ZyXEL Confidential Address Autoconfiguration Feng Zou SW2 ZyXEL Communications Corp. 04/11/2006
Jan 18, 2016
ZyXEL Confidential
Address Autoconfiguration
Feng Zou
SW2
ZyXEL Communications Corp.
04/11/2006
ZyXEL Confidential
Outline
Why We Need Address Autoconfiguration?
IPv6 Address Structure Review
How to Autoconfiguration?
Autoconfiguration Process
Autoconfigured Address States
Types of Autoconfiguration
Q&A
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Why We Need Address Autoconfiguration?
The size of an address in IPv6 is 128 bits Each interface have multiple IPv6 addresses
It’s difficult to configure those IP addresses manually
MAC: 00-B0-D0-23-47-33
FE80::2B0:D0FF:FE23:4733 (link-local address)
FEC0::F282:2B0:D0FF:FE23:4733 (site-local address)3FFE:2900:D005:F282:2B0:D0FF:FE23:4733
(global address)
FF02::1:FF23:4733 (solicited-node address)
Host A
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IPv6 Address Structure Review
Link-local address
• FE80 :: XXXX:XXXX:XXXX:XXXX
(Fixed Prefix) (Interface ID)
1111 1110 10 Interface ID
10 bits 64 bits
000 . . . 000
54 bits
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IPv6 Address Structure Review
Site-local address
• FEC0 :: SSSS : XXXX:XXXX:XXXX:XXXX
(Fixed) (Subnet ID)
Prefix (Interface ID)
1111 1110 11 Interface ID
10 bits 64 bits
000 . . . 000
38 bits
Subnet ID
16 bits
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IPv6 Address Structure Review
Aggregatable global address
• Prefix + 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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IPv6 Address Structure Review
Solicited-node address
• FF02::1:FF XX:XXXX
(Fixed Prefix) (last 24 bits of Interface ID)
104 bits
Interface ID
64 bits
Unicast prefix
64 bits
FF02:
24 bits
:1:FF0:0:0:0 XX:XXXX
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ccccccug cccccccc cccccccc xxxxxxxx xxxxxxxx xxxxxxxx11111111 11111110
0xFF 0xFEEUI-64 Address
ccccccug cccccccc cccccccc
24 bits 24 bits
xxxxxxxx xxxxxxxx xxxxxxxx
IEEE 802 Address (MAC)
ccccccUg cccccccc cccccccc
64 bits
11111111 11111110 xxxxxxxx xxxxxxxx xxxxxxxx
Interface ID
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How to Autoconfigure AddressIPv6 address: Prefix + Interface ID
Interface ID is converted from MAC Link-local address
• Prefix FE80:: is fixed• Can be determined even without a router and a DHCPv6
server Site-local address ,aggregatable global address
• Prefix can be determined by Prefix Information options in Router Advertisement message
Other configuration parameters
• Other configuration parameters include hop limit, reachable time, retransmission timer, MTU…
• Can be determined by Router Advertisement message
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Autoconfiguration ProcessFor IPv6 node: 1. Derive tentative link-local address based on FE80::/64 and
a EUI-64-derived Interface ID. 2. Using Duplicate Address Detection to verify the uniqueness
of the tentative link-local address. 3. If a Neighbor Advertisement message is received, address
auto-configuration stops. Manual configure or assign a new Interface ID (must do Duplicate Address Detection either) to this interface.
4. If NO Neighbor Advertisement message is received, the tentative link-local address is valid and the link-layer multicast address of the corresponding solicited-node address is registered.
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Autoconfiguration ProcessFor IPv6 host: 1. The host sends a Router Solicitation message. 2. If NO Router Advertisement messages are received, the
host uses a stateful address auto-configuration protocol to obtain addresses and other configuration parameters.
3. If a Router Advertisement message is received, the host sets configuration parameters (hop limit, reachable time, retransmission timer, MTU…).
