IPv 6 Prefix Delegation Options for DHCPv 6

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IPv 6 Prefix Delegation Options for DHCPv 6 Ole Troan, Ralph Droms IETF-53 1

IPv 6 Prefix Delegation Options for DHCPv 6 Ole Troan, Ralph Droms IETF-53 1

PD Options for DHCPv 6 • New options for DHCPv 6 for delegation of

PD Options for DHCPv 6 • New options for DHCPv 6 for delegation of prefixes – Prefix Request option: Requesting Router indicates interest in obtaining prefixes – Prefix Delegation option: Delegating Router assigns prefixes to Requesting Router IETF-53 2

Delegation from ISP to subscriber AAA service Delegating router ISP core network Aggregation device

Delegation from ISP to subscriber AAA service Delegating router ISP core network Aggregation device CPE Requesting router Subscriber link IETF-53 Subscriber link 3

Initial delegation • Requesting router indicates interest in prefix delegation by including Prefix Request

Initial delegation • Requesting router indicates interest in prefix delegation by including Prefix Request in Solicit message • Delegating router indicates availability of prefix(es) by including Prefix option in Advertise message • Requesting router asks for prefix(es) in Request message • Delegating router delegates prefixes by including Prefix option in Reply message IETF-53 4

Delegation extension • Requesting router requests extension of lease on prefix(es) in Rebind/Renew message

Delegation extension • Requesting router requests extension of lease on prefix(es) in Rebind/Renew message • Delegating router extends lease in Reply message IETF-53 5

Prefix Request option format 0 1 2 3 4 5 6 7 8 9

Prefix Request option format 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_PREFIXREQ | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | prefix-length | num-global | num-site | +-+-+-+-+-+-+-+-+-+-+-+-+ num-global – number of global prefixes requested num-site – number of site-scoped prefixes requested IETF-53 6

Prefix Option format 0 1 2 3 4 5 6 7 8 9 0

Prefix Option format 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_IAPREFIX | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | lease-duration | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | prefix-length | IPv 6 -prefix | +-+-+-+-+ (variable length) |. . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ lease-duration – controlled by delegating router; requesting router derives preferred and valid lifetimes IPv 6 -prefix – padded to even octet boundary (/35 prefix occupies 5 octets) IETF-53 7

Collateral damage from DHCPv 6 • Clearly defined rules for use of DHCP messages

Collateral damage from DHCPv 6 • Clearly defined rules for use of DHCP messages when requesting router restarts, reconnects to link, etc. • DUID from DHCP allows delegating router to identify requesting router – for example, for lease renewal or static prefix assignment • Relay function and use of multicast allows for centralized service implementation • DHCP can carry other configuration information; spec includes process for defining additional options • Reconfigure message allows forced renumbering IETF-53 8

Status of DHCPv 6 specification • Specification has passed WG last call • Internet

Status of DHCPv 6 specification • Specification has passed WG last call • Internet AD has responded with editorial comments • Authors will rev spec and publish new draft • Next rev of spec will be ready for IETF last call IETF-53 9

Simplifying DHCP • Requesting and delegating routers can implement prefix delegation function without address

Simplifying DHCP • Requesting and delegating routers can implement prefix delegation function without address assignment or “identity associations” • IPsec with link-local addresses (may) eliminate need for DHCP authentication • Only a subset of messages and protocol specification required for prefix delegation and configuration • Guidelines for prefix delegation and configuration requirements to be published as Internet Draft IETF-53 10

Open Issues • Two message exchange (Informationrequest/Reply) for prefix delegation • Use of IPsec

Open Issues • Two message exchange (Informationrequest/Reply) for prefix delegation • Use of IPsec for authentication if requesting router has address of appropriate scope • Use of anycast (e. g. , for NBMA networks) • Name: Dynamic Host Configuration Protocol – – IETF-53 Dynamic Node Configuration Protocol? Dynamic Configuration Protocol? Simple Configuration Protocol? Droms-Haberman Configuration Protocol? 11

Delegation from ISP to subscriber AAA service f. Authenticate Aggregation ISP core network device

Delegation from ISP to subscriber AAA service f. Authenticate Aggregation ISP core network device Authorizeg Advertisei i. Reply Solicith h. Request CPE is assigned 2000: 0: 100: : /48 CPE assigns 2000: 0: 100: 1: /64 and 2000: 0: 100: 2: /64 to other “downstream” interfaces IETF-53 CPE Subscriber link 12