draft-ietf-6man-addr-select-opt-05.txt | draft-ietf-6man-addr-select-opt-06.txt | |||
---|---|---|---|---|
6man Working Group A. Matsumoto | 6man Working Group A. Matsumoto | |||
Internet-Draft T. Fujisaki | Internet-Draft T. Fujisaki | |||
Intended status: Standards Track NTT | Intended status: Standards Track NTT | |||
Expires: February 24, 2013 T. Chown | Expires: March 25, 2013 T. Chown | |||
University of Southampton | University of Southampton | |||
August 23, 2012 | September 21, 2012 | |||
Distributing Address Selection Policy using DHCPv6 | Distributing Address Selection Policy using DHCPv6 | |||
draft-ietf-6man-addr-select-opt-05.txt | draft-ietf-6man-addr-select-opt-06.txt | |||
Abstract | Abstract | |||
RFC 3484 defines default address selection mechanisms for IPv6 that | RFC 6724 defines default address selection mechanisms for IPv6 that | |||
allow nodes to select appropriate address when faced with multiple | allow nodes to select appropriate address when faced with multiple | |||
source and/or destination addresses to choose between. The RFC 3484 | source and/or destination addresses to choose between. The RFC 6724 | |||
allowed for the future definition of methods to administratively | allowed for the future definition of methods to administratively | |||
configure the address selection policy information. This document | configure the address selection policy information. This document | |||
defines a new DHCPv6 option for such configuration, allowing a site | defines a new DHCPv6 option for such configuration, allowing a site | |||
administrator to distribute address selection policy overriding the | administrator to distribute address selection policy overriding the | |||
default address selection parameters and policy table, and thus | default address selection parameters and policy table, and thus | |||
control the address selection behavior of nodes in their site. | control the address selection behavior of nodes in their site. | |||
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 | |||
skipping to change at page 1, line 40 | skipping to change at page 1, line 40 | |||
Internet-Drafts are working documents of the Internet Engineering | Internet-Drafts are working documents of the Internet Engineering | |||
Task Force (IETF). Note that other groups may also distribute | Task Force (IETF). Note that other groups may also distribute | |||
working documents as Internet-Drafts. The list of current Internet- | working documents as Internet-Drafts. The list of current Internet- | |||
Drafts is at http://datatracker.ietf.org/drafts/current/. | Drafts is at http://datatracker.ietf.org/drafts/current/. | |||
Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
time. It is inappropriate to use Internet-Drafts as reference | time. It is inappropriate to use Internet-Drafts as reference | |||
material or to cite them other than as "work in progress." | material or to cite them other than as "work in progress." | |||
This Internet-Draft will expire on February 24, 2013. | This Internet-Draft will expire on March 25, 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 | |||
document authors. All rights reserved. | document authors. All rights reserved. | |||
This document is subject to BCP 78 and the IETF Trust's Legal | This document is subject to BCP 78 and the IETF Trust's Legal | |||
Provisions Relating to IETF Documents | Provisions Relating to IETF Documents | |||
(http://trustee.ietf.org/license-info) in effect on the date of | (http://trustee.ietf.org/license-info) in effect on the date of | |||
publication of this document. Please review these documents | publication of this document. Please review these documents | |||
skipping to change at page 2, line 28 | skipping to change at page 2, line 28 | |||
outside the IETF Standards Process, and derivative works of it may | outside the IETF Standards Process, and derivative works of it may | |||
not be created outside the IETF Standards Process, except to format | not be created outside the IETF Standards Process, except to format | |||
it for publication as an RFC or to translate it into languages other | it for publication as an RFC or to translate it into languages other | |||
than English. | than English. | |||
1. Introduction | 1. Introduction | |||
RFC 3484 [RFC3484] describes default algorithms for selecting an | RFC 3484 [RFC3484] describes default algorithms for selecting an | |||
address when a node has multiple destination and/or source addresses | address when a node has multiple destination and/or source addresses | |||
