draft-ietf-softwire-ds-lite-tunnel-option-02.txt   draft-ietf-softwire-ds-lite-tunnel-option-03.txt 
Softwires D. Hankins Softwires D. Hankins
Internet-Draft ISC Internet-Draft ISC
Intended status: Standards Track T. Mrugalski Intended status: Standards Track T. Mrugalski
Expires: September 3, 2010 Gdansk University of Technology Expires: December 26, 2010 Gdansk University of Technology
March 2, 2010 June 24, 2010
Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Options for Dual- Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Options for Dual-
Stack Lite Stack Lite
draft-ietf-softwire-ds-lite-tunnel-option-02 draft-ietf-softwire-ds-lite-tunnel-option-03
Abstract Abstract
This document specifies two DHCPv6 options which are meant to be used This document specifies two DHCPv6 options which are meant to be used
by a Dual-Stack Lite client (Basic Bridging BroadBand element, B4) to by a Dual-Stack Lite client (Basic Bridging BroadBand element, B4) to
discover its Address Family Transition Router (AFTR) address. discover its Address Family Transition Router (AFTR) address.
Status of this Memo Status of this Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Requirements Language . . . . . . . . . . . . . . . . . . . . . 3 1. Requirements Language . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. The Dual-Stack Lite Address DHCPv6 Option . . . . . . . . . . . 3 3. The Dual-Stack Lite Address DHCPv6 Option . . . . . . . . . . . 3
4. The Dual-Stack Lite Name DHCPv6 Option . . . . . . . . . . . . 4 4. The Dual-Stack Lite Name DHCPv6 Option . . . . . . . . . . . . 4
5. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . . 6 5. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . . 6
6. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . . 7 6. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
10. Normative References . . . . . . . . . . . . . . . . . . . . . 8 10. Normative References . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Requirements Language 1. Requirements Language
In this document, the key words "MAY", "MUST", "MUST NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"OPTIONAL", "RECOMMENDED", "SHOULD", and "SHOULD NOT", are to be "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
interpreted as described in BCP 14, RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
2. Introduction 2. Introduction
Dual-Stack Lite [I-D.softwire-ds-lite-03] is a solution to offer both Dual-Stack Lite [I-D.softwire-ds-lite-04] is a solution to offer both
IPv4 and IPv6 connectivity to customers which are addressed only with IPv4 and IPv6 connectivity to customers which are addressed only with
an IPv6 prefix (no IPv4 address is assigned to the attachment an IPv6 prefix (no IPv4 address is assigned to the attachment
device). One of its key components is an IPv4-over-IPv6 tunnel, device). One of its key components is an IPv4-over-IPv6 tunnel,
commonly referred to as a Softwire, but a DS-Lite Basic Bridging commonly referred to as a Softwire, but a DS-Lite Basic Bridging
BroadBand (B4) will not know if the network it is attached to offers BroadBand (B4) will not know if the network it is attached to offers
Dual-Stack Lite support, and if it did would not know the remote end Dual-Stack Lite support, and if it did would not know the remote end
of the tunnel to establish a connection. of the tunnel to establish a connection.
To inform the B4 of the AFTR's location, either an IPv6 address or To inform the B4 of the AFTR's location, either an IPv6 address or
Fully Qualified Domain Name (FQDN) may be used. Once this Fully Qualified Domain Name (FQDN) may be used. Once this
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The client validates the DS-Lite Address option by confirming the The client validates the DS-Lite Address option by confirming the
option is of 16 octets in length or greater. The client MUST ignore option is of 16 octets in length or greater. The client MUST ignore
any tunnel-endpoint-addr shorter than 16 octets. In the event the any tunnel-endpoint-addr shorter than 16 octets. In the event the
option is greater than 16 octets in length, only the first 16 octets option is greater than 16 octets in length, only the first 16 octets
are interpreted. are interpreted.
Because this option conveys the tunnel-endpoint-addr value, no Because this option conveys the tunnel-endpoint-addr value, no
further processing is required of the client. further processing is required of the client.
