IPV6 Addressing

1. IPv6: Addressing

Milo Liu
SW2
ZyXEL Communications Corp.
3/6/2006
ZyXEL Confidential

2. Outline

Review IPv4 addressing .
Basic IPv6 address concepts.
IPv6 address space.
Subnetting IPv6 space.
ZyXEL Confidential

3. IPv4 Address

32bit address space.
Subnet defined by a mask.
Unicast host address.
Multicast address.
Broadcast address.
Special address.
ZyXEL Confidential

4. IPv4 Address

32 bits address space.
• 11010010 01001001 10001100 00000010
• 210.73.140.2
Subnet mask (Network section and host
section)
• A class (0xxxxxxx) + 24 bit
• B class (10xxxxxxxxxxxxxx) + 16bits
• C class (110xxxxxxxxxxxxxxxxxxxxx) + 8bits
ZyXEL Confidential

5. IPv4 Address

Multicast address.
• 1110xxxx + 24bits (223 ~ 240) .xxxxx
Broadcast address.
• 255.255.255.255
Loop-back address.
• 127.0.0.1 (localhost)
ZyXEL Confidential

6. IPv4 Addresses and IPv6 Equivalents

IPv4 Address
IPv6 Address
Internet address classes
Multicast addresses (224.0.0.0/4)
Broadcast addresses
Unspecified address is 0.0.0.0
Loopback address is 127.0.0.1
Public IP addresses
Private IP addresses
APIPA addresses
Dotted decimal notation
Subnet mask or prefix length
N/A
IPv6 multicast addresses (FF00::/8)
N/A
Unspecified address is ::
Loopback address is ::1
Aggregatable global unicast addresses
Site-local addresses (FEC0::/48)
Link-local addresses (FE80::/64)
Colon hexadecimal format
Prefix length notation only
ZyXEL Confidential

7. IPv6 Address concept

IPV6 Address syntax.
• 128bits space. (split by 16bits)
0010000111011010 0000000011010011
0000000000000000 0010111100111011
0000001010101010 0000000011111111
1111111000101000 1001110001011010
21DA:00D3:0000:2F3B:02AA:00FF:FE28:9C5A
21DA:D3:0:2F3B:2AA:FF:FE28:9C5A
128 bits
Prefix (n)
Interface ID (128 - n)
ZyXEL Confidential

8. IPv6 Address concept

IPv6 address syntax: Compressing Zeros
• FE80:0:0:0:2AA:FF:FE9A:4CA2 becomes
FE80::2AA:FF:FE9A:4CA2
• FF02:0:0:0:0:0:0:2
FF02::2
ZyXEL Confidential

9. IPv6 Address concept

Prefix is part of 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. (Classless
Inter-Domain Routing (CIDR) )
• 21DA:D3::/48 for a route
• 21DA:D3:0:2F3B::/64 for a subnet
ZyXEL Confidential

10. Classless Inter-Domain Routing (CIDR)

ZyXEL Confidential

11. IPv6 Addresses Application

Host B
Router 2
internet
Subnet 2
Router 1
Global: 3000:4D:C00:: 20D:60FF:FECB:6255
Subnet 1
Site: FEC0::1: 20D:60FF:FECB:6255
Link: FE80::20D:60FF:FECB:6255
Host A
Multicast: FF01::1
FF02::1
FF02::1:FFCB:6255
ZyXEL Confidential

12. IPv6 Address concept

Subnet Mask: not required and as prefix of IPv6 address
Type of address
• Unicast
– 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
– Address of a set of interfaces
– One-to-one-of-many delivery to a single interface in the set that is
closest
• No broadcast addresses
ZyXEL Confidential

13. IPv6 Address concept

Unicast address
• Aggregatable global unicast addresses
• Link-local addresses
• Site-local addresses
• Special addresses
• Compatibility addresses
• NSAP addresses
ZyXEL Confidential

14. IPv6 Address concept

IPv6 Address space
• 64bits (subnet section) + 64bits (interface
section)
64 bits
Prefix
64 bits
Interface ID
ZyXEL Confidential

