draft-ietf-v6ops-64share-00.txt   draft-ietf-v6ops-64share-01.txt 
V6OPS Working Group C. Byrne V6OPS Working Group C. Byrne
Internet-Draft T-Mobile USA Internet-Draft T-Mobile USA
Intended Status: Informational D. Drown Intended Status: Informational D. Drown
Expires: June 17, 2013 December 14, 2012 Expires: August 2, 2013 January 29, 2013
Sharing /64 3GPP Mobile Interface Subnet to a LAN Extending an IPv6 /64 Prefix from a 3GPP Mobile Interface to a LAN
draft-ietf-v6ops-64share-00 draft-ietf-v6ops-64share-01
Abstract Abstract
This document describes a known and implemented method of sharing a This document describes three methods for extending an IPv6 /64
/64 IPv6 prefix from a User Equipment 3GPP radio interface to a prefix from a User Equipment 3GPP radio interface to a LAN.
tethered LAN.
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 and License Notice Copyright and License Notice
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V6OPS Working Group draft-ietf-v6ops-64share-00 December 14, 2012 V6OPS Working Group draft-ietf-v6ops-64share-01 January 29, 2013
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The Challenge of Providing IPv6 Addresses to a 3GPP Tethered 2. The Challenge of Providing IPv6 Addresses to a LAN via a 3GPP
UE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Methods for Extending the 3GPP Interface /64 IPv6 Prefix to a
LAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 LAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Method for Sharing the 3GPP Interface /64 to the Tethered LAN . 3 3.0 General Behavior for All Scenarios . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 3.1 Scenario 1: No Global Address on the UE . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 3.2 Scenario 2: Global Address Only Assigned to LAN . . . . . . 5
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 3.3 Scenario 3: A Single Global Address Assigned to 3GPP Radio
7. Informative References . . . . . . . . . . . . . . . . . . . . 5 and LAN Interface . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Informative References . . . . . . . . . . . . . . . . . . . . 7
V6OPS Working Group draft-ietf-v6ops-64share-00 December 14, 2012 V6OPS Working Group draft-ietf-v6ops-64share-01 January 29, 2013
1. Introduction 1. Introduction
3GPP mobile cellular networks such as GSM, UMTS, and LTE have 3GPP mobile cellular networks such as GSM, UMTS, and LTE have
architectural support for IPv6 [RFC6459], but only 3GPP Release-10 architectural support for IPv6 [RFC6459], but only 3GPP Release-10
and onwards of the 3GPP specification supports DHCPv6 [RFC3633] for and onwards of the 3GPP specification supports DHCPv6 Prefix
delegating IPv6 addresses to a tethered LAN. To facilitate the use Delegation [RFC3633] for delegating IPv6 prefixes to a LAN. To
of IPv6 in a tethered LAN prior to deployment of DHCPv6 in a 3GPP facilitate the use of IPv6 in a LAN prior to deployment of DHCPv6
network and in User Equipment (UE), this document describes how the Prefix Delegation in 3GPP networks and in User Equipment (UE), this
3GPP UE interface assigned /64 subnet may be shared from the 3GPP document describes how the 3GPP UE interface assigned global /64
interface to a tethered LAN. This is achieved by specifying the UE prefix may be extended from the 3GPP radio interface to a LAN. This
3GPP interface as an IPv6 /128 subnet taken from the 3GPP interface's is achieved by receiving the Router Advertisement (RA) [RFC4861]
network assigned /64 subnet. Then, assign the same address to the announced globally unique /64 IPv6 prefix from the 3GPP radio
tethered LAN interface with the full /64 subnet. The /64 tethered interface and then advertise the same IPv6 prefix to the LAN with RA.
LAN subnet will then be advertised to the tethered LAN via Router
Advertisements (RA) [RFC4861].
The end result is that all UE interfaces have link-local IPv6 This document describes three methods for achieving IPv6 prefix
addresses, the UE's 3GPP interface has a /128 address from the 3GPP extension from a 3GPP radio interface to a LAN including: 1) The 3GPP
network assigned /64, and the same address that is assigned to the UE does not have a global scope IPv6 address on any interface, only
3GPP interface is assigned to the tethered LAN interface with a /64 link-local IPv6 addresses are present on the UE 2) The 3GPP UE only
subnet and advertised to the LAN via RA. This approach only impacts has a global scope address on the LAN interface 3) The 3GPP UE
the UE configuration and does not require any changes to the 3GPP maintains the same consistent 128 bit global scope IPv6 anycast
network. address [RFC4291] on the 3GPP radio interface and the LAN interface.
The LAN interface is configured as a /64 and the 3GPP radio interface
is configured as a /128.