to choose from by using an address selection policy. In Section 2 of | to choose from by using an address selection policy. In Section 2 of | |||
RFC 3484, it is suggested that the default policy table may be | RFC 6724, it is suggested that the default policy table may be | |||
administratively configured to suit the specific needs of a site. | administratively configured to suit the specific needs of a site. | |||
This specification defines a new DHCPv6 option for such | This specification defines a new DHCPv6 option for such | |||
configuration. | configuration. | |||
Some problems have been identified with the default RFC 3484 address | Some problems have been identified with the default RFC 3484 address | |||
selection policy [RFC5220]. It is unlikely that any default policy | selection policy [RFC5220]. It is unlikely that any default policy | |||
will suit all scenarios, and thus mechanisms to control the source | will suit all scenarios, and thus mechanisms to control the source | |||
address selection policy will be necessary. Requirements for those | address selection policy will be necessary. Requirements for those | |||
mechanisms are described in [RFC5221], while solutions are discussed | mechanisms are described in [RFC5221], while solutions are discussed | |||
in [I-D.ietf-6man-addr-select-sol] and | in [I-D.ietf-6man-addr-select-sol] and | |||
[I-D.ietf-6man-addr-select-considerations]. Those documents have | [I-D.ietf-6man-addr-select-considerations]. Those documents have | |||
helped shape the improvements in the default address selection | helped shape the improvements in the default address selection | |||
algorithm [I-D.ietf-6man-rfc3484bis] as well as the DHCPv6 option | algorithm [RFC6724] as well as the DHCPv6 option defined in this | |||
defined in this specification. | specification. | |||
1.1. Conventions Used in This Document | 1.1. Conventions Used in This Document | |||
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]. | |||
1.2. Terminology | 1.2. Terminology | |||
This document uses the terminology defined in [RFC2460] and the | This document uses the terminology defined in [RFC2460] and the | |||
skipping to change at page 3, line 44 | skipping to change at page 3, line 44 | |||
option-code: OPTION_ADDRSEL (TBD). | option-code: OPTION_ADDRSEL (TBD). | |||
option-len: The total length of the Reserved field, A, P flags, and | option-len: The total length of the Reserved field, A, P flags, and | |||
POLICY TABLE OPITONS in octets. | POLICY TABLE OPITONS in octets. | |||
Reserved: Reserved field. Server MUST set this value to zero and | Reserved: Reserved field. Server MUST set this value to zero and | |||
client MUST ignore its content. | client MUST ignore its content. | |||
A: Automatic Row Addition flag. This flag toggles the Automatic | A: Automatic Row Addition flag. This flag toggles the Automatic | |||
Row Addition flag at client hosts, which is described in the | Row Addition flag at client hosts, which is described in the | |||
section 2.1 in RFC 3484 revision [I-D.ietf-6man-rfc3484bis]. If | section 2.1 in RFC 6724 [RFC6724]. If this flag is set to 1, it | |||
this flag is set to 1, it does not change client host behavior, | does not change client host behavior, that is, a client MAY | |||
that is, a client MAY automatically add additional site-specific | automatically add additional site-specific rows to the policy | |||
rows to the policy table. If set to 0, the Automatic Row | table. If set to 0, the Automatic Row Addition flag is | |||
Addition flag is disabled, and a client MAY NOT automatically | disabled, and a client MAY NOT automatically add rows to the | |||
add rows to the policy table. | policy table. | |||
P: Privacy Preference flag. This flag toggles the Privacy | P: Privacy Preference flag. This flag toggles the Privacy | |||
Preference flag at client hosts, which is described in the | Preference flag at client hosts, which is described in the | |||
section 5 in RFC 3484 revision [I-D.ietf-6man-rfc3484bis]. If | section 5 in RFC 6724 [RFC6724]. If this flag is set to 1, it | |||
this flag is set to 1, it does not change client host behavior, | does not change client host behavior, that is, a client SHOULD | |||
that is, a client SHOULD prefer temporary addresses. If set to | prefer temporary addresses. If set to 0, the Privacy Preference | |||
0, the Privacy Preference flag is disabled, and a client SHOULD | flag is disabled, and a client SHOULD prefer public addresses. | |||
prefer public addresses. | ||||
POLICY TABLE OPTIONS: Zero or more Address Selection Policy Table | POLICY TABLE OPTIONS: Zero or more Address Selection Policy Table | |||
