NETEXT WG S. Gundavelli, Ed. Internet-Draft Cisco Intended status: Standards Track X. Zhou Expires: August 18, 2013 ZTE Corporation J. Korhonen Nokia Siemens Networks G. Feige R. Koodli Cisco February 14, 2013 IPv4 Traffic Offload Selector Option for Proxy Mobile IPv6 draft-ietf-netext-pmipv6-sipto-option-11.txt Abstract This specification defines a new mobility option, IPv4 Traffic Offload Selector option, for Proxy Mobile IPv6. This option can be used by the local mobility anchor and the mobile access gateway for negotiating IPv4 traffic offload policy for a mobility session. Based on the negotiated IPv4 traffic offload policy, a mobile access gateway can selectively offload some of the IPv4 traffic flows in the access network instead of tunneling back to the local mobility anchor in the home network. 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 August 18, 2013. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. Gundavelli, et al. Expires August 18, 2013 [Page 1] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4 2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 3. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 4 3.1. IPv4 Traffic Offload Selector Option . . . . . . . . . . . 7 3.2. MAG Considerations . . . . . . . . . . . . . . . . . . . . 9 3.3. LMA Considerations . . . . . . . . . . . . . . . . . . . . 10 4. Protocol Configuration Variables . . . . . . . . . . . . . . . 12 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 8.1. Normative References . . . . . . . . . . . . . . . . . . . 14 8.2. Informative References . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Gundavelli, et al. Expires August 18, 2013 [Page 2] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 1. Introduction Mobile Operators are expanding their network coverage by integrating various access technology domains (Ex: Wireless LAN, CDMA, LTE) into a common IP mobility core. The 3GPP S2a Proxy Mobile IPv6 [TS23402] reference point, specified by the 3GPP system architecture defines the protocol inter-working for building such integrated multi-access network. In this scenario, the mobile node's IP traffic is always tunneled back from the mobile access gateway [RFC5213] in the access network to the local mobility anchor in the home network. Currently, there is no mechanism for allowing some of the subscriber's IP flows to be offloaded in the access network. With the exponential growth in the mobile data traffic, mobile operators are exploring new ways to offload some of the IP traffic flows at the nearest access edge. The offload is intended either for local service access in the access network, or for internet offload through the access network when there is an internet peering point. Not all IP traffic flows needs to be routed back to the home network, some of the non-essential traffic which does not require IP mobility support can be offloaded at the mobile access gateway in the access network. This approach allows efficient usage of the mobile packet core which helps in lowering transport costs. The local mobility anchor in the home network can deliver the IP flow policy to the mobile access gateway in the access network, for identifying the IP flows that need to be offloaded. It's a policy decision as to which traffic an operator deems as non-essential. One operator might choose to offload everything except traffic (such as Voice over IP) that requires QoS services. Another might choose to offload only HTTP traffic. From the point of view of this specification, it is only about IP traffic matching a given flow selector and classification for offload. This approach has one limitation with respect to identifying encrypted traffic: IPsec encrypted traffic with no visibility into the application payload cannot be selected for offload. This document defines a new mobility option, IPv4 Traffic Offload Selector option (Section 3.1) for Proxy Mobile IPv6 (PMIPv6). This option can be used by the local mobility anchor for delivering the IPv4 traffic offload policy associated with a mobility session to the mobile access gateway. This IPv4 traffic offload policy identifies the flow selectors that can used for selecting the flows for offloading them at the access edge. Since, the mobile node's IP address topologically belongs to the home network, the offloaded IPv4 traffic flows may need to be NAT [RFC2663] translated. These offloaded flows will not have mobility support as the NAT becomes the anchor point for those flows. However, when the traffic is offloaded for local service access as opposed to internet offload, NAT Gundavelli, et al. Expires August 18, 2013 [Page 3] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 translation may not be needed, if the mobile access gateways is in path for the return traffic. The decision on when to apply NAT translation can be based on local configuration on the mobile access gateway. There are better ways to address the offload problem for IPv6 and with the goal not to create NAT66 requirement, this specification therefore does not support traffic offload support for IPv6 flows. 2. Conventions and Terminology 2.1. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 2.2. Terminology All the mobility related terms used in this document are to be interpreted as defined in the base Proxy Mobile IPv6 specifications [RFC5213] and [RFC5844]. Additionally, this document uses the following terms: IP Flow IP Flow [RFC5101] represents a set of IP packets that match a traffic selector. The selector is typically based on the source IP address, destination IP address, source port, destination port and other fields in upper layer headers. IP Traffic Offload The approach of selecting specific IP flows and routing them through the access network, instead of tunneling them to the home network. Offload can also be between two access networks (Example: moving some of the traffic from LTE access to WLAN access). 3. Solution Overview Figure 1 illustrates the scenario where the mobile access gateway in an access network has enabled IPv4 traffic offload support for a mobility session. The offload decision is based on the IPv4 traffic offload policy that it negotiated with the local mobility anchor in the home network. For example, all the HTTP flows may be offloaded at the mobile access gateway and all the other flows for that Gundavelli, et al. Expires August 18, 2013 [Page 4] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 mobility session are tunneled back to the local mobility anchor. The offloaded flows have to be typically NAT translated and this specification does not impose any restrictions on the location of the NAT function. It is possible for the NAT function to be co-located with the mobile access gateway or located somewhere in the edge of the access network. When the NAT function is not co-located with the mobile access gateway, offloaded traffic flows must be delivered through the local access network between the mobile access gateway and the NAT function, for example through a VLAN or a point-to-point link. The exact means for this delivery are outside the scope of this document. If the offloaded IPv4 flows are for local service access and reverse traffic from the local service device can be routed to the mobile node through the mobile access gateway, the offloaded flows may be delivered directly to local service device. The traffic selectors in the IPv4 traffic offload policy are used to classify the traffic, so it can be offloaded to the access network. These parameters include Source IP address, Destination IP address, TCP/UDP Port numbers, and other fields. The format of the IPv4 Binary Traffic Selector is specified in section 3.1 of [RFC6088]. Gundavelli, et al. Expires August 18, 2013 [Page 5] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 _----_ _( )_ :-----------------( Internet )---------------: | (_ _) | | '----' | | | : | (IPv4 Traffic Offload Point) | : | | | ........................................................|.... | | | +--------+ | +---------------------+ | | Local | | | Services requiring | | |Services| | | mobility, or service| | +--------+ | | treatment | | | | +---------------------+ | | +---+ | | | |NAT| | | | +---+ | | +-----| _----_ | | +-----+ _( )_ +-----+ | [MN]----| MAG |======( IP )======| LMA |---------- +-----+ (_ _) +-----+ Internet '----' . . [Access Network] . [Home Network] .......................................................... Figure 1: IPv4 Traffic Offload Support at the MAG Figure 2 explains the operational sequence of the Proxy Mobile IPv6 protocol signaling message exchange between the mobile access gateway and the local mobility anchor for negotiating the IPv4 Traffic Offload selectors. The details related to DHCP transactions, or Router Advertisements on the access link are not shown here as that is not the key focus of this specification. The use of IPv4 Traffic Selector option in the Proxy Binding Update is for allowing the MAG to request the LMA for the IPv4 Traffic Offload policy. Gundavelli, et al. Expires August 18, 2013 [Page 6] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 MN MAG(NAT) LMA |------>| | 1. Mobile Node Attach | |------->| 2. Proxy Binding Update (IPv4TS) | |<-------| 3. Proxy Binding Acknowledgement (IPv4TS) | |========| 4. Tunnel/Route Setup | + | 5. Installing the traffic offload rules |------>| | 6. IPv4 packet from mobile node | + | 7. Offload rule applied (Tunnel/offload) | | | Figure 2: Exchange of IPv4 Traffic Offload Selectors 3.1. IPv4 Traffic Offload Selector Option A new mobility option, IPv4 Traffic Offload Selector option, is defined for using it in Proxy Binding Update (PBU) and Proxy Binding Acknowledgement (PBA) messages exchanged between a mobile access gateway and a local mobility anchor. This option is used for carrying the IPv4 traffic offload policy. This policy identifies the IPv4 traffic flow selectors that can be used by the mobile access gateway for enforcing the offload policy. The alignment requirement for this option is 4n. