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ZyXEL Confidential
IPv6: Addressing
Milo Liu
SW2
ZyXEL Communications Corp.
3/6/2006
ZyXEL Confidential
Outline
Review IPv4 addressing .
Basic IPv6 address concepts.
IPv6 address space.
Subnetting IPv6 space.
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IPv4 Address
32bit address space.
Subnet defined by a mask.
Unicast host address.
Multicast address.
Broadcast address.
Special address.
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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
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IPv4 Address
Multicast address.
• 1110xxxx + 24bits (223 ~ 240) .xxxxx
Broadcast address.
• 255.255.255.255
Loop-back address.
• 127.0.0.1 (localhost)
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IPv4 Addresses and IPv6 Equivalents
IPv4 Address IPv6 AddressInternet address classes N/AMulticast addresses (224.0.0.0/4) IPv6 multicast addresses (FF00::/8)Broadcast addresses N/AUnspecified address is 0.0.0.0 Unspecified address is ::Loopback address is 127.0.0.1 Loopback address is ::1Public IP addresses Aggregatable global unicast
addressesPrivate IP addresses Site-local addresses (FEC0::/48)APIPA addresses Link-local addresses (FE80::/64)Dotted decimal notation Colon hexadecimal formatSubnet mask or prefix length Prefix length notation only
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IPV6 Address syntax.
• 128bits space. (split by 16bits)
IPv6 Address concept
0010000111011010 0000000011010011 0000000000000000 00101111001110110000001010101010 0000000011111111 1111111000101000 100111000101101021DA:00D3:0000:2F3B:02AA:00FF:FE28:9C5A21DA:D3:0:2F3B:2AA:FF:FE28:9C5A
Prefix (n) Interface ID (128 - n)
128 bits
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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
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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
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Classless Inter-Domain Routing (CIDR)
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IPv6 Addresses Application
Router 1
Subnet 2
Subnet 1
Router 2
Host A
Host B
Site: FEC0::1: 20D:60FF:FECB:6255
Link: FE80::20D:60FF:FECB:6255
Multicast: FF01::1 FF02::1
FF02::1:FFCB:6255
internet
Global: 3000:4D:C00:: 20D:60FF:FECB:6255
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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
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IPv6 Address concept
Unicast address
• Aggregatable global unicast addresses
• Link-local addresses
• Site-local addresses
• Special addresses
• Compatibility addresses
• NSAP addresses
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IPv6 Address concept
IPv6 Address space
• 64bits (subnet section) + 64bits (interface se
ction)
Prefix Interface ID
64 bits 64 bits
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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
TLA ID Interface ID
13 bits 64 bits
SLA ID
24 bits
001 NLA ID
16 bits
Res
8 bits
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Unicast address
Topologies Within Global Addresses
• Public Topology
• Site Topology
• Interface ID
TLA ID Interface ID
64 bits
SLA ID001 NLA ID
16 bits
Res
48 bits
Public Topology Site Topology Interface Identifier
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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
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Unicast address
Link-local addresses
1111 1110 10 Interface ID
10 bits 64 bits
000 . . . 000
54 bits
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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
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Unicast address
Site-local addresses
1111 1110 11 Interface ID
10 bits 64 bits
000 . . . 000
38 bits
Subnet ID
16 bits
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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
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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
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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)
1111 1111 Group ID
8 bits 112 bits
Flags
4 bits
Scope
4 bits
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Scope: 4bits
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Multicast IPv6 Address
Recommended Multicast IPv6 Addresses
• Single IPv6 multicast address maps to a
single Ethernet multicast MAC address
1111 1111 Group ID
8 bits 32 bits
Flags
4 bits
Scope
4 bits 80 bits
000 … 000
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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
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Multicast IPv6 Address
Solicited-Node Address
Interface ID
64 bits
Unicast prefix
64 bits
FF02:
24 bits
:1:FF0:0:0:0
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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
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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
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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
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IPv6 Addresses Application
Router 1
Subnet 2
Subnet 1
Router 2
Host A
Host B
Site: FEC0::1: 20D:60FF:FECB:6255
Link: FE80::20D:60FF:FECB:6255
Multicast: FF01::1 FF02::1
FF02::1:FFCB:6255
internet
Global: 3000:4D:C00:: 20D:60FF:FECB:6255
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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
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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
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IPv6 Interface Identifiers
Extended Unique Identifier (EUI)-64 address
• 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
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Conversion of an IEEE 802 Address to an EUI-64 Address
Host A has the MAC address of 00-0D-60-CB-62-55
• 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.
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00000000 00001101 01100000 11001011 1100010 101010111111111 11111110
0xFF 0xFE
EUI-64 Address
00000000 00001101 01100000
24 bits 24 bits
11001011 1100010 1010101
IEEE-administered company ID Manufacturer-selected extension ID
IEEE 802 Address
00000010 00001101 01100000
64 bits
11111111 11111110 11001011 1100010 1010101
IPv6 Interface Identifier
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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
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IPv6 Multicast Address
33-33-
8 16 24 32
FF...:
Ethernet Multicast Address
Mapping IPv6 Multicast Addresses to Ethernet Addresses
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IPv6 Addresses Application
Router 1
Subnet 2
Subnet 1
Router 2
Host A
Host B
Site: FEC0::1: 20D:60FF:FECB:6255
Link: FE80::20D:60FF:FECB:6255
Multicast: FF01::1 FF02::1
FF02::1:FFCB:6255
internet
Global: 3000:4D:C00:: 20D:60FF:FECB:6255
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Subnetting the IPv6 Address Space
Subnetting for NLA IDs
[16-bit prefix]:00
f r
s
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Subnetting the IPv6 Address Space
Subnetting for SLA IDs
[48-bit prefix]: ::
f
s
r
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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.
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Example
To perform a 3-bit subnetting of the site-local 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).
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Q&A
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Date Subject Lecturer
Introduction to IPv6
IPv6 Addressing
IPv6 Header & Extensions
Neighbor Discovery Protocol
Multicast Listener Discovery
IPv6 Routing
ICMPv6
Address Autoconfigurator
Joe Zhao
Milo Liu
Joe Zhao
Feng Zhou
Billy Bian
Jeffrey Zhou
Feng Zhou
Milo Liu
03/10
03/16
03/23
03/23
03/30
03/30
04/06
04/06
Training course arrangement
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Date Subject Lecturer
Setting Up an IPv6 Test Lab
IPv6 Migration Mechanisms
IPv6 Mobility
Joe Zhou
Milo Liu
04/13
04/20
Training course arrangement