Extensible Authentication Protocol (EAP) Attributes for Wi-Fi Integration with the Evolved Packet Core
draft-ietf-netext-wifi-epc-eap-attributes-16
The information below is for an old version of the document that is already published as an RFC.
Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 7458.
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Authors | Ravi Valmikam, Rajeev Koodli | ||
Last updated | 2018-12-20 (Latest revision 2015-01-05) | ||
RFC stream | Internet Engineering Task Force (IETF) | ||
Intended RFC status | Informational | ||
Formats | |||
Reviews |
GENART Telechat review
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-09)
by Peter Yee
Ready w/nits
GENART Last Call review
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by Peter Yee
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Additional resources | Mailing list discussion | ||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Basavaraj Patil | ||
Shepherd write-up | Show Last changed 2014-07-28 | ||
IESG | IESG state | Became RFC 7458 (Informational) | |
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Consensus boilerplate | Unknown | ||
Telechat date | (None) | ||
Responsible AD | Brian Haberman | ||
Send notices to | (None) | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | RFC-Ed-Ack |
draft-ietf-netext-wifi-epc-eap-attributes-16
Netext Ravi. Valmikam Internet-Draft Unaffiliated Intended status: Informational Rajeev. Koodli Expires: July 9, 2015 Intel January 5, 2015 EAP Attributes for Wi-Fi - EPC Integration draft-ietf-netext-wifi-epc-eap-attributes-16 Abstract With Wi-Fi emerging as a crucial access network for mobile service providers, it has become important to provide functions commonly available in 3G and 4G networks in Wi-Fi access networks as well. Such functions include Access Point Name (APN) Selection, multiple Packet Data Network (PDN) connections, and seamless mobility between Wi-Fi and 3G/4G networks. The EAP-AKA (and EAP-AKA') protocol is required for mobile devices to access the mobile Evolved Packet Core (EPC) via Wi-Fi networks. This document defines a few new EAP attributes to enable the above- mentioned functions in such networks. The attributes are exchanged between a client (such as a Mobile Node) and its network counterpart (such as a AAA server) in the service provider's infrastructure. 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 July 9, 2015. Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. Valmikam & Koodli Expires July 9, 2015 [Page 1] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. APN Selection . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Multiple APN Connectivity . . . . . . . . . . . . . . . . 4 1.3. Wi-Fi to E-UTRAN mobility . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Brief Introduction to EAP . . . . . . . . . . . . . . . . 4 3.2. IEEE 802.11 Authentication using EAP over 802.1X . . . . 5 4. New EAP Attributes . . . . . . . . . . . . . . . . . . . . . 7 4.1. APN Selection . . . . . . . . . . . . . . . . . . . . . . 7 4.2. Connectivity Type . . . . . . . . . . . . . . . . . . . . 7 4.3. Wi-Fi to UTRAN/E-UTRAN Mobility . . . . . . . . . . . . . 7 4.4. MN Serial ID . . . . . . . . . . . . . . . . . . . . . . 8 5. Attribute Extensions . . . . . . . . . . . . . . . . . . . . 8 5.1. AT_VIRTUAL_NETWORK_ID . . . . . . . . . . . . . . . . . . 8 5.2. AT_VIRTUAL_NETWORK_REQ . . . . . . . . . . . . . . . . . 9 5.3. AT_CONNECTIVITY_TYPE . . . . . . . . . . . . . . . . . . 10 5.4. AT_HANDOVER_INDICATION . . . . . . . . . . . . . . . . . 11 5.5. AT_HANDOVER_SESSION_ID . . . . . . . . . . . . . . . . . 11 5.6. AT_MN_SERIAL_ID . . . . . . . . . . . . . . . . . . . . . 12 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 8. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 15 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 9.1. Normative References . . . . . . . . . . . . . . . . . . 15 9.2. Informative References . . . . . . . . . . . . . . . . . 16 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 1. Introduction Wi-Fi has emerged as a "trusted" access technology for mobile service providers; see [EPC2] for reference to the 3GPP description of "trusted" access. Advances in IEEE 802.11u [IEEE802.11u] and "HotSpot 2.0" [hs20] have enabled seamless roaming, in which a Mobile Node can select and connect to a Wi-Fi access network just as it Valmikam & Koodli Expires July 9, 2015 [Page 2] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 would roam into a cellular network. It has thus become important to provide certain functions in Wi-Fi which are commonly supported in licensed-spectrum networks such as 3G and 4G networks. This draft specifies a few new EAP attributes