Sharing /64 3GPP Mobile Interface Subnet to a LAN
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This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|Authors||Cameron Byrne , Dan Drown|
|Replaced by||draft-ietf-v6ops-64share, draft-ietf-v6ops-64share, RFC 7278|
|Stream||Stream state||(No stream defined)|
|RFC Editor Note||(None)|
|IESG||IESG state||I-D Exists|
|Send notices to||(None)|
V6OPS Working Group C. Byrne Internet-Draft T-Mobile USA Intended Status: Informational Dan Drown Expires: April 1, 2013 September 28, 2012 Sharing /64 3GPP Mobile Interface Subnet to a LAN draft-byrne-v6ops-64share-00 Abstract This document describes a known and implemented method of sharing a /64 IPv6 subnet from a 3GPP interface to a tethered LAN. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 1, 2013. Copyright and License Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Byrne Expires April 1, 2013 [Page 1] V6OPS Working Group draft-byrne-v6ops-64share-00 September 28, 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The Challenge of Providing IPv6 Addresses to a 3GPP Tethered LAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Method for Sharing the 3GPP Interface /64 to the Tethered LAN . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 4 7. Informative References . . . . . . . . . . . . . . . . . . . . 4 Byrne Expires April 1, 2013 [Page 2] V6OPS Working Group draft-byrne-v6ops-64share-00 September 28, 2012 1. Introduction 3GPP mobile cellular networks such as GSM, UMTS, and LTE have architectural support for IPv6 [RFC6459], but only 3GPP Release-10 and onwards of the 3GPP standard supports DHCPv6 [RFC3633] for delegating IPv6 addresses to a tethered LAN. To facilitate the use of IPv6 in a tethered LAN prior to deployment of DHCPv6 in a 3GPP network, this document describes how the 3GPP User Equipment (UE) interface assigned /64 subnet may be shared from the 3GPP interface to a tethered LAN. This is achieved by specifying the 3GPP interface as an IPv6 /128 subnet taken from the 3GPP interface's network assigned /64 subnet. Then, assign the same address to the tethered LAN interface with the full /64 subnet. The /64 tethered LAN subnet will then be advertised to the tethered LAN via Router Advertisements (RA) [RFC4861]. The end result is that all interfaces have link-local IPv6 addresses, the 3GPP interface has a /128 address from the 3GPP network assigned /64, and the same address that is assigned to the 3GPP interface is assigned to the tethered LAN interface with a /64 subnet and advertised to the LAN via RA. 2. The Challenge of Providing IPv6 Addresses to a 3GPP Tethered LAN As described in [RFC6459], 3GPP networks assigns a /64 subnet to the UE with RA. IPv6 prefix delegation is a 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 and other complexities that prevent it from being broadly applied. DHCPv6 is the best way to assign subnets to tethered LANs. The method described in this document should only be applied when deploying DHCPv6 is not achievable in the 3GPP network. 3. Method for Sharing the 3GPP Interface /64 to the Tethered LAN As [RFC6459] describes, the 3GPP network assigned /64 is completely dedicated to the UE and the gateway does not consume any of the /64 addresses. 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 UE to use the 3GPP network assigned /64 to assign itself a /128 subnet address to the 3GPP interface for consistent network reachability and the same address with a /64 subnet to the tethered LAN interface. The tethered LAN interface may then Byrne Expires April 1, 2013 [Page 3] V6OPS Working Group draft-byrne-v6ops-64share-00 September 28, 2012 advertise the /64 subnet to the LAN with RA. For example, if the 3GPP network assigns to the UE via RA the subnet 2001:0DB8:AC10:F002::/64, the UE may choose the address for its 3GPP interface to be 2001:DB80:AC10:F002:1234:4567::9/128. When tethering a LAN, the UE may then assign that same address to its LAN with a /64 subnet, such as 2001:DB80:AC10:F002:1234:4567::9/64. The UE may then advertise the 2001:DB80:AC10:F002::/64 subnet to the tethered LAN using RA. Since the UE only consumes one address from the 3GPP network assigned /64 for both the 3GPP interface and the LAN interface, there is no address conflict potential. On the LAN, the /64 subnet is announced via RA and the interface address is defended with Duplicate Address Detection (DAD) [RFC4862]. Since the 3GPP interface is a point-to-point link and the gateway does not consume an address from the network assigned /64, there is no chance of conflict on the 3GPP interface for the /64. For completeness, while tethering a LAN the UE should provide [RFC6204] LAN-Side configuration support. Additionally, it may be beneficial to advertise the MTU of 1440 bytes via RA to the LAN to avoid fragmentation within the 3GPP network infrastructure. 4. Security Considerations The LAN features may be compliant with security requirements specified in [RFC6092] 5. IANA Considerations This document does not require any action from IANA. 6. Acknowledgments TBD 7. Informative References [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host Configuration Protocol (DHCP) version 6", RFC 3633, December 2003. [RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery Proxies (ND Proxy)", RFC 4389, April 2006. [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, September 2007. Byrne Expires April 1, 2013 [Page 4] V6OPS Working Group draft-byrne-v6ops-64share-00 September 28, 2012 [RFC6092] Woodyatt, J., Ed., "Recommended Simple Security Capabilities in Customer Premises Equipment (CPE) for Providing Residential IPv6 Internet Service", RFC 6092, January 2011. [RFC6459] Korhonen, J., Soininen, J., Patil, B., Savolainen, T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation Partnership Project (3GPP) Evolved Packet System (EPS)", RFC 6459, January 2012. Authors' Addresses Cameron Byrne T-Mobile USA Bellevue, Washington, USA EMail: Cameron.Byrne@T-Mobile.com Dan Drown Email: Dan@Drown.org Byrne Expires April 1, 2013 [Page 5]