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Address Autoconfiguration

Address Autoconfiguration. Feng Zou SW2 ZyXEL Communications Corp. 04/11/2006. 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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Address Autoconfiguration

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  1. Address Autoconfiguration Feng Zou SW2 ZyXEL Communications Corp. 04/11/2006

  2. Outline • Why We Need Address Autoconfiguration? • IPv6 Address Structure Review • How to Autoconfiguration? • Autoconfiguration Process • Autoconfigured Address States • Types of Autoconfiguration • Q&A

  3. 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

  4. 10 bits 54 bits 64 bits 1111 1110 10 000 . . . 000 Interface ID IPv6 Address Structure Review • Link-local address • FE80 ::XXXX:XXXX:XXXX:XXXX (Fixed Prefix)(Interface ID)

  5. 10 bits 38 bits 16 bits 64 bits 1111 1110 11 000 . . . 000 Subnet ID Interface ID IPv6 Address Structure Review • Site-local address • FEC0 ::SSSS :XXXX:XXXX:XXXX:XXXX (Fixed)(Subnet ID) Prefix(Interface ID)

  6. 13 bits 8 bits 24 bits 16 bits 64 bits 001 TLA ID Res NLA ID SLA ID Interface ID IPv6 Address Structure Review • Aggregatable global address • Prefix + Interface ID

  7. IPv6 Address Structure Review • Solicited-node address • FF02::1:FFXX:XXXX (Fixed Prefix)(last 24 bits of Interface ID) 64 bits 64 bits Unicast prefix Interface ID 104 bits 24 bits FF02: 0:0:0:0 :1:FF XX:XXXX

  8. 24 bits 24 bits ccccccug cccccccc cccccccc xxxxxxxx xxxxxxxx xxxxxxxx IEEE 802 Address (MAC) EUI-64 Address 0xFF 0xFE ccccccug cccccccc cccccccc 11111111 11111110 xxxxxxxx xxxxxxxx xxxxxxxx ccccccUg cccccccc cccccccc 11111111 11111110 xxxxxxxx xxxxxxxx xxxxxxxx Interface ID 64 bits

  9. How to Autoconfigure Address IPv6 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

  10. Autoconfiguration Process For 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 newInterface ID (must doDuplicate 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 multicastaddress of the corresponding solicited-node address is registered.

  11. Autoconfiguration Process For 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…).

  12. 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.

  13. Derive link-local address: FE80::[Interface ID] Set Hop Limit, Reachable Time, Retrans Timer, MTU. A Send multicast Neighbor Solicitation with Target Address set to derived link-local address. Are Prefix Information options present? Deal with Prefix Info Options Yes B Stop address autoconfiguration. Neighbor Advertisement response received? Yes No Is Managed Address Configuration flag set to 1? Yes No Initialize link-local address. Is Other Stateful Configuration flag set to 1? Router Advertisement response received? No Send Router Solicitation. Yes Use stateful address configuration protocol. No Use stateful address configuration protocol. No Yes Stop address autoconfiguration.

  14. A Get first Prefix Information option. Neighbor Advertisement response received? Yes Do not initialize stateless address. Is On-Link flag set to 1? No Yes Add prefix to prefix list. Initialize stateless address. B No Are there more Prefix Information options to process? Is Autonomous flag set to 1? No No Go to next Prefix Information option. Yes Yes Derive stateless address: Prefix + Interface ID Send multicast Neighbor Solicitation with Target Address set to derived stateless address.

  15. Host A MAC: 00-B0-D0-23-47-33 IP: :: • Ethernet Header • Destination MAC is 33-33-FF-23-47-33 • IPv6 Header • Source Address is :: • Destination Address is FF02::1:FF23:4733 • Hop limit is 1 • Multicast Listener Report Header • Multicast Address is FF02::1:FF23:4733 ①Send Multicast Listener Report Multicast Listener Report MAC: 0010FFD658C0 IP: FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0 Router Host B

  16. Host A MAC: 00-B0-D0-23-47-33 IP: :: • Ethernet Header • Destination MAC is 33-33-00-00-00-02 • IPv6 Header • Source Address is :: • Destination Address is FF02::2 • Hop limit is 255 • Router Solicitation Header ②Send Router Solicitation Router Solicitation MAC: 0010FFD658C0 IP: FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0 Router Host B

  17. Host A MAC: 00-B0-D0-23-47-33 IP: :: • Ethernet Header • Destination MAC is 33-33-FF-23-47-33 • IPv6 Header • Source Address is :: • Destination Address is FF02::1:FF23:4733 • Hop limit is 255 • Neighbor Solicitation Header • Target Address is FE80::2B0:D0FF:FE23:4733 ③ Send Neighbor Solicitation Neighbor Solicitation MAC: 0010FFD658C0 IP: FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0 Router Host B

  18. Host A MAC: 00-B0-D0-23-47-33 IP: :: • Ethernet Header • Destination MAC is 33-33-00-00-00-01 • IPv6 Header • Source Address is FE80::210:FFFF:FED6:58C0 • Destination Address is FF02::1 • Hop limit is 255 • Router 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:: Router Advertisement ④Send Router Advertisement MAC: 0010FFD658C0 IP: FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0 Router Host B

  19. Host A MAC: 00-B0-D0-23-47-33 IP: :: • Ethernet Header • Destination MAC is 33-33-FF-23-47-33 • IPv6 Header • Source Address is :: • Destination Address is FF02::1:FF23:4733 • Hop limit is 255 • Neighbor Solicitation Header • Target Address is FEC0::F282:2B0:D0FF:FE23:4733 ⑤ Send Neighbor Solicitation Neighbor Solicitation MAC: 0010FFD658C0 IP: FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0 Router Host B

  20. Host A MAC: 00-B0-D0-23-47-33 IP: :: • Ethernet Header • Destination MAC is 33-33-FF-23-47-33 • IPv6 Header • Source Address is :: • Destination Address is FF02::1:FF23:4733 • Hop limit is 255 • Neighbor Solicitation Header • Target Address is 3FFE:2900:D005:F282:2B0:D0FF:FE23:4733 ⑥ Send Neighbor Solicitation Neighbor Solicitation MAC: 0010FFD658C0 IP: FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0 Router Host B

  21. Host A MAC: 00-B0-D0-23-47-33 IP: FE80::2B0:D0FF:FE23:4733 FEC0::F282:2B0:D0FF:FE23:4733 3FFE:2900:D005:F282:2B0:D0FF:FE23:4733 ⑦NO Neighbor Advertisement message received MAC: 0010FFD658C0 IP: FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0 Router Host B

  22. 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

  23. Valid Tentative Preferred Deprecated Invalid time Preferred Lifetime Valid Lifetime Autoconfigured Address States

  24. 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.

  25. Q & A

  26. Date Subject Lecturer 03/10 Introduction to IPv6 Joe Zhao IPv6 Addressing 03/16 Milo Liu 03/23 IPv6 Header & Extensions Joe Zhao 03/27 ICMPv6 Feng Zhou Neighbor Discovery Protocol Billy Bian 03/30 Multicast Listener Discovery 04/06 Jeffrey Zhou Address Autoconfiguration Feng Zhou 04/11 IPv6 Routing 04/13 Milo Liu IPv6 Training Courses

  27. Date Subject Lecturer Joe Zhao 04/20 IPv6 Migration Mechanisms 04/27 IPv6 Mobility Milo Liu Setting Up an IPv6 Test Lab IPv6 Training Courses

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