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |M| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Traffic Selector Sub-option ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: IPv4 Traffic Offload Selector Option Type Length 8-bit unsigned integer indicating the length in octets of the option, excluding the type and length fields. Gundavelli, et al. Expires August 18, 2013 [Page 7] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 Offload Mode (M) Flag This field indicates the offload mode. If the (M) flag value is set to a value of (0), it is an indication that the IPv4 flow(s) matching the traffic selectors in the Traffic Selector sub-option [RFC6089] and that are associated to that mobility session have to be offloaded at the mobile access gateway. All the other IPv4 flows associated with that mobility session and not matching the traffic selectors have to be tunneled to the local mobility anchor. If the (M) flag value is set to a value of (1), it is an indication that all the IPv4 flows associated to that mobility session except the IPv4 flow(s) matching the traffic selectors in the Traffic Selector sub-option have to be offloaded at the mobile access gateway. All the other IPv4 flows associated with that mobility session and not matching the traffic selectors have to be tunneled back to the local mobility anchor. Reserved This field is unused for now. The value MUST be initialized to 0 by the sender and MUST be ignored by the receiver. Traffic Selector Sub-option The traffic selector sub-option includes the parameters used to match packets for a specific flow binding. This is an optional sub-option when the IPv4 Traffic Selector option is carried in a Proxy Binding Update message, but is a mandatory sub-option when the IPv4 Traffic Selector option is carried in a Proxy Binding Acknowledgement message. The format of the Traffic Selector sub- option is defined in section 4.2.1.4 of [RFC6089]. This sub- option includes a TS Format field, which identifies the format of the flow specification included in that sub-option. The values for that field are defined in section 3 of [RFC6088] and are repeated here for completeness. When the value of TS Format field is set to (1), the format that follows is the IPv4 Binary Traffic Selector specified in section 3.1 of [RFC6088] and that support is mandatory for this specification. The text specified in this section takes precedence over what is specified in [RFC6088] and [RFC6089]. 1: IPv4 binary traffic selector. 2: IPv6 binary traffic selector (Not used by this specification) Gundavelli, et al. Expires August 18, 2013 [Page 8] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 3.2. MAG Considerations o If the mobile access gateway is configured to support IPv4 Traffic Offload support, then it includes the IPv4 Traffic Offload Selector option (Section 3.1) in the Proxy Binding Update message that it sends to the local mobility anchor. Optionally, the mobile access gateway can also propose a specific offload policy. * The mobile access gateway MAY choose not to propose any specific IPv4 traffic offload policy but request the local mobility anchor for the offload policy. In this scenario, the IPv4 Traffic Offload Selector option that is carried in the Proxy Binding Update message does not include the Traffic Selector sub-option (Section 3.1) and the (M) flag Section 3.1 in the option MUST be set to value of (0). Including the IPv4 Traffic Offload Selector option in the Proxy Binding Update without the Traffic Selector Sub-option serves as an indication that the mobile access gateway is not proposing any specific offload policy for that mobility session, but rather it makes a request to the local mobility anchor to provide the offload policy. * The mobile access gateway MAY choose to propose a specific IPv4 traffic offload policy by including the Traffic Selector sub- option in the IPv4 Traffic Offload Selector option Section 3.1. The specific details on how the mobile access gateway obtains the mobile node's IPv4 traffic offload policy, is outside the scope of this document. When this offload policy is included in the Proxy Binding Update message, it serves as a proposal to the local mobility anchor, which the local mobility anchor can override with its own offload policy, or agree to the proposed policy. The offload policy has to be translated to a set of selectors that can be used to match the mobile node's IP flows and these selectors have to be carried in the Traffic Selector Sub-option. The Traffic Selector sub-option MUST be constructed as specified section 4.2.1.4 of [RFC6089]. This sub-option includes a Traffic Selector Format field, which identifies the format of the flow specification included in that sub-option. The values for that field and the corresponding message format are defined in section 3.0 of [RFC6088]. Considerations from Section 3.1 apply with respect to setting the Offload Mode (M) flag. o When sending a Proxy Binding Update either for Binding lifetime extension, or for Binding De-Registration, the mobile access gateway SHOULD copy the IPv4 Traffic Offload Selector option from the initial Proxy Binding Update message. Considerations from section 6.9.1.3 [RFC5213] and section 6.9.1.4 [RFC5213] MUST be Gundavelli, et al. Expires August 18, 2013 [Page 9] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 applied. o If the mobile access gateway is not configured to support IPv4 traffic offload support as specified in this specification, but if the received Proxy Binding Acknowledgement message has the IPv4 Traffic Offload Selector option, then the mobile access gateway MUST ignore the option and process the rest of the message as per [RFC5213]. o If there is no IPv4 Traffic Offload Selector option in the Proxy Binding Acknowledgement message received from the local mobility anchor, it is indication that the local mobility anchor did not enable IPv4 Traffic Offload support for that mobility session. The mobile access gateway upon accepting the Proxy Binding Acknowledgement message SHOULD NOT enable IPv4 traffic offload support for that mobility session. o If there is an IPv4 Traffic Offload Selector option in the Proxy Binding Acknowledgement message, then the mobile access gateway SHOULD enable the IPv4 traffic offload support for that mobility session. The mobility access gateway has to provision the data plane using the flow selectors present in the Traffic Selector Sub-option. The IPv4 flows matching the flow selectors have to be offloaded, or tunneled back based to the local mobility anchor based on the value of the Offload Mode (M) flag Section 3.1. 