for a Mobile Node (MN) to interact with the network to support some of these functions (see below). These new attributes serve as a trigger for Proxy Mobile IPv6 network nodes to undertake the relevant mobility operations. For instance, when the Mobile Node requests and the network agrees for a new IP session (i.e., a new Access Point Name or APN in 3GPP), the corresponding attribute (defined below) acts as a trigger for the Mobile Anchor Gateway (MAG) to initiate a new mobility session with the Local Mobility Anchor (LMA). This document refers to [RFC6459] for the basic definitions of mobile network terminology (such as APN) used here. The 3rd Generation Partnership Project (3GPP) networks support many functions that are not commonly implemented in a Wi-Fi network. This document defines EAP attributes that enable the following functions in Wi-Fi access networks using EAP-AKA' [RFC5448] and EAP-AKA [RFC4187]: o APN Selection o Multiple APN Connectivity o Wi-Fi to 3G/4G (UTRAN/EUTRAN) mobility The attributes defined here are exchanged between the Mobile Node and the EAP server, typically realized as part of the AAA server infrastructure in a service provider's infrastructure. In particular, the Wi-Fi access network simply conveys the attributes to the service provider's core network where the EAP processing takes place [EPC]. Since these attributes share the same IANA registry, the methods are applicable to EAP-AKA', EAP-AKA, EAP-SIM [RFC4186] and, with appropriate extensions, are possibly applicable for other EAP methods as well. In addition to the trusted Wi-Fi access networks, the attributes are applicable to any trusted "non-3GPP" access network that uses the EAP methods and provides connectivity to the mobile EPC, which provides connectivity for 3G, 4G, and other non-3GPP access networks [EPC2]. 1.1. APN Selection The 3GPP networks support the concept of an APN (Access Point Name). This is defined in [GPRS]. Each APN is an independent IP network with its own set of IP services. When the MN attaches to the network, it may select a specific APN to receive desired services. For example, to receive generic Internet services, a user device may Valmikam & Koodli Expires July 9, 2015 [Page 3] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 select APN "Internet" and to receive IMS voice services, it may select APN "IMSvoice". In a Wi-Fi access scenario, an MN needs a way of sending the desired APN name to the network. This draft specifies a new attribute to propagate the APN information via EAP. The agreed APN is necessary for the Proxy Mobile IPv6 MAG to initiate a new session with the LMA. 1.2. Multiple APN Connectivity As an extension of APN Selection, an MN may choose to connect to multiple IP networks simultaneously. 3GPP provides this feature via additional Packet Data Protocol (PDP) contexts or additional Packet Data Network (PDN) connections, and defines the corresponding set of signaling procedures. In a trusted Wi-Fi network, an MN connects to the first APN via DHCPv4 or IPv6 Router Solicitation. This document specifies an attribute that indicates the MN's capability to support multiple APN connectivity. The specific connectivity types are also necessary for the Proxy Mobile IPv6 signaling. 1.3. Wi-Fi to E-UTRAN mobility When operating in a multi-access network, an MN may want to gracefully handover its IP attachment from one access network to another. For instance, an MN connected to a 3GPP E-UTRAN network may choose to move its connectivity to a trusted Wi-Fi network. Alternatively, the MN may choose to connect using both access technologies simultaneously, and maintain two independent IP attachments. To implement these scenarios, the MN needs a way to correlate the UTRAN/E-UTRAN session with the new Wi-Fi session. This draft specifies an attribute to propagate E-UTRAN session identification to the network via EAP. This helps the network to correlate the sessions between the two Radio Access Network technologies and thus helps the overall handover process. 2. Terminology 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 [RFC2119]. 