draft-ietf-dhc-host-gen-id-03.txt   draft-ietf-dhc-host-gen-id-04.txt 
Network Working Group S. Jiang Network Working Group S. Jiang, Ed.
Internet-Draft F. Xia Internet-Draft F. Xia
Intended status: Standards Track B. Sarikaya Intended status: Standards Track B. Sarikaya
Expires: February 22, 2013 Huawei Technologies Expires: March 3, 2013 Huawei Technologies
August 21, 2012 August 30, 2012
Prefix Assignment in DHCPv6 Prefix Assignment in DHCPv6
draft-ietf-dhc-host-gen-id-03 draft-ietf-dhc-host-gen-id-04
Abstract Abstract
This document introduces a generic prefix announcement mechanism This document introduces a generic host-oriented prefix assignment
using DHCPv6. In this new address configuration procedure, the mechanism using DHCPv6. In this new address configuration procedure,
prefix is propagated from a DHCPv6 server to hosts through DHCPv6 the prefix is assigned from a DHCPv6 server to hosts through DHCPv6
message exchanging while the interface identifiers are independently message exchanging while the interface identifiers are independently
generated by the hosts. It enables both integral address assignment generated by the hosts. It enables both integral address assignment
and self-generated addresses in one single mechanism, DHCPv6. It and self-generated addresses in one single mechanism, DHCPv6. It
also enables stateless address configuration without RA attendance. also enables stateless address configuration without RA attendance.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on February 22, 2013. This Internet-Draft will expire on March 3, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Address Auto-configuration . . . . . . . . . . . . . . . . . . 4 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4
4. DHCPv6 Operation . . . . . . . . . . . . . . . . . . . . . . . 5 4. Address Auto-configuration . . . . . . . . . . . . . . . . . . 5
5. DHCPv6 IA_PA Option . . . . . . . . . . . . . . . . . . . . . 6 5. DHCPv6 Operation . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Identity Association for Prefix Assignment Option . . . . 7 6. DHCPv6 IA_PA Option . . . . . . . . . . . . . . . . . . . . . 7
5.2. IA_PA Prefix Option . . . . . . . . . . . . . . . . . . . 8 6.1. Identity Association for Prefix Assignment Option . . . . 7
6. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 8 6.2. IA_PA Prefix Option . . . . . . . . . . . . . . . . . . . 9
7. IANA consideration . . . . . . . . . . . . . . . . . . . . . . 9 7. IANA consideration . . . . . . . . . . . . . . . . . . . . . . 9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . . 9
10.2. Informative references . . . . . . . . . . . . . . . . . . 10 10.2. Informative references . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
skipping to change at page 3, line 21 skipping to change at page 3, line 21
is responsible for the assignment of an integral address which is responsible for the assignment of an integral address which
includes both prefix and interface identifier parts as described in includes both prefix and interface identifier parts as described in
[RFC4291]. In the Stateless Address Autoconfiguration (SLACC, [RFC4291]. In the Stateless Address Autoconfiguration (SLACC,
[RFC4862]) model, the interface Identifier is generated by the host [RFC4862]) model, the interface Identifier is generated by the host
itself while the prefix is configured through Router Advertisement itself while the prefix is configured through Router Advertisement
message defined in [RFC4861]. message defined in [RFC4861].
However, in a DHCPv6-managed network, assigning 128-bit address is However, in a DHCPv6-managed network, assigning 128-bit address is
insufficient. Some hosts may want to use self-generated address, insufficient. Some hosts may want to use self-generated address,
which are combined by prefixes obtained from network configuration which are combined by prefixes obtained from network configuration
and interface identifiers generated by hosts. The examples include and interface identifiers generated by hosts. The applicable user
CGA [RFC3972], modified EUI-64 interface identifier [EUI-64], cases include CGA [RFC3972], modified EUI-64 interface identifier
temporary addresses for privacy [RFC4941] and etc. [EUI-64], temporary addresses for privacy [RFC4941] and etc.