15. Unicast address

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
001 TLA ID
8 bits
Res
24 bits
NLA ID
16 bits
64 bits
SLA ID
Interface ID
ZyXEL Confidential

16. Unicast address

Topologies Within Global Addresses
• Public Topology
• Site Topology
• Interface ID
001 TLA ID
Res
48 bits
Public Topology
NLA ID
SLA ID
Interface ID
16 bits
64 bits
Site Topology
Interface Identifier
ZyXEL Confidential

17. Unicast address

Link-local addresses
• Used between on-link neighbors and for
Neighbor Discovery
• Format Prefix 1111 1110 10
– FE80::/64 prefix
• Used for local link only
– Single subnet, no router
– Address autoconfiguration
– Neighbor Discovery
ZyXEL Confidential

18. Unicast address

Link-local addresses
10 bits
1111 1110 10
54 bits
000 . . . 000
64 bits
Interface ID
ZyXEL Confidential

19. Unicast address

Site-local addresses
• Used between nodes in the same site
• 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
ZyXEL Confidential

20. Unicast address

Site-local addresses
10 bits
38 bits
16 bits
64 bits
1111 1110 11
000 . . . 000
Subnet ID
Interface ID
ZyXEL Confidential

21. Unicast address

Special addresses
• Unspecified address
– 0:0:0:0:0:0:0:0 or ::
• Loopback address
– 0:0:0:0:0:0:0:1 or ::1
ZyXEL Confidential

22. Unicast address

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
– [64-bit prefix]:0:0:WWXX:YYZZ
• 6to4 address
– 2002:WWXX:YYZZ:[SLA ID]:[Interface ID]
• ISATAP address
– Interface ID of ::0:5EFE:w.x.y.z
ZyXEL Confidential

23. Multicast IPv6 Address

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
1111 1111 Flags Scope
112 bits
Group ID
ZyXEL Confidential

24. Scope: 4bits

ZyXEL Confidential

25. Multicast IPv6 Address

Recommended Multicast IPv6 Addresses
• Single IPv6 multicast address maps to a
single Ethernet multicast MAC address
8 bits
4 bits
4 bits
1111 1111 Flags Scope
80 bits
32 bits
000 … 000
Group ID
ZyXEL Confidential

26. Multicast IPv6 Address

Solicited-Node Address
• Acts as a pseudo-unicast address for very
efficient address resolution
• For FE80::2AA:FF:FE28:9C5A, the
corresponding solicited-node address is
FF02::1:FF28:9C5A
ZyXEL Confidential

27. Multicast IPv6 Address

Solicited-Node Address
64 bits
64 bits
Unicast prefix
Interface ID
24 bits
FF02:
0:0:0:0
:1:FF
ZyXEL Confidential

28. Anycast IPv6 Address

An anycast address is an address that is
assigned to a set of interfaces that typically
belong to different nodes.
A packet sent to an anycast address is
delivered to the closest interface.
Anycast addresses can be used only by a router,
not a host, and anycast addresses must not be
used as the source address of an IPv6 packet.
Subnet router anycast address
ZyXEL Confidential

29. IPv6 Addresses Application

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)
• Listen 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
ZyXEL Confidential

30. IPv6 Addresses Application

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)
• Listen 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
ZyXEL Confidential

31. IPv6 Addresses Application

Host B
Router 2
internet
Subnet 2
Router 1
Global: 3000:4D:C00:: 20D:60FF:FECB:6255
Subnet 1
Site: FEC0::1: 20D:60FF:FECB:6255
Link: FE80::20D:60FF:FECB:6255
Host A
Multicast: FF01::1
FF02::1
FF02::1:FFCB:6255
ZyXEL Confidential

32. IPv6 Interface Identifiers

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
ZyXEL Confidential

33. IEEE EUI-64 Addresses

Extended Unique Identifier
Company ID
Extension ID
24 bits
ccccccug cccccccc cccccccc
IEEE-administered company ID
40 bits
xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
Manufacturer-selected extension ID
ZyXEL Confidential

34. IPv6 Interface Identifiers

Extended Unique Identifier (EUI)-64
address
• Extended Unique Identifier
• Company ID
• Extension ID
24 bits
ccccccug cccccccc cccccccc
IEEE-administered company ID
40 bits
xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
Manufacturer-selected extension ID
ZyXEL Confidential