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Autoconfiguration Process 4. For each Prefix Information option present:
• If the On-Link flag is set to 1, the prefix is added to the prefix list.• If the Autonomous flag is set to 1, the prefix and an appropriate Interface ID
are used to derive a tentative address.• Use duplicate address detection to verify the uniqueness of the tentative
address.– If the tentative address is in use, don’t use the address to initialize the
interface.
– If the tentative address is not in use, the address is initialized. If needed, registers the new link-layer multicast address of the corresponding solicited-node address.
5. If the Managed Address Configuration flag is set to 1, a stateful address auto-configuration protocol is used to obtain additional addresses.
6. If the Other Stateful Configuration flag is set to 1, a stateful address auto-configuration protocol is used to obtain additional configuration parameters.
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Use stateful addressconfiguration protocol.
Derive link-local address:FE80::[Interface ID]
Send multicast Neighbor Solicitation with
Target Address set to derived link-local address.
Neighbor Advertisement
response received?
Yes
No
Initialize link-local address.
Send Router Solicitation.
Set Hop Limit, Reachable Time, Retrans Timer, MTU.
Are PrefixInformation
optionspresent?
Yes
NoStop address autoconfiguration.
A
Router Advertisement
response received?
No
Yes
Use stateful addressconfiguration protocol.
Is Other
Stateful Configuration
flag set to 1?
Yes
No
Stop address autoconfiguration.
Is Managed Address
Configuration flagset to 1?
No
Yes
B
Deal with Prefix Info Options
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Is On-Link flagset to 1?
Yes
No
Add prefix to prefix list.
Derive stateless address:Prefix + Interface ID
Initialize stateless address.
Neighbor Advertisement
response received?
No
Yes Do not initialize stateless address.
Are there more
Prefix Information options to process?
No
Yes
A
B
Get first Prefix Information option.
Send multicast Neighbor Solicitation with Target Address set to derived stateless address.
Is Autonomous
flagset to 1?
No
Yes Go to next Prefix Information option.
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① Send Multicast Listener Report
Ethernet Header• Destination MAC is 33-33-FF-23-47-33IPv6 Header• Source Address is ::• Destination Address is FF02::1:FF23:4733• Hop limit is 1Multicast Listener Report Header• Multicast Address is FF02::1:FF23:4733
Router
Host A
MAC: 00-B0-D0-23-47-33IP: ::
MAC: 0010FFD658C0IP: FE80::210:FFFF:FED6:58C0
FEC0:0:0:F282:210:FFFF:FED6:58C03FFE:2900:D005:F282:210:FFFF:FED6:58C0
Host B
Multicast Listener Report
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② Send Router Solicitation
Router
Host A
MAC: 00-B0-D0-23-47-33IP: ::
Host B
Router Solicitation
Ethernet Header• Destination MAC is 33-33-00-00-00-02IPv6 Header• Source Address is :: • Destination Address is FF02::2• Hop limit is 255Router Solicitation Header
MAC: 0010FFD658C0IP: FE80::210:FFFF:FED6:58C0
FEC0:0:0:F282:210:FFFF:FED6:58C03FFE:2900:D005:F282:210:FFFF:FED6:58C0
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③ Send Neighbor Solicitation
Router
Host A
MAC: 00-B0-D0-23-47-33IP: ::
Host B
Ethernet Header• Destination MAC is 33-33-FF-23-47-33IPv6 Header• Source Address is ::• Destination Address is FF02::1:FF23:4733• Hop limit is 255Neighbor Solicitation Header• Target Address is FE80::2B0:D0FF:FE23:4733
Neighbor Solicitation
MAC: 0010FFD658C0IP: FE80::210:FFFF:FED6:58C0
FEC0:0:0:F282:210:FFFF:FED6:58C03FFE:2900:D005:F282:210:FFFF:FED6:58C0