In these scenarios, the address configuration precedure has to be In these scenarios, the address configuration precedure has to be
splitted in two motheds: integral address assignment through DHCPv6 splitted in two motheds: integral address assignment through DHCPv6
and prefix announcement by RA advertisement. Some ISPs desire to and prefix announcement by RA advertisement. Some ISPs desire to
manage address configuration using one set of protocol, rather than manage address configuration using one set of protocol, rather than
mixture of DHCPv6 and Neighbor Discovery. mixture of DHCPv6 and Neighbor Discovery.
There are also some network environments in that perfix annoucement There are also some network environments in that perfix annoucement
through RAs may not be the best choice. For example, hosts may through RAs may not be the best choice. For example, hosts may
connect through tunnels, either layer 2 tunnels or layer 3 tunnels. connect through tunnels, either layer 2 tunnels or layer 3 tunnels.
While a RA is only able to announce prefix on a single link, DHCPv6 While a RA is only able to announce prefix on a single link, DHCPv6
configuration can be used to manage multiple links by setup DHCPv6 configuration can be used to manage multiple links by setup DHCPv6
relay. relay.
Up to now, there is no mechanism for the prefix announcement/ Up to now, there is no mechanism for host-oriented prefix assignment
assignment in DHCPv6. [RFC3633] defines Prefix Delegation options in DHCPv6. [RFC3633] defines Prefix Delegation options providing a
providing a mechanism for automated delegation of IPv6 prefixes using mechanism for automated delegation of IPv6 prefixes using the DHCPv6.
the DHCPv6. This mechanism is intended for delegating a long-lived This mechanism is intended for delegating a long-lived prefix from a
prefix from a delegating router to a requesting router. This delegating router to a requesting router. This mechanism "is not
mechanism "is not bound to the assignment of IP addresses or other bound to the assignment of IP addresses or other configuration
configuration information to hosts" [RFC3633]. It delegates prefixes information to hosts" [RFC3633]. It delegates prefixes to a routable
to a routable device for itself use only. It does not support the device for itself use only. It does not support the host-generated
host-generated interface identifiers model, in which prefix(es) need interface identifiers model, in which prefix(es) need to be
to be advertised or assigned to hosts. propagated to hosts.
This document introduces a generic prefix announcement mechanism This document introduces a generic prefix assignment mechanism using
using DHCPv6. In this new address configuration procedure, the DHCPv6. In this new address configuration procedure, the prefix is
prefix is propagated from a DHCPv6 server to hosts through DHCPv6 propagated from a DHCPv6 server to hosts through DHCPv6 message
message exchanging while the interface identifiers are independently exchanging while the interface identifiers are independently
generated by the hosts. It is alternative of RA prefix assignment/ generated by the hosts. It enables both integral address assignment
announcement. It enables both integral address assignment and self- and self-generated addresses in one single mechanism, DHCPv6. Note,
generated addresses in one single mechanism, DHCPv6. Note, in many in many scenarios, Neighbor Discovery [RFC4861] is still needed for
scenarios, neighbor discovery is still needed for routing and routing and reachability. In other scenarios, this mechanism enables
reachability. In other scenarios, this mechanism enables stateless stateless address configuration while RA absents.
address configuration while RA absents.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
The terminology in this document is based on the definitions in The terminology in this document is mainly based on the definitions
[RFC3315], in addition to the ones specified in this section in [RFC3315] and [RFC3633].
derivative prefix: A prefix is derived from another prefix. For Prefix assignment: a DHCPv6 server propagates prefix information to
example, a /64 prefix is derived from a /48 prefix, that is, the hosts in unicast model.
/64 prefix has the same leftmost 48 bits with the /48 prefix.
authorized prefix: A specific router is given a specific set of
subnet prefixes to advertise; other routers have an authorization
to advertise other subnet prefixes. In [RFC3971],Certification
Path Advertisement message is used to convey authorized prefixes.