This option conveys a single IPv6 address, as the Dual-Stack Lite This option conveys a single IPv6 address, as the Dual-Stack Lite
specification [I-D.softwire-ds-lite-03] defines only one Softwire specification [I-D.softwire-ds-lite-04] defines only one Softwire
connection between a B4 and any AFTR. Multiple connections or connection between a B4 and any AFTR. Multiple connections or
endpoints are undefined. For more information, see Section 7.2 "High endpoints are undefined. For more information, see Section 7.2 "High
Availability" of [I-D.softwire-ds-lite-03]. Availability" of [I-D.softwire-ds-lite-04].
4. The Dual-Stack Lite Name DHCPv6 Option 4. The Dual-Stack Lite Name DHCPv6 Option
The Dual-Stack Lite Name option consists of option-code and option- The Dual-Stack Lite Name option consists of option-code and option-
len fields (common for all DHCPv6 options), and a variable length len fields (common for all DHCPv6 options), and a variable length
tunnel-endpoint-name field, containing a Fully Qualified Domain Name tunnel-endpoint-name field, containing a Fully Qualified Domain Name
that refers to the AFTR the client is requested to establish a that refers to the AFTR the client is requested to establish a
connection with. connection with.
The DS-Lite Name option MAY appear in the root scope of a DHCPv6 The DS-Lite Name option MAY appear in the root scope of a DHCPv6
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endpoint-name is of valid format as described in DHCPv6 Section 8 endpoint-name is of valid format as described in DHCPv6 Section 8
[RFC3315]; there are no compression tags, there is at least one label [RFC3315]; there are no compression tags, there is at least one label
of nonzero length. of nonzero length.
The client (B4) determines a value for the tunnel-endpoint-addr from The client (B4) determines a value for the tunnel-endpoint-addr from
the tunnel-endpoint-name using standard DNS resolution, as defined in the tunnel-endpoint-name using standard DNS resolution, as defined in
[RFC3596]. If the DNS response contains more than one IPv6 address, [RFC3596]. If the DNS response contains more than one IPv6 address,
the client picks only one IPv6 address and uses it as a remote tunnel the client picks only one IPv6 address and uses it as a remote tunnel
endpoint. The client MUST NOT establish more than one DS-Lite tunnel endpoint. The client MUST NOT establish more than one DS-Lite tunnel
at the same time. For a redundancy and high availability discussion, at the same time. For a redundancy and high availability discussion,
see Section 7.2 "High availability" of [I-D.softwire-ds-lite-03]. see Section 7.2 "High availability" of [I-D.softwire-ds-lite-04].
5. DHCPv6 Server Behavior 5. DHCPv6 Server Behavior
DHCP servers must translate user input from their own specific and DHCP servers must translate user input from their own specific and
unique operator's interfaces into configuration state for the client. unique operator's interfaces into configuration state for the client.
The server MUST provide a way to configure the OPTION_DS_LITE_ADDR, The server MUST provide a way to configure the OPTION_DS_LITE_ADDR,
and SHOULD allow the operator to enter a Fully Qualified Domain Name, and SHOULD allow the operator to enter a Fully Qualified Domain Name,
upon which the server performs DNS Resolution to assemble its upon which the server performs DNS Resolution to assemble its
OPTION_DS_LITE_ADDR contents. The server MAY either provide the same OPTION_DS_LITE_ADDR contents. The server MAY either provide the same
Fully Qualified Domain Name as OPTION_DS_LITE_NAME contents, or Fully Qualified Domain Name as OPTION_DS_LITE_NAME contents, or
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If OPTION_DS_LITE_NAME is being configured, the server MUST be If OPTION_DS_LITE_NAME is being configured, the server MUST be
configured to provide OPTION_DNS_SERVERS defined in [RFC3646] configured to provide OPTION_DNS_SERVERS defined in [RFC3646]
together with the DS-Lite Name option, so that clients will be able together with the DS-Lite Name option, so that clients will be able
to ask for DNS servers locations to resolve the domain name provided to ask for DNS servers locations to resolve the domain name provided
in the DS-Lite Name option. in the DS-Lite Name option.