options described below. | options described below. | |||
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 | |||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |||
| OPTION_ADDRSEL_TABLE | option-len | | | OPTION_ADDRSEL_TABLE | option-len | | |||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |||
| label | precedence | prefix-len | | | | label | precedence | prefix-len | | | |||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | |||
| | | | | | |||
| prefix (variable length) | | | prefix (variable length) | | |||
| | | | | | |||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |||
| | | ||||
. Prefix Specific options . | ||||
. . | ||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ||||
Figure 2: Address Selection Policy Table option format | Figure 2: Address Selection Policy Table option format | |||
option-code: OPTION_ADDRSEL_TABLE (TBD). | option-code: OPTION_ADDRSEL_TABLE (TBD). | |||
option-len: The total length of the label field, precedence field, | option-len: The total length of the label field, precedence field, | |||
prefix-len field, prefix field, and DASP options field in | prefix-len field, and prefix field. | |||
octets. | ||||
label: An 8-bit unsigned integer; this value is used to make a | label: An 8-bit unsigned integer; this value is for correlation of | |||
combination of source address prefixes and destination address | source address prefixes and destination address prefixes. | |||
prefixes. | ||||
precedence: An 8-bit unsigned integer; this value is used for | precedence: An 8-bit unsigned integer; this value is used for | |||
sorting destination addresses. | sorting destination addresses. | |||
prefix-len: An 8-bit unsigned integer; the number of leading bits in | prefix-len: An 8-bit unsigned integer; the number of leading bits in | |||
the prefix that are valid. The value ranges from 0 to 128. | the prefix that are valid. The value ranges from 0 to 128. | |||
prefix: A variable-length field containing an IP address or the | prefix: A variable-length field containing an IP address or the | |||
prefix of an IP address. An IPv4-mapped address [RFC4291] must | prefix of an IP address. An IPv4-mapped address [RFC4291] must | |||
be used to represent an IPv4 address as a prefix value. The | be used to represent an IPv4 address as a prefix value. The | |||
Prefix should be truncated on the byte boundary. So the length | prefix should be zero padded up to the next octet boundary. So | |||
of this field should be between 0 and 16 bytes. | the length of this field should be between 0 and 16 bytes. | |||
Prefix Specific options: Options specific to this particular Address | ||||
Selection Policy option. This includes, but not limited to, | ||||
zero or one Zone Index option that specify the zone index of the | ||||
prefix in this option. | ||||
The format of the Zone Index option is given below. | ||||
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 | ||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ||||
| OPTION_ADDRSEL_ZONE | option-len | | ||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ||||
| zone-index | | ||||
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ||||
Figure 3: Zone Index option format | ||||
option-code: OPTION_ADDRSEL_ZONE (TBD). | ||||
option-len: 4. | ||||
zone-index: The zone-index field is an 32-bit unsigned integer, and | ||||
used to specify the zone for scoped addresses. The zone-index | ||||
is defined in RFC 3493 [RFC3493] as 'scope ID'. | ||||
3. Appearance of the Address Selection options | 3. Appearance of the Address Selection options | |||
The Address Selection options MUST NOT appear in any messages other | The Address Selection options MUST NOT appear in any messages other | |||
than the following ones: Solicit, Advertise, Request, Renew, Rebind, | than the following ones: Solicit, Advertise, Request, Renew, Rebind, | |||
Reconfigure, Information-Request, and Reply. | Reconfigure, Information-Request, and Reply. | |||
4. Processing the Policy Table option | 4. Processing the Policy Table option | |||
This section describes how to process received Policy Table option at | This section describes how to process received Policy Table option at | |||
the DHCPv6 client. | the DHCPv6 client. | |||
This option's concept is to serve as a hint for a node about how to | This option's concept is to serve as a hint for a node about how to | |||
behave in the network. So, basically, it should be up to the node's | behave in the network. So, basically, it should be up to the node's | |||
