wiki:prefix_delegation

Prefix Delegation Overview:

Prefix delegation with DHCP is independent of address assignment with DHCP. A requesting router can use DHCP for just prefix delegation or for prefix delegation along with address assignment and other configuration information. A requesting router first creates an IA_PD and assigns it an IAID.The requesting router then transmits a Solicit message containing an IA_PD option describing the IA_PD. Delegating routers that can delegate prefixes to the IA_PD respond to the requesting router with an Advertise message. When the requesting router has identified a delegating router, the requesting router uses a Request message to populate the IA_PDs with prefixes. The requesting router includes one or more IA_PD options in the Request message. The delegating router returns prefixes and other information about the IA_PDs to the requesting router in IA_PD options in a Reply message. The requesting router records the lifetimes for the delegated prefix(es) and uses the prefix(es) as described in the previous section.

Table describes the requirements for the DHCPv6 Prefix Delegation to be tested (not specific test scenario). Unless otherwise specified, "Reference Number" column designates section in RFC3633.

Number Reference Number Requirement Notes
1 9. An IA_PD option may only appear in the options area of a DHCP message. A DHCP message may contain multiple IA_PD options.
2 9. The status of any operations involving this IA_PD is indicated in a Status Code option in the IA_PD-options field.
3 10. The IA_PD Prefix option is used to specify IPv6 address prefixes associated with an IA_PD. The IA_PD Prefix option must be encapsulated in the IA_PD-options field of an IA_PD option.
4 10. An IA_PD Prefix option may appear only in an IA_PD option. More than one IA_PD Prefix Option can appear in a single IA_PD option.
5 11.2. The delegating router sends an Advertise message to the requesting router in the same way as described in section 17.2.2, "Creation and transmission of Advertise messages" of RFC 3315. RFC3315
6 11.2. The delegating router MUST include an IA_PD option, identifying any prefix(es) that the delegating router will delegate to the requesting router. .. a Server Identifier option with the delegating router's DUID and a Client Identifier option with the requesting router's DUID.
7 11.2. If the delegating router will not assign any prefixes to any IA_PDs in a subsequent Request from the requesting router, the delegating router MUST send an Advertise message to the requesting router that includes the IA_PD with no prefixes in the IA_PD and a Status Code option in the IA_PD containing status code NoPrefixAvail?
8 12. A requesting router uses the same message exchanges as described in section 18, "DHCP Client-Initiated Configuration Exchange" of RFC 3315 RFC3315
9 12.1. The requesting router uses a Request message to populate IA_PDs with prefixes. The requesting router includes one or more IA_PD options in the Request message.
10 12.1. The requesting router includes IA_PD options in any Renew, or Rebind messages sent by the requesting router. The IA_PD option includes all of the prefixes the requesting router currently has associated with that IA_PD.
11 12.1. The requesting router uses a Release message to return a delegated prefix to a delegating router. The prefixes to be released MUST be included in the IA_PDs.
12 12.2. When a delegating router receives a Request message from a requesting router that contains an IA_PD option, and the delegating router is authorized to delegate prefix(es) to the requesting router
13 12.2. The delegating router behaves as follows when it cannot find a binding for the requesting router's IA_PD: Renew message: If the delegating router cannot find a binding for the requesting router's IA_PD the delegating router returns the IA_PD containing no prefixes with a Status Code option set to NoBinding? in the Reply message.
14 12.2. The delegating router behaves as follows when it cannot find a binding for the requesting router's IA_PD: Rebind message: If the delegating router cannot find a binding for the requesting router's IA_PD and the delegating router determines that the prefixes in the IA_PD are not appropriate for the link to which the requesting router's interface is attached according to the delegating routers explicit configuration, the delegating router MAY send a Reply message to the requesting router containing the IA_PD with the lifetimes of the prefixes in the IA_PD set to zero.
15 13.1. The delegating router initiates a configuration message exchange with a requesting router, as described in section 19, "DHCP Server-Initiated Configuration Exchange" of RFC 3315 recofigure
16 14. A relay agent forwards messages containing Prefix Delegation options in the same way as described in section 20, "Relay Agent Behavior" of RFC 3315.
Last modified 4 years ago Last modified on Sep 2, 2013, 8:50:54 AM