1. Lesson 3
IPv6 Addressing

2. Lesson Objectives IPv6 address space IPv6 address syntax
Unicast IPv6 addresses
Multicast IPv6 addresses
Anycast IPv6 addresses
IPv6 interface identifiers
IPv4 addresses and IPv6 equivalents

3. The IPv6 Address Space 128-bit address space
2128 possible addresses
340,282,366,920,938,463,463,374,607,431,768,211,456 addresses (3.4 x 1038)
128 bits were chosen to allow multiple levels of hierarchy and flexibility in designing hierarchical addressing and routing
Typical unicast IPv6 address:
64 bits for subnet ID, 64 bits for interface ID

4. Current Allocation Format Fraction of Allocation Prefix address space
Reserved /256
NSAP Allocation /128
Aggregatable Global Unicast 001 1/8
Link-Local Unicast /1024
Site-Local Unicast /1024
Multicast /256

5. IPv6 Address Syntax IPv6 address in binary form:
Divided along 16-bit boundaries:
Each 16-bit block is converted to hexadecimal and delimited with colons:
21DA:00D3:0000:2F3B:02AA:00FF:FE28:9C5A
Suppress leading zeros within each 16-bit block:
21DA:D3:0:2F3B:2AA:FF:FE28:9C5A

6. Compressing Zeros Some IPv6 addresses contain long sequences of zeros
A single contiguous sequence of 16-bit blocks set to 0 can be compressed to “::” (double-colon)
Example:
FE80:0:0:0:2AA:FF:FE9A:4CA2 becomes FE80::2AA:FF:FE9A:4CA2
FF02:0:0:0:0:0:0:2 becomes FF02::2
Cannot use zero compression to include part of a 16-bit block
FF02:30:0:0:0:0:0:5 does not become FF02:3::5.

7. IPv6 Prefixes
Prefix is the part of the address where the bits have fixed values or are the bits of a route or subnet identifier
IPv6 subnets or routes always uses address/prefix-length notation
CIDR notation
Examples:
21DA:D3::/48 for a route
21DA:D3:0:2F3B::/64 for a subnet
No more dotted decimal subnet masks

8. Types of IPv6 Addresses Unicast Multicast Anycast
Address of a single interface
One-to-one delivery to single interface
Multicast
Address of a set of interfaces
One-to-many delivery to all interfaces in the set
Anycast
One-to-one-of-many delivery to a single interface in the set that is closest
No more broadcast addresses

9. Unicast IPv6 Addresses Aggregatable global unicast addresses
Link-local addresses
Site-local addresses
Special addresses
Compatibility addresses
NSAP addresses

10. Aggregatable Global Unicast Addresses
Top-Level Aggregation ID (TLA ID)
Next-Level Aggregation ID (NLA ID)
Site-Level Aggregation ID (SLA ID)
Interface ID
13 bits
8 bits
24 bits
16 bits
64 bits
001
TLA ID
Res
NLA ID
SLA ID
Interface ID

11. Topologies Within Global Addresses
Public Topology
Site Topology
Interface ID
001
TLA ID
Res
NLA ID
SLA ID
Interface ID
48 bits
16 bits
64 bits
Public Topology
Site Topology
Interface Identifier

12. Local-Use Unicast Addresses
Link-local addresses
Used between on-link neighbors and for Neighbor Discovery
Site-local addresses
Used between nodes in the same site

13. Link-Local Addresses Format Prefix 1111 1110 10
FE80::/64 prefix
Used for local link only
Single subnet, no router
Address autoconfiguration
Neighbor Discovery
10 bits
54 bits
64 bits
Interface ID

14. Site-Local Addresses Format Prefix 1111 1110 11
FEC0::/48 prefix for site
Used for local site only
Replacement for IPv4 private addresses
Intranets not connected to the Internet
Routers do not forward site-local traffic outside the site
10 bits
38 bits
16 bits
64 bits
Subnet ID
Interface ID

15. Special IPv6 Addresses Unspecified address Loopback address
0:0:0:0:0:0:0:0 or ::
Loopback address
0:0:0:0:0:0:0:1 or ::1

16. Compatibility Addresses
IPv4-compatible address
0:0:0:0:0:0:w.x.y.z or ::w.x.y.z
IPv4-mapped address
0:0:0:0:0:FFFF:w.x.y.z or ::FFFF:w.x.y.z
6over4 address
Interface ID of ::WWXX:YYZZ
6to4 address
Prefix of 2002:WWXX:YYZZ::/48
ISATAP address
Interface ID of ::0:5EFE:w.x.y.z

17. NSAP Addresses
7 bits
121 bits
NSAP-mapped address

18. Multicast IPv6 Addresses
Flags
Scope
Defined multicast addresses
All-Nodes addresses
FF01::1 (Node Local), FF02::1 (Link Local)
All-Routers addresses
FF01::2 (Node Local), FF02::2 (Link Local), FF05::2 (Site Local)
8 bits
4 bits
4 bits
112 bits
Flags
Scope
Group ID

19. Recommended Multicast IPv6 Addresses
Only 32 bits are used to indicate the Group ID
Single IPv6 multicast address maps to a single Ethernet multicast MAC address
8 bits
4 bits
4 bits
80 bits
32 bits
Flags
Scope
000 … 000
Group ID

20. Solicited-Node Address
64 bits
64 bits
Unicast prefix
Interface ID
24 bits
FF02:
0:0:0:0
:1:FF
Example:
For FE80::2AA:FF:FE28:9C5A, the corresponding solicited-node address is FF02::1:FF28:9C5A
Acts as a pseudo-unicast address for very efficient address resolution

