transporting an IPv6 packet over an IPv4 network. The IPv6 packet is encapsulated inside an IPv4 packet.

Translation

Network Address Translation 64 (NAT64) allows IPv6-enabled devices to communicate with IPv4-enabled devices using a translation technique similar to NAT for IPv4.

IPv6 addresses

• are 128 bits in length and written in hexadecimal.

• are not case-sensitive and can be written in either lowercase or

  uppercase.

• The preferred format for writing an IPv6 address is x:x:x:x:x:x:x:x, with each “x”

  consisting of four hexadecimal values.

hextet

is the unofficial term used to refer to a segment of 16 bits, or four

Omit Leading Zero

The first rule to help reduce the notation of IPv6 addresses is to _______________.

double colon (::)

• can replace any single, contiguous string of one or more 16-bit hextets consisting of all zeros.

• can only be used once within an address, otherwise there would be more than one possible resulting address

• Unicast

• Multicast

• Anycast

three broad categories of IPv6 addresses:

Unicast

uniquely identifies an interface on an IPv6-enabled device.

Multicast

is used to send a single IPv6 packet to multiple destinations.

Anycast

This is any IPv6 unicast address that can be assigned to multiple devices.

Prefix length

is represented in slash notation and is used to indicate the network portion of an IPv6 address.

0 to 128

The IPv6 prefix length can range from __________.

/64

The recommended IPv6 prefix length for LANs and most other types of networks

• Global Unicast Address (GUA)

• Link-local Address (LLA)

(2) Types of IPv6 Unicast Addresses

Global Unicast Address (GUA)

This is similar to a public IPv4 address. These are globally unique, internet-routable addresses.

Link-local Address (LLA)

• Required for every IPv6-enabled device and used to communicate with other devices on the same local link.

• These are not routable and are confined to a single link.

Unique Local Address

• are used for local addressing within a site or between a limited number of sites

• can be used for devices that will never need to access

  another network.

• not globally routed or translated to a global IPv6

  address.

Global Routing Prefix

• is the prefix, or network, portion of the address that is assigned by the provider, such as an ISP, to a customer or site

• will vary depending on ISP policies

Subnet ID

• is the area between the Global Routing Prefix and the Interface ID.

• is used by an organization to identify subnets within its site.

Interface ID

The IPv6 interface ID is equivalent to the host portion of an IPv4 address.

Router Solicitation (RS)

messages are sent by host devices to discover IPv6 routers

Router Advertisement (RA)

messages are sent by routers to inform hosts on how to obtain an IPv6 GUA and provide useful network information

SLAAC

allows a device to configure a GUA without the services of DHCPv6.

EUI-64 Process

• A 16 bit value of fffe (in hexadecimal) is inserted into the middle of the 48-bit Ethernet MAC address of the client

• The 7th bit of the client MAC address is reversed from binary 0 to 1.

Randomly Generated Interface IDs

a device may use a randomly generated interface ID instead of using the MAC address and the EUI-64 process.

Duplicate Address Detection (DAD)

To ensure the uniqueness of any IPv6 unicast address, the client may use a process known as ______________.

• Well-Known multicast addresses

• Solicited node multicast addresses

There are two types of IPv6 multicast addresses:

Well-known IPv6 multicast addresses

are assigned and are reserved for predefined groups of devices.

• ff02::1 All-nodes multicast group

• ff02::2 All-routers multicast group

There are two common IPv6 Assigned multicast groups:

ff02::1 All-nodes multicast group

This is a multicast group that all IPv6-enabled devices join.

A packet sent to this group is received and processed by all IPv6 interfaces on the link or network.

ff02::2 All-routers multicast group

This is a multicast group that all IPv6 routers join. A router becomes a member of this group when it is enabled as an IPv6 router with the ipv6 unicast-routing global configuration command.

Solicited-Node IPv6 Multicast

• is similar to the all-nodes multicast address.

• is mapped to a special Ethernet multicast address.

subnet ID

is the area between the Global Routing Prefix and the interface ID.