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

ZyXEL Confidential 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-D 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

ZyXEL Confidential IPv6 Address Structure Review  Link-local address FE80 :: XXXX:XXXX:XXXX:XXXX (Fixed Prefix) (Interface ID) Interface ID 10 bits64 bits bits

ZyXEL Confidential IPv6 Address Structure Review  Site-local address FEC0 :: SSSS : XXXX:XXXX:XXXX:XXXX (Fixed) (Subnet ID) Prefix (Interface ID) Interface ID 10 bits64 bits bits Subnet ID 16 bits

ZyXEL Confidential IPv6 Address Structure Review  Aggregatable global address Prefix + Interface ID TLA IDInterface ID 13 bits64 bits SLA ID 24 bits 001NLA ID 16 bits Res 8 bits

ZyXEL Confidential 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

ZyXEL Confidential ccccccug cccccccc ccccccccxxxxxxxx xxxxxxxx xxxxxxxx xFF0xFE EUI-64 Address ccccccug cccccccc cccccccc 24 bits xxxxxxxx xxxxxxxx xxxxxxxx IEEE 802 Address (MAC) ccccccUg cccccccc cccccccc 64 bits xxxxxxxx xxxxxxxx xxxxxxxx Interface ID

ZyXEL Confidential 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

ZyXEL Confidential 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 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.

ZyXEL Confidential 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…).

ZyXEL Confidential 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.

ZyXEL Confidential Use stateful address configuration 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 Prefix Information options present? Yes No Stop address autoconfiguration. A Router Advertisement response received? No Yes Use stateful address configuration protocol. Is Other Stateful Configuration flag set to 1? Yes No Stop address autoconfiguration. Is Managed Address Configuration flag set to 1? No Yes B Deal with Prefix Info Options

ZyXEL Confidential Is On-Link flag set 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 flag set to 1? No Yes Go to next Prefix Information option.

ZyXEL Confidential ① Send Multicast Listener Report Ethernet Header Destination MAC is FF 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 Router Host A MAC: 00-B0-D IP::: MAC: 0010FFD658C0 IP:FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0 Host B Multicast Listener Report

ZyXEL Confidential ② Send Router Solicitation Router Host A MAC: 00-B0-D IP::: Host B Router Solicitation Ethernet Header Destination MAC is IPv6 Header Source Address is :: Destination Address is FF02::2 Hop limit is 255 Router Solicitation Header MAC: 0010FFD658C0 IP:FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0

ZyXEL Confidential ③ Send Neighbor Solicitation Router Host A MAC: 00-B0-D IP::: Host B Ethernet Header Destination MAC is FF 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 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

ZyXEL Confidential ④ Send Router Advertisement Router Host A MAC: 00-B0-D IP::: Host B Router Advertisement Ethernet Header Destination MAC is 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 FF-D6-58-C0 Prefix Information is for FEC0:0:0:F282:: Valid Lifetime = Preferred Lifetime = Prefix Information is for 3FFE:2900:D005:F282:: MAC: 0010FFD658C0 IP:FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0

ZyXEL Confidential ⑤ Send Neighbor Solicitation Router Host A MAC: 00-B0-D IP::: Host B Ethernet Header Destination MAC is FF 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 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

ZyXEL Confidential ⑥ Send Neighbor Solicitation Router Host A MAC: 00-B0-D IP::: Host B Ethernet Header Destination MAC is FF 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 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

ZyXEL Confidential Router Host A MAC: 00-B0-D IP: 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: 0010FFD658C0 IP:FE80::210:FFFF:FED6:58C0 FEC0:0:0:F282:210:FFFF:FED6:58C0 3FFE:2900:D005:F282:210:FFFF:FED6:58C0

ZyXEL Confidential 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

ZyXEL Confidential Autoconfigured Address States TentativePreferredDeprecatedInvalid Preferred Lifetime Valid Valid Lifetime time

ZyXEL Confidential 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.

ZyXEL Confidential Q & A

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