21. Anycast IPv6 Addresses Not associated with any prefix
Summary and host routes are used to locate nearest anycast group member
Subnet router anycast address:
n bits
128 - n bits
Subnet Prefix

22. IPv6 Addresses for a Host
Unicast addresses:
A link-local address for each interface
Unicast addresses for each interface (site-local or global addresses)
A loopback address (::1)
Multicast addresses:
The node-local scope all-nodes multicast address (FF01::1)
The link-local scope all-nodes multicast address (FF02::1)
The solicited-node address for each unicast address
The multicast addresses of joined groups

23. IPv6 Addresses for a Router
Unicast addresses:
A link-local address for each interface
Unicast addresses for each interface
Loopback address (::1)
Anycast addresses
Subnet-router anycast address
Additional anycast addresses (optional)
Multicast addresses:
The node-local scope all-nodes multicast address (FF01::1)
The node-local scope all-routers multicast address (FF01::2)
The link-local scope all-nodes multicast address (FF02::1)
The link-local scope all-routers multicast address (FF02::2)
The site-local scope all-routers multicast address (FF05::2)
The solicited-node address for each unicast address
The multicast addresses of joined groups

24. Subnetting the IPv6 Address Space
Subdividing by using high-order bits that do not already have fixed values to create subnetted network prefixes
Two-step process:
1. Determine the number of bits to be used for the subnetting
2. Enumerate the new subnetted network prefixes

25. [16-bit prefix]:00 :: Subnetting for NLA IDs Hexadecimal method

26. [48-bit prefix]: :: Subnetting for SLA IDs Hexadecimal method

27. IPv6 Interface Identifiers
The last 64 bits of unicast IPv6 addresses
Interface identifier based on:
Extended Unique Identifier (EUI)-64 address
Either assigned to a network adapter card or derived from IEEE 802 addresses
Temporarily assigned, randomly generated value that changes over time
A value assigned by a stateful address configuration protocol
A value assigned during a Point-to-Point Protocol connection establishment
A manually configured value

28. IEEE 802 Addresses Company ID Extension ID U/L bit (u) U/G bit (g)
Universally (=0)/Locally (=1) Administered
U/G bit (g)
Unicast (=0)/Group (=1) Address
24 bits
24 bits
ccccccug cccccccc cccccccc
xxxxxxxx xxxxxxxx xxxxxxxx
IEEE-administered company ID
Manufacturer-selected extension ID

29. IEEE EUI-64 Addresses Extended Unique Identifier Company ID
Extension ID
ccccccug cccccccc cccccccc
24 bits
40 bits
xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
IEEE-administered company ID
Manufacturer-selected extension ID

30. Conversion of an IEEE 802 Address to an EUI-64 Address
IEEE-administered company ID
Manufacturer-selected extension ID
24 bits
24 bits
ccccccug cccccccc cccccccc
xxxxxxxx xxxxxxxx xxxxxxxx
IEEE 802 Address
ccccccug cccccccc cccccccc
xxxxxxxx xxxxxxxx xxxxxxxx
EUI-64 Address
0xFF
0xFE

31. Conversion of an EUI-64 Address to an IPv6 Interface ID
ccccccug cccccccc cccccccc
xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
Complement the universally/locally administered (U/L) bit
ccccccUg cccccccc cccccccc
xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
IPv6 Interface Identifier

32. Conversion of an IEEE 802 Address to an IPv6 Interface ID
IEEE-administered company ID
Manufacturer-selected extension ID
24 bits
24 bits
cccccc00 cccccccc cccccccc
xxxxxxxx xxxxxxxx xxxxxxxx
IEEE 802 Address
EUI-64 Address
cccccc00 cccccccc cccccccc
xxxxxxxx xxxxxxxx xxxxxxxx
0xFF
0xFE
cccccc10 cccccccc cccccccc
xxxxxxxx xxxxxxxx xxxxxxxx
IPv6 Interface Identifier
64 bits

33. IEEE 802 Address Conversion Example
Host A has the MAC address of 00-AA-00-3F-2A-1C
1. Convert to EUI-64 format
00-AA-00-FF-FE-3F-2A-1C
2. Complement the U/L bit
The first byte in binary form is When the seventh bit is complemented, it becomes (0x02).
Result is 02-AA-00-FF-FE-3F-2A-1C
3. Convert to colon hexadecimal notation
2AA:FF:FE3F:2A1C
Link-local address for node with the MAC address of 00-AA-00-3F-2A-1C is FE80::2AA:FF:FE3F:2A1C.

34. Temporary Address Interface Identifiers
Random IPv6 interface identifier
Prevent identification of traffic regardless of the prefix
Initial value based on random number
Future values based on MD5 hash of history value and EUI-64-based interface identifier
Result is a temporary address
Generated from public address prefixes using stateless address autoconfiguration
Changes over time

35. Mapping IPv6 Multicast Addresses to Ethernet Addresses8 16 24 32
FF...:
Ethernet
Multicast Address
33-33-

36. IPv4 Addresses and IPv6 Equivalents
IPv4 Address IPv6 Address
Internet address classes N/A
Multicast addresses ( /4) IPv6 multicast addresses (FF00::/8)
Broadcast addresses N/A
Unspecified address is Unspecified address is ::
Loopback address is Loopback address is ::1
Public IP addresses Aggregatable global unicast addresses
Private IP addresses Site-local addresses (FEC0::/48)
APIPA addresses Link-local addresses (FE80::/64)
Dotted decimal notation Colon hexadecimal format
Subnet mask or prefix length Prefix length notation only

37. Review IPv6 address space IPv6 address syntax Unicast IPv6 addresses
Multicast IPv6 addresses
Anycast IPv6 addresses
IPv6 interface identifiers
IPv4 addresses and IPv6 equivalents