3. Protocol Overview 3.1. Brief Introduction to EAP EAP is defined as a generic protocol in [RFC3748]. EAP, combined with one of the payload protocols such as EAP-AKA' [RFC5448] can accomplish several things in a network: Valmikam & Koodli Expires July 9, 2015 [Page 4] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 o Establish identity of the user (MN) to the network. o Authenticate the user during the first attach with the help of an authentication center that securely maintains the user credentials. This process is called EAP Authentication. o Re-authenticate the user periodically, but without the overhead of a round-trip to the authentication center. This process is called EAP Fast Re-Authentication. This draft makes use of the EAP Authentication procedure. The use of EAP Fast Re-Authentication procedure is for further study. Both the EAP Authentication and EAP Fast Re-Authentication procedures are specified for trusted access network use in 3GPP. [TS-33.402] 3.2. IEEE 802.11 Authentication using EAP over 802.1X In a Wi-Fi network, EAP is carried over the IEEE 802.1X Authentication protocol. The IEEE 802.1X Authentication is a transparent, payload-unaware mechanism to carry the authentication messages between the MN and the Wi-Fi network elements. EAP, on the other hand, has multiple purposes. Apart from its core functions of communicating an MN's credentials to the network and proving the MN's identity, it also allows the MN to send arbitrary information elements to help establish the MN's IP session in the network. The following figure shows an example end-to-end EAP flow in the context of an IEEE 802.11 Wi-Fi network. We first define the terminology: o MN: Mobile Node o WAN: Wi-Fi Access Node, typically consisting of Wi-Fi Access Point and Wi-Fi Controller. In a PMIPv6 [RFC5213] network, the MAG functionality is located in the WAN, either in the Wi-Fi Access Point or in the Wi-Fi Controller. o AAA: The infrastructure node supporting the AAA server with the EAP methods (AKA, AKA', EAP-SIM). The end-points of the EAP method are the MN and the AAA server. o IPCN: IP Core Network. This includes the PMIPv6 LMA function. Valmikam & Koodli Expires July 9, 2015 [Page 5] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 MN WAN AAA IPCN (MAG) (LMA) 1)|<----------Beacon--------| | | 2)|<----------Probe-------->| | | | | | | | 802.11 Auth| | | 3)|<----------------------->| | | | | | | | 802.11 Association| | | 4)|<----------------------->| | | | | | | 5)|<----EAP Req/Identity----| | | | | | | 6)|----EAP Resp/Identity----|->--EAP Resp/Identity--->| | | | | | 7)|<-EAP Req/AKA-Challenge<-|--EAP Req/AKA-Challenge--| | | | | | 8)|-EAP Resp/AKA-Challenge--|>EAP Resp/AKA-Challenge->| | | | | | 9)|<-----EAP Success------<-|------EAP Success--------| | | | | | 10)|<====== 802.11 Data ====>|<=========== 802.11Data ====Tunnel to=>| | | | core network| | | | | Figure 1: Example EAP Deployment The figure shows separate Wi-Fi Access Point and Wi-Fi Access Controller, following the split-MAC model of CAPWAP [RFC5415]. A particular deployment may have the two functions within a single node. 1. An MN detects a beacon from a WAP in the vicinity. 2. The MN probes the WAP to determine suitability to attach (Verify SSID list, authentication type and so on). 3. The MN initiates the IEEE 802.11 Authentication with the Wi-Fi network. In WPA/WPA2 mode, this is an open authentication without any security credential verification. 4. The MN initiates 802.11 Association with the Wi-Fi network. 5. The Wi-Fi network initiates 802.1X/EAP Authentication procedures by sending EAP Request/Identity. 6. The MN responds with its permanent or temporary identity. Valmikam & Koodli Expires July 9, 2015 [Page 6] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 7. The Wi-Fi network challenges the MN to prove its identity by sending EAP Request/AKA-Challenge. 8. The MN calculates the security digest and responds with EAP Response/AKA-Challenge. 9. If the authentication is successful, the Wi-Fi network responds to the MN with EAP Success. 10. An end-to-End data path is available for the MN to start IP layer communication (DHCPv4, IPv6 Router Solicitation and so on). 4. New EAP Attributes The following sections define the new EAP attributes and their usage. 4.1. APN Selection In a Wi-Fi network, an MN includes the AT_VIRTUAL_NETWORK_ID attribute in the EAP-Response/AKA-Challenge to indicate the desired APN identity for the first PDN connection. If the MN does not include the AT_VIRTUAL_NETWORK_ID attribute in the EAP-Response/AKA-Challenge, the network may select an APN by other means. This selection mechanism is outside the scope of this document. An MN includes the AT_VIRTUAL_NETWORK_REQ attribute to indicate single or multiple PDN capability. In addition, a sub-type in the attribute indicates IPv4, IPv6, or dual IPv4v6 PDN connectivity. 4.2. Connectivity Type An MN indicates its preference for connectivity using the AT_CONNECTIVITY_TYPE attribute in the EAP-Response/AKA-Challenge message. The preference indicates whether the MN wishes connectivity to the Evolved Packet Core (the so-called "EPC PDN connectivity") or Internet Offload (termed as "Non-Seamless Wireless Offload"). The network makes its decision and replies with the same attribute in the EAP Success message. 