35. Conversion of an IEEE 802 Address to an EUI-64 Address

Host A has the MAC address of 00-0D-60-CB-6255
• 1. Convert to EUI-64 format
– 00-0D-60-FF-FE-CB-62-55
• 2. Complement the U/L bit
– The first byte in binary form is 00000000. When the seventh
bit is complemented, it becomes 00000010 (0x02).
– Result is 02-0D-60-FF-FE-CB-62-55
• 3. Convert to colon hexadecimal notation
– 20D:60FF:FECB:6255
Link-local address for node with the MAC
address of 00-0D-60-CB-62-55 is FE80::
20D:60FF:FECB:6255.
ZyXEL Confidential

36.

IEEE-administered company ID
24 bits
00000000 00001101 01100000
Manufacturer-selected extension ID
24 bits
11001011 1100010 1010101
IEEE 802 Address
EUI-64 Address
00000000 00001101 01100000 11111111 11111110
0xFF
00000010 00001101 01100000
11001011 1100010 1010101
0xFE
11111111 11111110 11001011 1100010 1010101
IPv6 Interface Identifier
64 bits
ZyXEL Confidential

37. 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
ZyXEL Confidential

38. Mapping IPv6 Multicast Addresses to Ethernet Addresses

IPv6
Multicast Address
8
16
24
32
FF...:
Ethernet
Multicast Address
33-33ZyXEL Confidential

39. IPv6 Addresses Application

Host B
Router 2
internet
Subnet 2
Router 1
Global: 3000:4D:C00:: 20D:60FF:FECB:6255
Subnet 1
Site: FEC0::1: 20D:60FF:FECB:6255
Link: FE80::20D:60FF:FECB:6255
Host A
Multicast: FF01::1
FF02::1
FF02::1:FFCB:6255
ZyXEL Confidential

40. Subnetting the IPv6 Address Space

Subnetting for NLA IDs
f
r
[16-bit prefix]:00
s
ZyXEL Confidential

41. Subnetting the IPv6 Address Space

Subnetting for SLA IDs
f
r
::
[48-bit prefix]:
s
ZyXEL Confidential

42. Expression

Based on s (the number of bits chosen for subnetting), m (the
prefix length of the network prefix being subnetted), and F
(the hexadecimal value of the subnet being subnetted),
calculate the following:
f = m - 48
f is the number of bits within the subnet ID that are already fixed.
n = 2s
n is the number of network prefixes that are obtained.
i = 216-(f+s)
i is the incremental value between each successive subnet ID
expressed in hexadecimal form.
l = 48 + f + s
l is the prefix length of the new subnetted network prefixes.
ZyXEL Confidential

43. Example

To perform a 3-bit subnetting of the sitelocal network prefix FEC0:0:0:C000::/51,
we first calculate the values of the
number of prefixes, the increment, and
the new prefix length. Our starting
values are F = 0xC000, s = 3, and f = 51 48 = 3. The number of prefixes is 8 (n =
23). The increment is 0x400 (i = 216-(3+3)
= 1024 = 0x400). The new prefix length is
54 (l = 48 + 3 + 3).
ZyXEL Confidential

44. Q&A

Q&A
ZyXEL Confidential

45. Training course arrangement

Date
Subject
03/10
Introduction to IPv6
03/16
IPv6 Addressing
03/23
03/23
IPv6 Header & Extensions
ICMPv6
Lecturer
Joe Zhao
Milo Liu
Joe Zhao
Feng Zhou
03/30
Neighbor Discovery Protocol
Billy Bian
03/30
Multicast Listener Discovery
Jeffrey Zhou
04/06
Address Autoconfigurator
04/06
IPv6 Routing
Feng Zhou
Milo Liu
ZyXEL Confidential

46. Training course arrangement

Date
04/13
04/20
Subject
Lecturer
IPv6 Migration Mechanisms
Joe Zhou
IPv6 Mobility
Milo Liu
Setting Up an IPv6 Test Lab
ZyXEL Confidential