6. DHCPv6 Client Behavior 6. DHCPv6 Client Behavior
A client that supports B4 functionality of DS-Lite (defined in A client that supports B4 functionality of DS-Lite (defined in
[I-D.softwire-ds-lite-03]) MUST include OPTION_DS_LITE_ADDR on its [I-D.softwire-ds-lite-04]) MUST include OPTION_DS_LITE_ADDR on its
OPTION_ORO, and MAY include OPTION_DS_LITE_NAME at its option and OPTION_ORO, and MAY include OPTION_DS_LITE_NAME at its option and
ability. ability.
If requesting the OPTION_DS_LITE_NAME option, the client also SHOULD If requesting the OPTION_DS_LITE_NAME option, the client also SHOULD
request OPTION_DNS_SERVERS defined in [RFC3646] to be able to resolve request OPTION_DNS_SERVERS defined in [RFC3646] to be able to resolve
any received domain name. any received domain name.
If the client receives either DS-Lite option, it MUST verify the If the client receives either DS-Lite option, it MUST verify the
option contents as described in Section 3 and Section 4. The client option contents as described in Section 3 and Section 4. The client
(B4) SHOULD establish a softwire tunnel to the tunnel-endpoint-addr (B4) SHOULD establish a softwire tunnel to the tunnel-endpoint-addr
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This document does not present any new security issues, but as with This document does not present any new security issues, but as with
all DHCPv6-derived configuration state, it is completely possible all DHCPv6-derived configuration state, it is completely possible
that the configuration is being delivered by a third party (Man In that the configuration is being delivered by a third party (Man In
The Middle). As such, there is no basis to trust that the access the The Middle). As such, there is no basis to trust that the access the
DS-Lite Softwire connection represents can be trusted, and it should DS-Lite Softwire connection represents can be trusted, and it should
not therefore bypass any security mechanisms such as IP firewalls. not therefore bypass any security mechanisms such as IP firewalls.
RFC 3315 [RFC3315] discusses DHCPv6-related security issues. RFC 3315 [RFC3315] discusses DHCPv6-related security issues.
[I-D.softwire-ds-lite-03] discusses DS-Lite related security issues. [I-D.softwire-ds-lite-04] discusses DS-Lite related security issues.
8. IANA Considerations 8. IANA Considerations
IANA is requested to allocate two DHCPv6 option codes referencing IANA is requested to allocate two DHCPv6 option codes referencing
this document. One delineating OPTION_DS_LITE_ADDR, and one this document. One delineating OPTION_DS_LITE_ADDR, and one
delineating OPTION_DS_LITE_NAME. delineating OPTION_DS_LITE_NAME.
9. Acknowledgements 9. Acknowledgements
Authors would like to thank Alain Durand, Rob Austein, Dave Thaler Authors would like to thank Alain Durand, Rob Austein, Dave Thaler
and Paul Selkirk for their valuable feedback and suggestions. and Paul Selkirk for their valuable feedback and suggestions.
10. Normative References 10. Normative References
[I-D.softwire-ds-lite-03] [I-D.softwire-ds-lite-04]
Durand, A., Ed., "Dual-stack lite broadband deployments Durand, A., Ed., "Dual-stack lite broadband deployments
post IPv4 exhaustion", post IPv4 exhaustion",
draft-ietf-softwire-dual-stack-lite-03 (work in progress), draft-ietf-softwire-dual-stack-lite-04 (work in progress),
February 2010. March 2010.
[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.
[RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
"DNS Extensions to Support IP Version 6", RFC 3596, "DNS Extensions to Support IP Version 6", RFC 3596,
skipping to change at page 8, line 42 skipping to change at page 8, line 42
950 Charter Street 950 Charter Street
Redwood City, CA 94063 Redwood City, CA 94063
US US
Phone: +1 650 423 1307 Phone: +1 650 423 1307
Email: David_Hankins@isc.org Email: David_Hankins@isc.org
Tomasz Mrugalski Tomasz Mrugalski
Gdansk University of Technology Gdansk University of Technology
Storczykowa 22B/12 Storczykowa 22B/12
Gdansk, 80-177 Gdansk 80-177
Poland Poland
Phone: +48 698 088 272 Phone: +48 698 088 272
Email: tomasz.mrugalski@eti.pg.gda.pl Email: tomasz.mrugalski@eti.pg.gda.pl
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