administrator how to deal with the received policy information in the | administrator how to deal with the received policy information in the | |||
way described below. | way described below. | |||
4.1. Handling of the local policy table | 4.1. Handling of the local policy table | |||
RFC 3484 defines the default policy table. Also, a user is usually | RFC 6724 defines the default policy table. Also, a user is usually | |||
able to configure the policy table to satisfy his requirement. | able to configure the policy table to satisfy his requirement. | |||
The client implementation SHOULD provide the following choices to the | The client implementation SHOULD provide the following choices to the | |||
user: | user: | |||
a) It receives distributed policy table, and replaces the existing | a) It receives distributed policy table, and replaces the existing | |||
policy tables with that. | policy tables with that. | |||
b) It preserves the default policy table, or manually configured | b) It preserves the default policy table, or manually configured | |||
policy. | policy. | |||
skipping to change at page 6, line 38 | skipping to change at page 5, line 48 | |||
policy should be restored. | policy should be restored. | |||
The received information can be considered stale in several cases, | The received information can be considered stale in several cases, | |||
such as, when the interface goes down, the DHCP server does not | such as, when the interface goes down, the DHCP server does not | |||
respond for a certain amount of time, and the Information Refresh | respond for a certain amount of time, and the Information Refresh | |||
Time is expired. | Time is expired. | |||
4.3. Multi-interface situation | 4.3. Multi-interface situation | |||
The policy table, and other parameters specified in this document are | The policy table, and other parameters specified in this document are | |||
node-global information by its nature. So, the node cannot use | node-global information by its nature. One of the reason is that the | |||
multiple received policies at the same time. In other words, once | outbound interface is usually chosen after destination address | |||
the received policy from one source is merged with one from another | selection. So, a host cannot make use of multiple address selection | |||
source, the effect of both policy are more or less changed. The | policy even if they are stored per interface. | |||
policy table is defined as a whole, so the slightest addition/ | ||||
Even if the received policy from one source is merged with one from | ||||
another source, the effect of both policy are more or less changed. | ||||
The policy table is defined as a whole, so the slightest addition/ | ||||
deletion from the policy table brings a change in semantics of the | deletion from the policy table brings a change in semantics of the | |||
policy. | policy. | |||
It also should be noted that absence of the distributed policy from a | It also should be noted that absence of the distributed policy from a | |||
certain network interface should not be treated as absence of policy | certain network interface should not be treated as absence of policy | |||
itself, because it may mean preference for the default address | itself, because it may mean preference for the default address | |||
selection policy. | selection policy. | |||
Under the above assumptions, how to handle received policy is | Under the above assumptions, how to handle received policy is | |||
specified below. | specified below. | |||
skipping to change at page 7, line 19 | skipping to change at page 6, line 32 | |||
1: The host is single-homed, where the host belongs to one | 1: The host is single-homed, where the host belongs to one | |||
administrative network domain exclusively usually through one | administrative network domain exclusively usually through one | |||
active network interface. | active network interface. | |||
2: The host implements some advanced heuristics to deal with multiple | 2: The host implements some advanced heuristics to deal with multiple | |||
received policy, which is outside the scope of this document. | received policy, which is outside the scope of this document. | |||
The above restrictions do not preclude implementations from providing | The above restrictions do not preclude implementations from providing | |||
configuration options to enable this option on a certain network | configuration options to enable this option on a certain network | |||
interface. | interface. | |||
Nor, they do not preclude implementations from storing distributed | ||||