3. Address Auto-configuration 3. Applicability
Router Advertisements in [RFC4861] allow routers to inform hosts how In point-to-point link model, DHCPv6 operation with host-generated
to perform Address Auto-configuration. For example, routers can interface identifier, described in this document, may be used.
[RFC4968] provides different IPv6 link models that are suitable for
802.16 based networks and a point-to-point link model is recommended.
Also, 3GPP and 3GPP2 have earlier adopted the point-to-point link
model based on the recommendations in [RFC3314]. In this model, one
prefix can only be assigned to one interface of a host (mobile
station) and different hosts (mobile stations) can't share a prefix.
The unique prefix can be used to identify the host. It is not
necessary for a DHCPv6 server to generate an interface identifier for
the host. The host may generate its interface identifier as
described in [RFC4941]. An interface identifier could even be
generated via random number generation.
[RFC3972] defines Cryptographically Generated Addresses (CGA), which
is generated from a giving prefix and a public signature key. For
security reasons, it is only proper to be generated the user, the
host itself. It requests a prefix before the interface identifier
can be computed.
Modified EUI-64 interface identifier [EUI-64] is also typically
generated by hosts. [RFC4941] has defined temporary addresses for
privacy purposes. The temporary addresses is also generated by hosts
using random algorithm.
The DHCPv6 operations defined in this document supports
abovementioned address methods, and the host-generated addresses that
may defined in the future.
4. Address Auto-configuration
Router Advertisements in ND [RFC4861] allow routers to inform hosts
how to perform Address Auto-configuration. For example, routers can
specify whether hosts should use DHCPv6 and/or stateless address specify whether hosts should use DHCPv6 and/or stateless address
configuration. In Router Advertisement message, M and O bits are configuration. In Router Advertisement message, M and O bits are
used for indication of address auto-configuration mode. used for indication of address auto-configuration mode.
Whatever address auto-configuration mode a host uses, the following Whatever address auto-configuration mode a host uses, the following
two parts are necessary for the host to formulate it's IPv6 address: two parts are necessary for the host to formulate it's IPv6 address:
o A prefix. In [RFC3971], Certification Path Solicitation and o A prefix. "A bit string that consists of some number of initial
Certification Path Advertisement messages are designed for bits of an address" [RFC4861]. The prefixes can be announced
verifying routers being authorized to act as routers. through Router Advertisement message. Prefix assignment from a
Certification Path Advertisement message can also be used to DHCPv6 server is not currently support.
verify that routers are authorized to advertise a certain set of o An interface identifier. "From address autoconfiguration's
subnet prefixes. In the stateless auto-configuration address perspective, an interface identifier is a bit string of known
mode, the prefixes in Router Advertisement message should be a length" [RFC4862]. Modified EUI-64 interface identifier [EUI-64]
subset of authorized prefixes, or derivative prefixes from is a widely-used host generated interface identifier. It
authorized prefixes. In the stateful auto-configuration address
mode, prefix assignment from a DHCPv6 server is not currently
support.
o An interface identifier. Modified EUI-64 interface identifier
[EUI-64] is a widely-used host generated interface identifier. It
generates interface identifier from the host MAC address. The generates interface identifier from the host MAC address. The
interface identifier of [RFC3972] is generated by computing a interface identifier of CGA [RFC3972] is generated by computing a
cryptographic hash of a public key of a host. The host is preifx that will be used to form the CGA and a cryptographic hash
responsible for interface identifier generation. of a public key of a host. The host is responsible for interface
identifier generation.
In the ND-managed environment, RA is used to assign the prefix. In the ND-managed environment, RA is used to assign the prefix.