3.3. LMA Considerations o If the received Proxy Binding Update message does not include the IPv4 Traffic Offload Selector option (Section 3.1), then the local mobility anchor MUST NOT enable IPv4 Traffic Offload support for that mobility session and the Proxy Binding Acknowledgement message that will be sent in response MUST NOT contain the IPv4 Traffic Offload Selector option. o If the Proxy Binding Update message includes the IPv4 Traffic Offload Selector option, but the local mobility anchor is not configured to support IPv4 Traffic Offload support, then the local mobility anchor will ignore the option and process the rest of the message as per [RFC5213]. This would have no effect on the operation of the rest of the protocol. o If the Proxy Binding Update message has the IPv4 Traffic Offload Selector option and if the local mobility anchor is configured to support IPv4 Traffic Offload support, then the local mobility anchor MUST enable IPv4 Traffic Offload support for that mobility session. The Proxy Binding Acknowledgement message that will be sent in response MUST include the IPv4 Traffic Offload Selector Gundavelli, et al. Expires August 18, 2013 [Page 10] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 option. The following considerations apply with respect to constructing the IPv4 Traffic Offload Selector option. * The local mobility anchor can obtain the offload policy from the local configuration store, or from a network function such as from AAA (Authentication, Authorization and Accounting), or PCRF (Policy Charging and Rules Function)). The offload policy has to be translated to a set of selectors that can be used to match the mobile node's IP flows and these selectors have to be carried in the Traffic Selector Sub-option. The Traffic Selection Sub-option MUST be constructed as specified in section 4.2.1.4 of [RFC6089]. Considerations from Section 3.1 apply with respect to Offload Mode Flag (M) setting. * If the Proxy Binding Update message includes a specific IPv4 Traffic Offload policy proposal in the form of Traffic Selector Sub-option [RFC6089], then the local mobility anchor MAY choose to agree to that request by including the same IPv4 Traffic Offload policy in the Proxy Binding Acknowledgement message. This implies the local mobility anchor has agreed to the mobile access gateway provided IPv4 Traffic Offload policy. The local mobility anchor MAY also choose to override the request by including a different IPv4 Traffic Offload policy that it wants the mobile access gateway to enforce for that mobility session. This is entirely based on the policy configuration on the local mobility anchor. * The IPv4 traffic offload policy that is sent to the mobile access gateway has to be specific to the mobility session identified using the Mobile Node Identifier option [RFC5213]. The offload policy MUST be specific to a mobile node's application traffic. The traffic selectors have to match only the mobile node's application traffic and MUST NOT match any other mobile node's IP traffic. Furthermore, control plane traffic such as DHCP, ND or any other IP traffic that is used for IP address configuration, mobility management or for other control plane functions has to be excluded. * The local mobility anchor MUST NOT make any changes to the mobile node's offload policy during the middle of a mobility session, as that might break some of the IP sessions. Therefore the IPv4 Traffic Selector option with the Traffic Selector sub-option that is delivered during the initial mobility signaling signaling MUST be the same as the one that is delivered as part of the mobility signaling related to lifetime extension. Gundavelli, et al. Expires August 18, 2013 [Page 11] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 4. Protocol Configuration Variables This specification defines the following configuration variable that controls the IPv4 Traffic Offload support feature. This configuration variable is internal to the system and has no bearing on interoperability across different implementations. The mobility entities, local mobility anchor and the mobile access gateway have to allow these variables to be configured by the system management. The configured values for these protocol variables have to survive server reboots and service restarts. EnableIPv4TrafficOffloadSupport This flag indicates whether or not IPv4 Traffic Offload support needs to be enabled. This configuration variable is available at both in the mobile access gateway and at the local mobility anchor. The default value for this flag is set to (0), indicating that the support for IPv4 Traffic offload support is disabled. When this flag on the mobile access gateway is set to a value of (1), the mobile access gateway has to enable the IPv4 Traffic