address selection policies per interface. They can be used | ||||
effectively on such implementations that adopt per-application | ||||
interface selection. | ||||
5. Implementation Considerations | 5. Implementation Considerations | |||
o The value 'label' is passed as an unsigned integer, but there is | o The value 'label' is passed as an unsigned integer, but there is | |||
no special meaning for the value, that is whether it is a large or | no special meaning for the value, that is whether it is a large or | |||
small number. It is used to select a preferred source address | small number. It is used to select a preferred source address | |||
prefix corresponding to a destination address prefix by matching | prefix corresponding to a destination address prefix by matching | |||
the same label value within the DHCP message. DHCPv6 clients need | the same label value within the DHCP message. DHCPv6 clients need | |||
to convert this label to a representation specified by each | to convert this label to a representation specified by each | |||
implementation (e.g., string). | implementation (e.g., string). | |||
skipping to change at page 8, line 14 | skipping to change at page 7, line 31 | |||
a client. This might lead to incorrect address selection by the | a client. This might lead to incorrect address selection by the | |||
client, and the affected packets might be blocked at an outgoing ISP | client, and the affected packets might be blocked at an outgoing ISP | |||
because of ingress filtering. Alternatively, an IPv6 transition | because of ingress filtering. Alternatively, an IPv6 transition | |||
mechanism might be preferred over native IPv6, even if it is | mechanism might be preferred over native IPv6, even if it is | |||
available. To guard against such attacks, a legitimate DHCPv6 server | available. To guard against such attacks, a legitimate DHCPv6 server | |||
should be communicated through a secure, trusted channel, such as a | should be communicated through a secure, trusted channel, such as a | |||
channel protected by IPsec, SEND and DHCP authentication, as | channel protected by IPsec, SEND and DHCP authentication, as | |||
described in section 21 of RFC 3315, | described in section 21 of RFC 3315, | |||
Another threat is about privacy concern. As in the security | Another threat is about privacy concern. As in the security | |||
consideration section of RFC 3484, at least a part of, the address | consideration section of RFC 6724, at least a part of, the address | |||
selection policy stored in a host can be leaked by a packet from a | selection policy stored in a host can be leaked by a packet from a | |||
remote host. This issue will not be degraded regardless of the | remote host. This issue will not be degraded regardless of the | |||
introduction of this option, or regardless of whether the host is | introduction of this option, or regardless of whether the host is | |||
multihomed or not. | multihomed or not. | |||
7. IANA Considerations | 7. IANA Considerations | |||
IANA is requested to assign option codes to OPTION_ADDRSEL , | IANA is requested to assign option codes to OPTION_ADDRSEL , | |||
OPTION_ADDRSEL_TABLE, and OPTION_ADDRSEL_ZONE from the option-code | OPTION_ADDRSEL_TABLE, and OPTION_ADDRSEL_ZONE from the option-code | |||
space as defined in section "DHCPv6 Options" of RFC 3315. | space as defined in section "DHCPv6 Options" of RFC 3315. | |||
8. References | 8. References | |||
8.1. Normative References | 8.1. Normative References | |||
[I-D.ietf-6man-rfc3484bis] | ||||
Thaler, D., Draves, R., Matsumoto, A., and T. Chown, | ||||
"Default Address Selection for Internet Protocol version 6 | ||||
(IPv6)", draft-ietf-6man-rfc3484bis-06 (work in progress), | ||||
June 2012. | ||||
[I-D.ietf-6man-stable-privacy-addresses] | [I-D.ietf-6man-stable-privacy-addresses] | |||
Gont, F., "A method for Generating Stable Privacy-Enhanced | Gont, F., "A method for Generating Stable Privacy-Enhanced | |||
Addresses with IPv6 Stateless Address Autoconfiguration | Addresses with IPv6 Stateless Address Autoconfiguration | |||
(SLAAC)", draft-ietf-6man-stable-privacy-addresses-00 | (SLAAC)", draft-ietf-6man-stable-privacy-addresses-00 | |||
(work in progress), May 2012. | (work in progress), May 2012. | |||
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | |||
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. | |||
[RFC3484] Draves, R., "Default Address Selection for Internet | [RFC3484] Draves, R., "Default Address Selection for Internet | |||