So far, there is no mechanism to support the scenario that prefixes So far, there is no mechanism to support the scenario that prefixes
are managed by a DHCPv6 server. This document targets to meet this are managed by a DHCPv6 server. This document targets to meet this
gap. The DHCPv6 operation defined in this document enables the gap. The DHCPv6 operation defined in this document enables the
DHCPv6 server to assign a prefix, rather than a integral address, to DHCPv6 server to assign a prefix, rather than a integral address, to
the host, so that the host can obtain an IPv6 address by combining the host, so that the host can obtain an IPv6 address by combining
the prefix with its own generated interface identifier. It actually the prefix with its own generated interface identifier. It enables
enables the auto address configuration through DHCPv6. the auto address configuration through DHCPv6.
4. DHCPv6 Operation 5. DHCPv6 Operation
Figure 1 shows the operation of separating prefix assignment and Figure 1 shows the operation of separating prefix assignment and
interface identifier generation in the DHCPv6. interface identifier generation in the DHCPv6.
+------------+ +-------------+ +------------+ +-------------+
|Host(Client)| |DHCPv6 Server| |Host(Client)| |DHCPv6 Server|
+------------+ +-------------+ +------------+ +-------------+
| 1 Solicit/Request | | 1 Solicit/Request |
|---------------------> | |---------------------> |
| 2 Advertise/Reply | | 2 Reply with IA_PA |
| with IA_PA Option |
|<--------------------- | |<--------------------- |
3 Combination of Prefix | 3 Combination of Prefix |
and Interface Identifier | and Interface Identifier |
| | | |
Figure 1: DHCPv6 Operation Figure 1: DHCPv6 Operation
1. A host uses a Solicit message to discover DHCPv6 servers that 1. A host uses a Solicit message to discover DHCPv6 servers.
have been configured to assign prefixes for the host. Identity Indications of information requests can be included in the
Association for Prefix Delegation Option (IA_PD) is defined in Solicit message or a Request message after discovery procedure.
[RFC3633] for prefix delegation between a requesting router and If a host that wants to use host generated addresses, it SHOULD
delegating router. Referring to the definition, a new Identity request prefix assignment explicitly by including an IA_PA in a
Association for Prefix Assignment (IA-PA) option is defined in Solicit or a Request message, in which an IAID is provided by the
Section 5.1 to enable the prefix assignment from a DHCPv6 server host.
to a host. A host MAY include a Option Request Option requesting 2. The DHCPv6 server assigns one or more prefixes to the host in the
IA_PA in a Solicit or a IA_PA Option in a Request message to Reply messages responding to the prefix requests from the hosts.
request prefix assignment explicitly. A server MUST return the same set of prefixes for the same IA_PA
(as identified by the IAID) as long as those prefixes are still
2. The DHCPv6 server assigns one or more prefixes to the host in valid. After the lifetimes of the prefixes in an IA_TA have
Advertise messages or in the Reply messages responding to the expired, the IAID may be reused to identify a new IA_PA with new
prefix requests from the hosts. When the prefix assignment in prefix. If there is not a proper prefix available, a
advertise model, even if a host does not request, DHCPv6 server NoPrefixAvail (defined in [RFC3633]) status-code is returned to
can push it initiatively. The assigned prefixes SHOULD be a the host and the procedure is terminated.
subset of the authorized prefixes or derivative prefixes of the
authorized prefixes. Identity Association for Prefix Assignment
Option in Section 5.1 is used for conveying the assigned
prefixes. If there is not a proper prefix available, a
NoPrefixAvail (defined in [RFC3633])status-code is returned to
the host and the procedure is terminated. When receiving
multiple prefixes, the host may use pre-configured hints for
prefix assignment preference. The hints are authorized prefixes
advertised by an authorized router through Certification Path
Advertisement defined in [RFC3971].
3. The host generates an interface identifier and formulates a 3. The host generates an interface identifier and formulates a
combined IPv6 address by concatenating the assigned prefix and combined IPv6 address by concatenating the assigned prefix and
the self-generated interface identifier. There are many ways to the self-generated interface identifier.
generate interface identifier. [RFC3972] defines a method to
generate the interface identifier by computing a cryptographic
hash of a public key of the host. Modified EUI-64 interface
identifier [EUI-64] is generated based on the host MAC address.