offload support for all mobility sessions, specifically request the IPv4 traffic offload policy from the local mobility anchor by including the IPv4 Traffic Offload Selector option in the Proxy Binding Update message. If the flag is set to a value of (0), the mobile access gateway has to disable support for IPv4 Traffic Offload support for all mobility sessions. Similarly, when this flag on the local mobility anchor is set to a value of (1), the local mobility anchor has to enable support for IPv4 Traffic offload support. When the local mobility anchor chooses to enable IPv4 Traffic offload support and if there is offload policy specified for a mobile node, it has to deliver the IPv4 traffic offload policy to the mobile access gateway by including the IPv4 Traffic Offload Selector option in the Proxy Binding Acknowledgement message. 5. IANA Considerations This document requires the following IANA action. o Action-1: This specification defines a new mobility option, IPv4 Traffic Offload Selector option. This option is described in Section 3.1. The Type value for this option needs to be assigned from the same numbering space as allocated for the other mobility Gundavelli, et al. Expires August 18, 2013 [Page 12] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 options [RFC6275]. o RFC Editor: Please replace in Section 4 with the assigned value, and update this section accordingly. 6. Security Considerations The IPv4 Traffic Offload Selector option defined in this specification is for use in Proxy Binding Update and Proxy Binding Acknowledgement messages. This option is carried like any other mobility header option as specified in [RFC5213]. Therefore it inherits from [RFC5213] its security guidelines and does not require any additional security considerations. Carrying IPv4 traffic offload selectors does not introduce any new security vulnerabilities. When IPv4 traffic offload support is enabled for a mobile node, the mobile access gateway selectively offloads some of the mobile node's IPv4 traffic flows to the access network. Typically, these offloaded flows get NAT translated and essentially that introduces certain vulnerabilities which are common to any NAT deployment. These vulnerabilities and the related considerations have been well documented in the NAT specification [RFC2663]. There are no additional considerations above and beyond what has already been documented by the NAT specifications and which are unique to the approach specified in this document. The mobile node's home network may be equipped with firewall and other security devices to guard against any security threats. When IPv4 traffic offload support is enabled, it potentially exposes the mobile node to some security risks in the access network. This threat can be mitigated by deploying the security features in the access network as in the home network. When IPv4 traffic offload support is enabled for a mobile node, some of the IP flows are sent through the home network and some other IP flows are routed through the access network. This potentially introduces some complexity with respect to enabling diagnostics or monitoring on the user traffic. The tools that are used for such diagnostics have to be aware of the offload policy that in enabled in the network. 7. Acknowledgements The authors would like to thank Ahmad Muhanna, Basavaraj Patil, Carlos Bernardos, Eric Voit, Frank Brockners, Hidetoshi Yokota, Marco Gundavelli, et al. Expires August 18, 2013 [Page 13] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 Liebsch, Mark Grayson, Pierrick Seite, Ryuji Wakikawa, Steve Wood, Barry Lieba, Sean Turner, Pete Resnick, Wesley Eddy, Mary Barnes, Vincent Roca, Ralph Droms, Scott Bradner, Stephen Farrell, Adrian Farrell, Benoit Claise and Brian Haberman for all the draft reviews and discussions related to the topic of IPv4 traffic offload. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. [RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy Mobile IPv6", RFC 5844, May 2010. [RFC6088] Tsirtsis, G., Giarreta, G., Soliman, H., and N. Montavont, "Traffic Selectors for Flow Bindings", RFC 6088, January 2011. [RFC6089] Tsirtsis, G., Soliman, H., Montavont, N., Giaretta, G., and K. Kuladinithi, "Flow Bindings in Mobile IPv6 and Network Mobility (NEMO) Basic Support", RFC 6089, January 2011. [RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, July 2011. 8.2. Informative References [RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address Translator (NAT) Terminology and Considerations", RFC 2663, August 1999. [RFC5101] Claise, B., "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information", RFC 5101, January 2008. [TS23402] 3GPP, "Architecture enhancements for non-3GPP accesses", 2010. Gundavelli, et al. Expires August 18, 2013 [Page 14] Internet-Draft IPv4 Traffic Offload Selector Option February 2013 Authors' Addresses Sri Gundavelli (editor) Cisco 170 West Tasman Drive San Jose, CA 95134 USA Email: sgundave@cisco.com Xingyue Zhou ZTE Corporation No.68 Zijinghua Rd Nanjing China Email: zhou.xingyue@zte.com.cn Jouni Korhonen Nokia Siemens Networks Linnoitustie 6 Espoo FIN-02600 Finland Email: jouni.nospam@gmail.com Gaetan Cisco France Email: gfeige@cisco.com Rajeev Koodli Cisco 3650 Cisco Way San Jose, CA 95134 USA Email: rkoodli@cisco.com Gundavelli, et al. Expires August 18, 2013 [Page 15]