2. The Challenge of Providing IPv6 Addresses to a 3GPP Tethered LAN Section 3 describes the characteristics of each of the three
approaches.
As described in [RFC6459], 3GPP networks assign a /64 subnet to each 2. The Challenge of Providing IPv6 Addresses to a LAN via a 3GPP UE
UE with RA. IPv6 prefix delegation is an optional part of 3GPP
Release-10 and is not covered by any earlier releases. Neighbor
Discovery Proxy (ND Proxy) [RFC4389] functionality has been suggested
as an option for sharing the assigned /64 from the 3GPP interface to
the LAN, but ND Proxy is an experimental protocol and has some
limitations with loop-avoidance.
DHCPv6 is the best way to delegate a prefix to a tethered LAN. The As described in [RFC6459], 3GPP networks assign a /64 global scope
method described in this document should only be applied when prefix to each UE using RA. DHCPv6 Prefix Delegation is an optional
deploying DHCPv6 is not achievable in the 3GPP network and the UE. part of 3GPP Release-10 and is not covered by any earlier releases.
Neighbor Discovery Proxy (ND Proxy) [RFC4389] functionality has been
suggested as an option for extending the assigned /64 from the 3GPP
interface to the LAN, but ND Proxy is an experimental protocol and
has some limitations with loop-avoidance.
3. Method for Sharing the 3GPP Interface /64 to the Tethered LAN DHCPv6 is the best way to delegate a prefix to a LAN. The methods
described in this document should only be applied when deploying
DHCPv6 Prefix Delegation is not achievable in the 3GPP network and
the UE.
3. Methods for Extending the 3GPP Interface /64 IPv6 Prefix to a LAN
3.0 General Behavior for All Scenarios
As [RFC6459] describes, the 3GPP network assigned /64 is completely As [RFC6459] describes, the 3GPP network assigned /64 is completely
dedicated to the UE and the gateway does not consume any of the /64 dedicated to the UE and the gateway does not consume any of the /64
V6OPS Working Group draft-ietf-v6ops-64share-01 January 29, 2013
addresses. The gateway routes the entire /64 to the UE and does not addresses. The gateway routes the entire /64 to the UE and does not
perform ND or Network Unreachability Detection (NUD) [RFC4861]. perform ND or Network Unreachability Detection (NUD) [RFC4861].
Communication between the UE and the gateway is only done using link- Communication between the UE and the gateway is only done using link-
local addresses and the link is point-to-point. This allows for the local addresses and the link is point-to-point. This allows for the
UE to use the 3GPP network assigned /64 to assign itself a /128 UE to reliably manipulate the /64 from the 3GPP radio interface
without negatively impacting the point-to-point 3GPP radio link
V6OPS Working Group draft-ietf-v6ops-64share-00 December 14, 2012 interface. The LAN interface RA configuration must be tightly
address to the 3GPP radio interface for consistent network connection
formation and the same address with a /64 to the tethered LAN
interface. The tethered LAN interface may then advertise the /64 to
the LAN with RA. The LAN interface RA configuration must be tightly
coupled with the 3GPP interface state. If the 3GPP interface goes coupled with the 3GPP interface state. If the 3GPP interface goes
down or changes address, that state should be reflected in the LAN down or changes address, that state should be reflected in the LAN
IPv6 configuration. Just as in a standard IPv6 router, the packet IPv6 configuration. Just as in a standard IPv6 router, the packet
TTL will be decremented when passing packets between interfaces. TTL will be decremented when passing packets between interfaces
across the UE.
The procedure may also be described in terms of the following usage 3.1 Scenario 1: No Global Address on the UE
example:
1. The user activates tethering on the wireless LAN of the UE. In this case, the UE receives the /64 from the 3GPP network via RA
and simply configures Neighbor Discovery Protocol (NDP) [RFC4861] on
the LAN interface to announce the /64 via RA. The 3GPP UE does not
assign itself any global IPv6 addresses. The UE cannot originate or
terminate any global scope packets in this case since it does not
have a global scope IPv6 address to source or receive packets. The
LAN attached devices have complete access to the /64, but the 3GPP UE
only has link-local addresses.
2. The UE checks to make sure the 3GPP interfaces is active and has This method is appropriate for a use-case where the UE is effectively
an IPv6 router that does not require any global connectivity. No
global connectivity will prevent proper Path MTU Discovery [RFC1981]
Below is the general procedure for this scenario:
1. The user activates router functionality for a LAN on the UE.
2. The UE checks to make sure the 3GPP interface is active and has
an IPv6 address. If the interface does not have an IPv6 address, an IPv6 address. If the interface does not have an IPv6 address,
an attempt will be made to acquire one, or else the procedure an attempt will be made to acquire one, or else the procedure
will terminate. will terminate.