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④ Send Router Advertisement
Router
Host A
MAC: 00-B0-D0-23-47-33IP: ::
Host B
Router Advertisement
Ethernet Header• Destination MAC is 33-33-00-00-00-01IPv6 Header• Source Address is FE80::210:FFFF:FED6:58C0• Destination Address is FF02::1• Hop limit is 255Router Advertisement Header• Current Hop Limit = 64• Router Lifetime = 1800• Source Link-Layer Address is 00-10-FF-D6-58-C0• Prefix Information is for FEC0:0:0:F282::
•Valid Lifetime = 2592000•Preferred Lifetime = 604800
• Prefix Information is for 3FFE:2900:D005:F282::
MAC: 0010FFD658C0IP: FE80::210:FFFF:FED6:58C0
FEC0:0:0:F282:210:FFFF:FED6:58C03FFE:2900:D005:F282:210:FFFF:FED6:58C0
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⑤ Send Neighbor Solicitation
Router
Host A
MAC: 00-B0-D0-23-47-33IP: ::
Host B
Ethernet Header• Destination MAC is 33-33-FF-23-47-33IPv6 Header• Source Address is ::• Destination Address is FF02::1:FF23:4733• Hop limit is 255Neighbor Solicitation Header• Target Address is FEC0::F282:2B0:D0FF:FE23:4733
Neighbor Solicitation
MAC: 0010FFD658C0IP: FE80::210:FFFF:FED6:58C0
FEC0:0:0:F282:210:FFFF:FED6:58C03FFE:2900:D005:F282:210:FFFF:FED6:58C0
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⑥ Send Neighbor Solicitation
Router
Host A
MAC: 00-B0-D0-23-47-33IP: ::
Host B
Ethernet Header• Destination MAC is 33-33-FF-23-47-33IPv6 Header• Source Address is ::• Destination Address is FF02::1:FF23:4733• Hop limit is 255Neighbor Solicitation Header• Target Address is 3FFE:2900:D005:F282:2B0:D0FF:FE23:4733
Neighbor Solicitation
MAC: 0010FFD658C0IP: FE80::210:FFFF:FED6:58C0
FEC0:0:0:F282:210:FFFF:FED6:58C03FFE:2900:D005:F282:210:FFFF:FED6:58C0
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Router
Host A
MAC: 00-B0-D0-23-47-33IP: FE80::2B0:D0FF:FE23:4733
FEC0::F282:2B0:D0FF:FE23:4733 3FFE:2900:D005:F282:2B0:D0FF:FE23:4733
Host B
⑦ NO Neighbor Advertisement message received
MAC: 0010FFD658C0IP: FE80::210:FFFF:FED6:58C0
FEC0:0:0:F282:210:FFFF:FED6:58C03FFE:2900:D005:F282:210:FFFF:FED6:58C0
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Autoconfigured Address States Tentative
• The address is in the process of being verified as unique Valid
• An address from which unicast traffic can be sent and received
• Preferred state– An address for which uniqueness has been verified, unrestricted
use
• Deprecated state– An address that is still valid, but is discouraged for new
communication
Invalid
• An address for which a node can no longer send or receive unicast traffic
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Autoconfigured Address States
Tentative Preferred Deprecated Invalid
Preferred Lifetime
Valid
Valid Lifetime
time
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Types of Autoconfiguration Stateless
• Receipt of Router Advertisement messages with one or more Prefix Information options
Stateful
• Use of a stateful address configuration protocol such as DHCPv6
Both
• Receipt of Router Advertisement messages and stateful configuration protocol
For all types, a link-local address is always configured automatically.
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Q & A
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IPv6 Training Courses
Date Subject Lecturer
Introduction to IPv6
IPv6 Addressing
IPv6 Header & Extensions
Neighbor Discovery Protocol
Multicast Listener Discovery
IPv6 Routing
ICMPv6
Address Autoconfiguration
Joe Zhao
Milo Liu
Joe Zhao
Feng Zhou
Billy Bian
Jeffrey Zhou
Feng Zhou
Milo Liu
03/10
03/16
03/23
03/27
03/30
04/06
04/11
04/13
ZyXEL Confidential
IPv6 Training Courses
Date Subject Lecturer
Setting Up an IPv6 Test Lab
IPv6 Migration Mechanisms
IPv6 Mobility
Joe Zhao
Milo Liu
04/20
04/27