After the host generates an IPv6 address using the above procedure, After the host generates an IPv6 address using the above procedure,
the host may send a Request message to the DHCPv6 server in order to the host may send a Request message to the DHCPv6 server in order to
confirm the usage of the new address. The confirmation procedure may confirm the usage of the new address. The confirmation procedure may
be completed together with the address registration procedure be completed together with the address registration procedure
[I-D.ietf-dhc-addr-registration]. However, the confirmation [I-D.ietf-dhc-addr-registration]. However, the confirmation
procedure is out of scope. procedure is out of scope.
When the host reaches T1 or T2 defined in Section 5.1, it SHOULD use When the host reaches T1 or T2 defined in Section 6.1, it SHOULD use
the same message exchanges, as described in section 18, "DHCP Client- the same message exchanges, as described in section 18, "DHCP Client-
Initiated Configuration Exchange" of [RFC3315], to obtain or update Initiated Configuration Exchange" of [RFC3315], to obtain or update
prefix(es) from a DHCPv6 server. prefix(es) from a DHCPv6 server.
A DHCPv6 server MAY initiatively send a reconfiguration message to A DHCPv6 server MAY initiatively send a reconfiguration message to
the host, as described in section 19, "DHCP Server-Initiated the host, as described in section 19, "DHCP Server-Initiated
Configuration Exchange" of [RFC3315], to cause prefix(es) information Configuration Exchange" of [RFC3315], to cause prefix(es) information
update. update.
5. DHCPv6 IA_PA Option If an IA_PA capable client connects to a network, and the DHCPv6
server is not IA_PA capable, the Solicit or Request message with
IA_PA Option will result in no Reply, Reply without IA_PAs, or Reply
with a Status Code containing UnspecFail. The client MAY decide the
network does not support IA_PA immediately or after a period of
soliciting (with limited retransmissions times). Then, it MAY
"failover" to IA_NA/IA_TA requests.
6. DHCPv6 IA_PA Option
In this section, one new option is defined, Identity Association for In this section, one new option is defined, Identity Association for
Prefix Assignment Option . The format of this new DHCPv6 IA_PA Prefix Assignment Option . The format of this new DHCPv6 IA_PA
Option has been deliberately designed to be the same with IA_PD Option has been deliberately designed to be the same with IA_PD
option[RFC3633]. The IA_PD Prefix and IA Address sub-options from option[RFC3633]. The IA_PD Prefix and IA Address sub-options from
IA_PD option are also reused. However, the two options are different IA_PD option are also reused. However, the two options are different
on the semantics and usage models. on the semantics and usage models.
The prefixed assigned through this DHCPv6 IA_PA option could be Comparing with Prefix Information Option in ND, Section 4.6.2 of
shared accross multiple hosts. [RFC4861], the IA_PA option does not provide L flag and A flag. The
A (autonomous address-configuration flag) isn't need obviously
because the IA_PA is implicit for stateless address configuration.
Because the IA_PA is only address relevant, it does not relevant to
reachability or routing and the DHCPv6 server may not sure the on-
link state. So L (on-Link) flag is not include. The DHCPv6 client
should treat the prefix as same as L flag not set, which makes no
statement about on-link or off-link properties of the prefix.
5.1. Identity Association for Prefix Assignment Option 6.1. Identity Association for Prefix Assignment Option
The IA_PA option is used to carry a prefix assignment identity The IA_PA option is used to carry a prefix assignment identity
association, the parameters associated with the IA_PA and the association, the parameters associated with the IA_PA and the
prefixes associated with it. prefixes associated with it.
The format of the IA_PA option is: The format of the IA_PA option is:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 8, line 4 skipping to change at page 8, line 20
| IAID (4 octets) | | IAID (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| T1 | | T1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| T2 | | T2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . . .
. IA_PA-options . . IA_PA-options .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_IA_PA (TBA1) option-code: OPTION_IA_PA (TBA1)
option-length: 12 + length of IA_PA-options field. option-length: 12 + length of IA_PA-options field.
IAID: The unique identifier for this IA_PA; the IAID must IAID: The unique identifier for this IA_PA; the IAID must
be unique among the identifiers for all of this be unique among the identifiers for all of this
host's IA_PAs. host's IA_PAs. The number space for IA_PA IAIDs is
separate from the number spaces for IA_TA and IA_NA
IAIDs
T1: The time at which the host should T1: The time at which the host should
contact the DHCPv6 server from which the contact the DHCPv6 server from which the
prefixes in the IA_PA were obtained to extend the prefixes in the IA_PA were obtained to extend the
lifetimes of the prefixes assigned to the IA_PA; lifetimes of the prefixes assigned to the IA_PA;
T1 is a time duration relative to the current time T1 is a time duration relative to the current time
expressed in units of seconds. expressed in units of seconds.
T2: The time at which the host should T2: The time at which the host should
contact any available DHCPv6 server to extend contact any available DHCPv6 server to extend
skipping to change at page 8, line 33 skipping to change at page 9, line 5
IA_PA; T2 is a time duration relative to the IA_PA; T2 is a time duration relative to the
current time expressed in units of seconds. current time expressed in units of seconds.
IA_PA-options: Options associated with this IA_PA. IA_PA-options: Options associated with this IA_PA.
The details of the fields are similar to the IA_PD option description The details of the fields are similar to the IA_PD option description
in [RFC3633]. The difference is here a DHCPv6 server and a host in [RFC3633]. The difference is here a DHCPv6 server and a host
involved, while a delegating router and requesting router involved in involved, while a delegating router and requesting router involved in
[RFC3633]. [RFC3633].
5.2. IA_PA Prefix Option 6.2. IA_PA Prefix Option
OPTION_IAPREFIX (26) "IA_PD Prefix Option" defined in Section 10 of OPTION_IAPREFIX (26) "IA_PD Prefix Option" defined in Section 10 of
[RFC3633] is reused. [RFC3633] is reused.
Originally, the option is used for conveying prefix information Originally, the option is used for conveying prefix information
between a delegating router and a requesting router. Here the IA_PD between a delegating router and a requesting router. Here the IA_PD
Prefix option is used to specify IPv6 address prefixes associated Prefix option is used to specify IPv6 address prefixes associated
with an IA_PA in Section 5.1. The IA_PD Prefix option must be with an IA_PA in Section 6.1. The IA_PD Prefix option must be
encapsulated in the IA_PA-options field of an IA_PA option. encapsulated in the IA_PA-options field of an IA_PA option.
6. Applicability Note, the PD_EXCLUDE option [RFC6603] SHOULD NOT be encapsulated in
the IAPREFIX options that are encapsulated in an IA_PA.
In point-to-point link model, DHCPv6 operation with host-generated
interface identifier, described in this document, may be used.
[RFC4968] provides different IPv6 link models that are suitable for
802.16 based networks and a point-to-point link model is recommended.
Also, 3GPP and 3GPP2 have earlier adopted the point-to-point link
model based on the recommendations in [RFC3314]. In this model, one
prefix can only be assigned to one interface of a host (mobile
station) and different hosts (mobile stations) can't share a prefix.
The unique prefix can be used to identify the host. It is not
necessary for a DHCPv6 server to generate an interface identifier for
the host. The host may generate its interface identifier as
described in [RFC4941]. An interface identifier could even be
generated via random number generation.
Modified EUI-64 interface identifier [EUI-64] is also typically
generated by hosts. [RFC4941] has defined temporary addresses for
privacy purposes. The temporary addresses is also generated by hosts
using random algorithm. The DHCPv6 operations defined in this
document also supports such address methods.