3. In this example, the UE finds the 3GPP interface has the IPv6 3. In this example, the UE finds the 3GPP interface has the IPv6
address 2001:db8:ac10:f002:1234:4567:0:9/128 assigned and active. address 2001:db8:ac10:f002:1234:4567:0:9/64 assigned and active.
4. The UE copies the address 2001:db8:ac10:f002:1234:4567:0:9 with a 4. The UE copies the prefix 2001:db8:ac10:f002::/64 from the 3GPP
64 bit mask from the 3GPP interfaces to the wireless LAN interface to the LAN interface, removes the global IPv6 address
interfaces and begins announcing the prefix configuration from the 3GPP radio interface, and begins
2001:db8:ac10:f002::/64 via RA to the wireless LAN. announcing the global prefix 2001:db8:ac10:f002::/64 via RA to
the LAN. The 3GPP interface and LAN interface only maintain
link-local addresses while the UE uses RA to announce the /64 to
the LAN.
5. The gateway in the 3GPP network routes all packets for V6OPS Working Group draft-ietf-v6ops-64share-01 January 29, 2013
2001:db8:ac10:f002::/64 to the UE using the link-local address as
the next hop. The gateway does not perform Neighbor Discover or
Network Unreachability Detection on 3GPP wireless link segment
towards the UE.
6. The UE directly processes all packets destine to itself at 5. Since the UE and gateway do not assign any of the addresses from
the /64, there is no chance of an address conflict on the 3GPP
radio interface. On the LAN interface, there is no chance of an
address conflict since the hosts on the LAN will use Duplicate
Address Detection (DAD) [RFC4862].
3.2 Scenario 2: Global Address Only Assigned to LAN
For this case, the UE receives the RA from the 3GPP network but does
not use a global address on the 3GPP interface. The 3GPP RA /64
prefix information is used to configure NDP on the LAN and assigns
itself an address on the LAN link. The LAN interface use RA to
announces the prefix to the LAN. The UE LAN interface defends its
LAN IPv6 address with DAD.
This method allows the UE to originate and terminate IPv6
communications as a host while acting as an IPv6 router. The
movement of the IPv6 prefix from the 3GPP radio interface to the LAN
interface may result in long-lived data connections being terminated
during the transition from a host-only mode to router-and-host mode.
This method is appropriate if the UE or software on the UE cannot
support multiple interfaces with the same anycast IPv6 address and
the UE requires global connectivity while acting as a router.
Below is the general procedure for this scenario:
1. The user activates router functionality for a LAN on the UE.
2. The UE checks to make sure the 3GPP interfaces is active and has
an IPv6 address. If the interface does not have an IPv6 address,
an attempt will be made to acquire one, or else the procedure
will terminate.
3. In this example, the UE finds the 3GPP interface has the IPv6
address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active.
4. The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as a
/64 from the 3GPP interfaces to the LAN interface and begins
announcing the prefix 2001:db8:ac10:f002::/64 via RA to the LAN.
For this example, the LAN has 2001:db8:ac10:f002:1234:4567:0:9/64
and the 3GPP radio only has a link-local address.
5. The UE directly processes all packets destine to itself at
2001:db8:ac10:f002:1234:4567:0:9. 2001:db8:ac10:f002:1234:4567:0:9.
7. The UE, acting as a router running NDP on the LAN, will route 6. The UE, acting as a router running NDP on the LAN, will route
V6OPS Working Group draft-ietf-v6ops-64share-01 January 29, 2013
packet to and from the LAN. IPv6 packets passing between packet to and from the LAN. IPv6 packets passing between
interfaces will have the TTL decremented. interfaces will have the TTL decremented.
8. If the 3GPP interface state changes, the LAN will immediately 7. On the LAN interface, there is no chance of address conflict
update to reflect the change and ensure that the LAN IPv6 prefix since the address is defended using DAD. The 3GPP radio
remains a valid extension of the 3GPP network. interface only has link-local addresses.