Protocol version 6 (IPv6)", RFC 3484, February 2003. | Protocol version 6 (IPv6)", RFC 3484, February 2003. | |||
[RFC6724] Thaler, D., Draves, R., Matsumoto, A., and T. Chown, | ||||
"Default Address Selection for Internet Protocol Version 6 | ||||
(IPv6)", RFC 6724, September 2012. | ||||
8.2. Informative References | 8.2. Informative References | |||
[I-D.ietf-6man-addr-select-considerations] | [I-D.ietf-6man-addr-select-considerations] | |||
Chown, T. and A. Matsumoto, "Considerations for IPv6 | Chown, T. and A. Matsumoto, "Considerations for IPv6 | |||
Address Selection Policy Changes", | Address Selection Policy Changes", | |||
draft-ietf-6man-addr-select-considerations-04 (work in | draft-ietf-6man-addr-select-considerations-04 (work in | |||
progress), October 2011. | progress), October 2011. | |||
[I-D.ietf-6man-addr-select-sol] | [I-D.ietf-6man-addr-select-sol] | |||
Matsumoto, A., Fujisaki, T., and R. Hiromi, "Solution | Matsumoto, A., Fujisaki, T., and R. Hiromi, "Solution | |||
skipping to change at page 9, line 43 | skipping to change at page 9, line 11 | |||
[RFC5220] Matsumoto, A., Fujisaki, T., Hiromi, R., and K. Kanayama, | [RFC5220] Matsumoto, A., Fujisaki, T., Hiromi, R., and K. Kanayama, | |||
"Problem Statement for Default Address Selection in Multi- | "Problem Statement for Default Address Selection in Multi- | |||
Prefix Environments: Operational Issues of RFC 3484 | Prefix Environments: Operational Issues of RFC 3484 | |||
Default Rules", RFC 5220, July 2008. | Default Rules", RFC 5220, July 2008. | |||
[RFC5221] Matsumoto, A., Fujisaki, T., Hiromi, R., and K. Kanayama, | [RFC5221] Matsumoto, A., Fujisaki, T., Hiromi, R., and K. Kanayama, | |||
"Requirements for Address Selection Mechanisms", RFC 5221, | "Requirements for Address Selection Mechanisms", RFC 5221, | |||
July 2008. | July 2008. | |||
Appendix A. Past Discussion | Appendix A. Acknowledgements | |||
Authors would like to thank to Dave Thaler, Pekka Savola, Remi Denis- | ||||
Courmont, Francois-Xavier Le Bail, Ole Troan, Bob Hinden, Dmitry | ||||
Anipko, and the members of 6man's address selection design team for | ||||
their invaluable contributions to this document. | ||||
Appendix B. Past Discussion | ||||
o The 'zone index' value is used to specify a particular zone for | o The 'zone index' value is used to specify a particular zone for | |||
scoped addresses. This can be used effectively to control address | scoped addresses. This can be used effectively to control address | |||
selection in the site scope (e.g., to tell a node to use a | selection in the site scope (e.g., to tell a node to use a | |||
specified source address corresponding to a site-scoped multicast | specified source address corresponding to a site-scoped multicast | |||
address). However, in some cases such as a link-local scope | address). However, in some cases such as a link-local scope | |||
address, the value specifying one zone is only meaningful locally | address, the value specifying one zone is only meaningful locally | |||
within that node. There might be some cases where the | within that node. There might be some cases where the | |||
administrator knows which clients are on the network and wants | administrator knows which clients are on the network and wants | |||
specific interfaces to be used though. However, in general case, | specific interfaces to be used though. However, in general case, | |||
it is hard to use this value. | it is really rare case, and the field was removed. | |||
o Since we got a comment that some implementations use 32-bit | ||||
integers for zone index value, we extended the bit length of the | ||||
'zone index' field. However, as described above, there might be | ||||
few cases to specify 'zone index' in policy distribution, we | ||||
defined this field as optional, controlled by a flag. | ||||
o There may be some demands to control the use of special address | ||||
types such as the temporary addresses described in RFC4941 | ||||
[RFC4941], address assigned by DHCPv6 and so on. (e.g., informing | ||||
not to use a temporary address when it communicate within the an | ||||
organization's network). It is possible to indicate the type of | ||||
addresses using reserved field value. | ||||
Authors' Addresses | Authors' Addresses | |||
Arifumi Matsumoto | Arifumi Matsumoto | |||
NTT NT Lab | NTT NT Lab | |||
3-9-11 Midori-Cho | 3-9-11 Midori-Cho | |||
Musashino-shi, Tokyo 180-8585 | Musashino-shi, Tokyo 180-8585 | |||
Japan | Japan | |||
Phone: +81 422 59 3334 | Phone: +81 422 59 3334 | |||
End of changes. 22 change blocks. | ||||
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