7. IANA consideration 7. IANA consideration
This document defines a new DHCPv6 [RFC3315] option, which must be This document defines a new DHCPv6 [RFC3315] option, which must be
assigned Option Type values within the option numbering space for assigned Option Type values within the option numbering space for
DHCPv6 messages: DHCPv6 messages:
The OPTION_IA_PA Option (TBA1), described in Section 5.1. The OPTION_IA_PA Option (TBA1), described in Section 6.1.
8. Security Considerations 8. Security Considerations
Security considerations in DHCPv6 are described in [RFC3315]. Security considerations in DHCPv6 are described in [RFC3315].
To guard against attacks through prefix assignment, a host and a To guard against attacks through prefix assignment, a host and a
DHCPv6 server SHOULD use DHCPv6 authentication as described in DHCPv6 server SHOULD use DHCPv6 authentication as described in
Section 21, "Authentication of DHCP messages" of [RFC3315] or Secure Section 21, "Authentication of DHCP messages" of [RFC3315] or Secure
DHCPv6 [I-D.ietf-dhc-secure-dhcpv6] . DHCPv6 [I-D.ietf-dhc-secure-dhcpv6] .
skipping to change at page 10, line 13 skipping to change at page 10, line 13
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003. IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633, Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003. December 2003.
[RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
Neighbor Discovery (SEND)", RFC 3971, March 2005.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, March 2005. RFC 3972, March 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006. Architecture", RFC 4291, February 2006.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007. September 2007.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007. Address Autoconfiguration", RFC 4862, September 2007.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007. IPv6", RFC 4941, September 2007.
[RFC6603] Korhonen, J., Savolainen, T., Krishnan, S., and O. Troan,
"Prefix Exclude Option for DHCPv6-based Prefix
Delegation", RFC 6603, May 2012.
10.2. Informative references 10.2. Informative references
[RFC3314] Wasserman, M., "Recommendations for IPv6 in Third [RFC3314] Wasserman, M., "Recommendations for IPv6 in Third
Generation Partnership Project (3GPP) Standards", Generation Partnership Project (3GPP) Standards",
RFC 3314, September 2002. RFC 3314, September 2002.
[RFC4968] Madanapalli, S., "Analysis of IPv6 Link Models for 802.16 [RFC4968] Madanapalli, S., "Analysis of IPv6 Link Models for 802.16
Based Networks", RFC 4968, August 2007. Based Networks", RFC 4968, August 2007.
[I-D.ietf-dhc-secure-dhcpv6] [I-D.ietf-dhc-secure-dhcpv6]
skipping to change at page 11, line 11 skipping to change at page 11, line 11
Registration Solution Using DHCPv6", Registration Solution Using DHCPv6",
draft-ietf-dhc-addr-registration-00 (work in progress), draft-ietf-dhc-addr-registration-00 (work in progress),
May 2012. May 2012.
[EUI-64] "Guidelines for 64-bit Global Identifier (EUI-64) [EUI-64] "Guidelines for 64-bit Global Identifier (EUI-64)
Registration Authority", http://standards.ieee.org/ Registration Authority", http://standards.ieee.org/
regauth/oui/tutorials/EUI64.html", March 1997. regauth/oui/tutorials/EUI64.html", March 1997.
Authors' Addresses Authors' Addresses
Sheng Jiang Sheng Jiang (editor)
Huawei Technologies Huawei Technologies
Q14, Huawei Campus, No.156, BeiQing Road Q14, Huawei Campus, No.156, BeiQing Road
Hai-Dian District, Beijing 100095 Hai-Dian District, Beijing 100095
P.R. China P.R. China
Email: jiangsheng@huawei.com Email: jiangsheng@huawei.com
Frank Xia Frank Xia
Huawei Technologies Huawei Technologies
1700 Alma Dr. Suite 500 1700 Alma Dr. Suite 500
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