9. Since the address 2001:db8:ac10:f002:1234:4567:0:9/128 is the 3.3 Scenario 3: A Single Global Address Assigned to 3GPP Radio and LAN
only instance of the assigned /64 on the 3GPP interface, there is Interface
no chance of an address conflict on that interface. On the LAN
interface, there is no chance of address conflict since the
V6OPS Working Group draft-ietf-v6ops-64share-00 December 14, 2012 In this method, the UE assigns itself one address from the 3GPP
network RA announced /64. This one address is configured as anycast
[RFC4291] on both the 3GPP radio interface as a /128 and on the LAN
interface as a /64. This allows the UE to maintain long lived data
connections since the 3GPP radio interface address does not change
when the router function is activated. This method may cause
complications for certain software that may not support multiple
interfaces with the same anycast IPv6 address. This method also
creates complications for ensuring uniqueness for Privacy Extensions
[RFC4941]. Privacy Extensions should be disabled on the 3GPP radio
interface while this method is enabled.
address is defended using Duplicate Address Detection (DAD). Below is the general procedure for this scenario:
The UE should be compliant with the relevant requirements in [I- 1. The user activates router functionality for a LAN on the UE.
D.draft-binet-v6ops-cellular-host-requirement].
2. The UE checks to make sure the 3GPP interfaces is active and has
an IPv6 address. If the interface does not have an IPv6 address,
an attempt will be made to acquire one, or else the procedure
will terminate.
3. In this example, the UE finds the 3GPP interface has the IPv6
address 2001:db8:ac10:f002:1234:4567:0:9 assigned and active.
4. The UE moves the address 2001:db8:ac10:f002:1234:4567:0:9 as an
anycast /64 from the 3GPP interface to the LAN interface and
begins announcing the prefix 2001:db8:ac10:f002::/64 via RA to
the LAN. The 3GPP interface maintains the same IPv6 anycast
address with a /128. For this example, the LAN has
2001:db8:ac10:f002:1234:4567:0:9/64 and the 3GPP radio interface
has 2001:db8:ac10:f002:1234:4567:0:9/128.
5. The UE directly processes all packets destine to itself at
2001:db8:ac10:f002:1234:4567:0:9.
6. On the LAN interface, there is no chance of address conflict
since the address is defended using DAD. The 3GPP radio
V6OPS Working Group draft-ietf-v6ops-64share-01 January 29, 2013
interface only has a /128 and no other systems on the 3GPP radio
point-to-point link may use the global /64.
4. Security Considerations 4. Security Considerations
Security considerations identified in [I-D.draft-binet-v6ops- Security considerations identified in [I-D.draft-ietf-v6ops-
cellular-host-requirement] are to be taken into account. rfc3316bis] are to be taken into account. Since Scenario 3 does not
allow for Privacy Extension to run the 3GPP interface, UEs that
require this functionality must find an alternative method.
5. IANA Considerations 5. IANA Considerations
This document does not require any action from IANA. This document does not require any action from IANA.
6. Acknowledgments 6. Acknowledgments
Many thanks for review and discussion from Masanobu Kawashima, Teemu Many thanks for review and discussion from Mark Smith, Dmitry Anipko,
Savolainen, Mikael Abrahamsson, Eric Vyncke, Alexandru Petrescu, Masanobu Kawashima, Teemu Savolainen, Mikael Abrahamsson, Eric
Jouni Korhonen, Julien Laganier, and Ales Vizdal. Vyncke, Alexandru Petrescu, Jouni Korhonen, Julien Laganier, and Ales
Vizdal.
7. Informative References 7. Informative References
[I-D.draft-binet-v6ops-cellular-host-requirement] Binet, D., [I-D.ietf-v6ops-rfc3316bis] Korhonen, J., Arkko, J., Savolainen, T.,
Boucadair, M., A. Vizdal, C. Byrne, G. Chen, "Internet and S. Krishnan, "IPv6 for 3GPP Cellular Hosts", draft-
Protocol Version 6 (IPv6) for Cellular Hosts", draft- ietf-v6ops-rfc3316bis (work in progress), November 2012.
draft-binet-v6ops-cellular-host-requirement (work in
progress), October 2012. [RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery
for IP version 6", RFC 1981, August 1996.
[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.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery [RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery
Proxies (ND Proxy)", RFC 4389, April 2006. Proxies (ND Proxy)", RFC 4389, April 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.
V6OPS Working Group draft-ietf-v6ops-64share-01 January 29, 2013
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007.
[RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen, [RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen,
T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
Partnership Project (3GPP) Evolved Packet System (EPS)", Partnership Project (3GPP) Evolved Packet System (EPS)",
RFC 6459, January 2012. RFC 6459, January 2012.
Authors' Addresses Authors' Addresses
V6OPS Working Group draft-ietf-v6ops-64share-00 December 14, 2012
Cameron Byrne Cameron Byrne
T-Mobile USA T-Mobile USA
Bellevue, Washington, USA Bellevue, Washington, USA
EMail: Cameron.Byrne@T-Mobile.com EMail: Cameron.Byrne@T-Mobile.com
Dan Drown Dan Drown
Email: Dan@Drown.org Email: Dan@Drown.org
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