4.3. Wi-Fi to UTRAN/E-UTRAN Mobility When a multi-access MN enters a Wi-Fi network, the following parameters are applicable in the EAP-Response/AKA-Challenge for IP session continuity from UTRAN/E-UTRAN. Valmikam & Koodli Expires July 9, 2015 [Page 7] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 o AT_HANDOVER_INDICATION: This attribute indicates to the network that the MN intends to continue the IP session from UTRAN/E-UTRAN. If a previous session can be located, network will honor this request by connecting the Wi-Fi access to the existing IP session. o AT_HANDOVER_SESSION_ID: An MN MAY use this attribute to identify the session on UTRAN/E-UTRAN. If used, this attribute contains P-TMSI (Packet Temporary Mobile Subscriber Identity) if the previous session was on UTRAN or M-TMSI (Mobile Temporary Mobile Subscriber Identity) if the previous session was on E-UTRAN. This attribute helps the network correlate the Wi-Fi session to an existing UTRAN/E-UTRAN session. 4.4. MN Serial ID The MN_SERIAL_ID attribute defines an MN's serial number, including International Mobile Equipment Identity (IMEI) and International Mobile Equipment Identity Software Version (IMEISV). The IMEI (or IMEISV) is used for ensuring a legitimate (and not a stolen) device is in use. As with the others, this attribute is exchanged with the service provider's AAA server. The MN_SERIAL_ID MUST NOT be propagated further by the AAA server to any other node. 5. Attribute Extensions The format for the new attributes follows that in [RFC4187]. Note that the Length field value is inclusive of the first two bytes. 5.1. AT_VIRTUAL_NETWORK_ID The AT_VIRTUAL_NETWORK_ID attribute identifies the virtual IP network that the MN intends to attach to. The implementation of the virtual network on the core network side is technology specific. For instance, in a 3GPP network, the virtual network is implemented based on the 3GPP APN primitive. This attribute SHOULD be included in the EAP-Response/AKA-Challenge message. Valmikam & Koodli Expires July 9, 2015 [Page 8] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_VIRTUAL | Length | Virtual Network Id | | _NETWORK_ID | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Virtual Network Id | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: AT_VIRTUAL_NETWORK_ID EAP Attribute Virtual Network Id: An arbitrary octet string that identifies a virtual network in the access technology the MN is attaching to. For instance, in 3GPP E-UTRAN, this could be an APN. See [TS-23.003] for encoding of the field. 5.2. AT_VIRTUAL_NETWORK_REQ When an MN intends to connect an APN, it SHOULD use this attribute to indicate different capabilities to the network. In turn, the network provides what is supported. From the MN, this attribute can be included only in EAP-Response/ Identity. From the network, it SHOULD be included in the EAP Request/AKA-Challenge message. In the MN-to-network direction, the Type field (below) indicates the MN's request. In the network-to-MN direction, the Type field indicates network's willingness to support the request; a present Type field value indicates the network support for that Type. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_VIRTUAL_ | Length | Virt-Net-Req | Virt-Net-Req | |NETWORK_REQ | | Type | Sub-type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: AT_VIRTUAL_NETWORK_REQ EAP Attribute Virt-Net-Req Type: Type can have one of the following values: o TBA IANA: Reserved Valmikam & Koodli Expires July 9, 2015 [Page 9] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 o TBA IANA: Single PDN connection o TBA IANA : Multiple PDN connection. Can request Non-Seamless Wi- Fi Offload or EPC connectivity (see the Connectivity Type attribute below) Virt-Net-Req Sub-type: Sub-type can have one of the following values: o TBA IANA : Reserved o TBA IANA : PDN Type: IPv4 o TBA IANA : PDN Type: IPv6 o TBA IANA : PDN Type: IPv4v6 5.3. AT_CONNECTIVITY_TYPE An MN uses this attribute to indicate whether it wishes the connectivity type to be Non-Seamless WLAN Offload or EPC. This attribute is applicable for multiple PDN connections only. From the MN, this attribute can be included only in EAP-Response/ Identity. From the network, it SHOULD be included in the EAP Request/AKA-Challenge message. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_CONNECTIVITY| Length | Connectivity | Reserved | |_TYPE | | Type | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: AT_CONNECTIVITY_TYPE EAP Attribute Connectivity Type: Connectivity Type can have one of the following values: o TBA IANA : Reserved o TBA IANA : Non-Seamless WLAN Offload (NSWO) o TBA IANA : EPC PDN connectivity Valmikam & Koodli Expires July 9, 2015 [Page 10] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 5.4. AT_HANDOVER_INDICATION This attribute indicates an MN's handover intention of an existing IP attachment. This attribute SHOULD be included in the EAP-Response/AKA-Challenge message. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_HANDOVER_IND| Length | Handover | Pad | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: AT_HANDOVER_INDICATION EAP Attribute Handover Type: o 0 - the MN has no intention of handing over an existing IP session, i.e., the MN is requesting an independent IP session with the Wi-Fi network without disrupting the IP session with the UTRAN/E-UTRAN. In this case, no Session Id (Section 5.5) is included. o 1 - the MN intends to handover an existing IP session. In this case, MN MAY include a Session Id (Section 5.5) to correlate this Wi-Fi session with a UTRAN/E-UTRAN session. 5.5. AT_HANDOVER_SESSION_ID When an MN intends to handover an earlier IP session to the current access network, it may propagate a session identity that can help identify the previous session from UTRAN/E-UTRAN that the MN intends to handover. This attribute is defined as a generic octet string. The MN MAY include an E-UTRAN GUTI if the previous session was an E-UTRAN session. If the previous session was a UTRAN session, the MN MAY include UTRAN Global RNC ID (MCC, MNC, RNC Id) and P-TMSI concatenated as an octet string. This attribute SHOULD be included in the EAP-Response/AKA-Challenge message. Valmikam & Koodli Expires July 9, 2015 [Page 11] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_HANDOVER_ | Length | Access | Reserved | | SESSION_ID | | Technology | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session Id | | ... | | ... | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6: AT_HANDOVER_SESSION_ID EAP Attribute Access Technology: This field represents the RAN technology from which the MN is undergoing a handover. o TBA IANA: Reserved o TBA IANA: UTRAN o TBA IANA: E-UTRAN Session Id: An octet string of variable length that identifies the session in the source access technology. As defined at the beginning of this section, the actual value is RAN technology dependent. For E-UTRAN, the value is GUTI. For UTRAN, the value is Global RNC Id (6 bytes) followed by P-TMSI (4 bytes). See [TS-23.003] for encoding of the field. 5.6. AT_MN_SERIAL_ID This attribute defines the MN's machine serial number. Examples are International Mobile Equipment Identity (IMEI) and International Mobile Equipment Identity Software Version (IMEISV). A network that requires the machine serial number for authorization purposes MUST send a request for the attribute in an EAP-Request/AKA- Challenge message. If the attribute is present, the MN SHOULD include the attribute in the EAP-Response/AKA-Challenge message. If the MN sends the attribute, it MUST be contained within an AT_ENCR_DATA attribute. An MN MUST NOT provide the attribute unless it receives the request from a network authenticated via EAP/AKA. Valmikam & Koodli Expires July 9, 2015 [Page 12] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |AT_MN_ | Length | Serial ID | Reserved | | SERIAL_ID | | Type | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MN Serial Id | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7: AT_MN_SERIAL_ID EAP Attribute Serial ID Type: This field identifies the type of the MN Identifier. o TBA IANA: Reserved o TBA IANA: IMEI o TBA IANA: IMEISV MN Serial Id: An arbitrary octet string that identifies the MN's machine serial number. The actual value is device-specific. See [TS-23.003] for encoding of the field. When sent by the network in the EAP-Request/ AKA-Challenge message, this field is not present, which serves as an indication for the MN to provide the attribute in the EAP-Response/ AKA-Challenge message. AT_MN_SERIAL_ID attribute MUST only be used with methods which can provide mutual (network and device) authentication, such as AKA, AKA' and EAP-SIM 6. Security Considerations This document defines new EAP attributes to extend the capability of the EAP-AKA protocol as specified in Section 8.2 of [RFC4187]. The attributes are passed between an MN and a AAA server in provider- controlled trusted Wi-Fi networks, where the Wi-Fi Access Network is a relay between the MN and the AAA server. The document does not specify any new messages or options to the EAP-AKA protocol. The attributes defined here are fields which are used in existing 3G and 4G networks, where they are exchanged (in protocols specific to 3G and 4G networks) subsequent to the mobile network authentication (e.g., using the UMTS-AKA mechanism). For the operator-controled Wi- Valmikam & Koodli Expires July 9, 2015 [Page 13] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 Fi access which is connected to the same core infrastructure as the 3G and 4G access, similar model is followed here with the EAP-AKA (or EAP-AKA', EAP-SIM) authentication. In doing so, these attribute processing, security-wise, is no worse than that in existing 3G and 4G mobile networks. The attributes inherit the security protection (integrity, replay, and confidentiality) provided by the paratmeters in the AKA(') or SIM methods ; see Section 12.6 in [RFC4187]. Furthermore, RFC 4187 requires attributes exchanged in EAP-Request/AKA-Identity or EAP- Response/AKA-Identity to be integrity-protected with AT_CHECKCODE; see Section 8.2 in [RFC4187]. This requirement applies to the AT_CONNECTIVITY_TYPE and AT_VIRTUAL_NETWORK_REQ attributes defined in this document. The AT_MN_SERIAL_ID attribute MUST have confidentiality protection provided by the AKA(') or EAP-SIM methods beyond the secure transport (such as private leased lines, VPN etc.) deployed by the provider of the trusted Wi-Fi service. Use of identifiers such as IMEI could have privacy implications, wherein devices can be profiled and tracked. With additional information, this could also lead to profiling of user's network access patterns. Implementers should consult [hotos-2011] and references therein for a broader discussion and possible mitigation methods on the subject. 7. IANA Considerations This document defines the following new skippable EAP-AKA attributes. These attributes need assignments from the "EAP-AKA and EAP-SIM Parameters" registry at https://www.iana.org/assignments/eapsimaka- numbers o AT_VIRTUAL_NETWORK_ID (Section 5.1) - TBA by IANA o AT_VIRTUAL_NETWORK_REQ (Section 5.2) - TBA by IANA o AT_CONNECTIVITY_TYPE (Section 5.3) - TBA IANA o AT_HANDOVER_INDICATION (Section 5.4) - TBA by IANA o AT_HANDOVER_SESSION_ID (Section 5.5) - TBA by IANA o AT_MN_SERIAL_ID (Section 5.6) - TBA by IANA This document requests a new IANA registry "Trusted non-3GPP Access EAP Parameters". The range for both Types and Sub types in the Valmikam & Koodli Expires July 9, 2015 [Page 14] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 registry is 0 - 127, with 0 (zero) being a reserved value. The document requests IANA to make assignments in a monotonically increasing order in increments of 1, starting from 1. New assignments in this registry are made with the Specification Required policy [RFC5226]. The IANA Designated Expert should review the requirements for new assignments based on factors including, but not limited to, the source of request (e.g., standards bodies), deployment needs (e.g., industry consortium, operator community) and experimental needs (e.g., academia, industrial labs). A document outlining the purpose of new assignments should accompany the request. Such a document could be a standards document, or a research project description. The Designated Expert should consider that there is sufficient evidence of potential usage both on the end-points (e.g., Mobile Devices etc.) and the infrastructure (e.g., AAA servers, gateways etc.) The document requests assignments from the new registry for the following fields defined in this document: o Virt-Net-Req Type (Section 5.2) - TBA by IANA o Virt-Net-Req Sub type (Section 5.2) - TBA by IANA o Connectivity Type (Section 5.3) - TBA IANA o Access Technology (Section 5.5) - TBA by IANA o Serial ID Type (Section 5.6) - TBA by IANA 8. Acknowledgment Thanks to Sebastian Speicher for the review and suggesting improvements. Thanks to Mark Grayson for proposing the MN Serial ID attribute. And, thanks to Brian Haberman for suggesting a new registry. 9. References 9.1. Normative References [RFC4187] Arkko, J. and H. Haverinen, "Extensible Authentication Protocol Method for 3rd Generation Authentication and Key Agreement (EAP-AKA)", RFC4187, January 2006, <http://tools.ietf.org/html/rfc4187>. Valmikam & Koodli Expires July 9, 2015 [Page 15] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [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. 9.2. Informative References [EPC] "General Packet Radio Service (GPRS); enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access, 3GPP TS 23.401 8.8.0, December 2009.", <http://www.3gpp.org/ftp/Specs/html-info/23401.htm>. [EPC2] "Architecture enhancements for non-3GPP accesses, 3GPP TS 23.402 8.8.0, December 2009.", <http://www.3gpp.org/ftp/Specs/html-info/23402.htm>. [GPRS] "General Packet Radio Service (GPRS); Service description, Stage 2, 3GPP TS 23.060, December 2006", <http://www.3gpp.org/ftp/Specs/html-info/23060.htm>. [IEEE802.11u] "802.11u-2011 - IEEE Standard for Information Technology- Telecommunications and information exchange between systems- Local and Metropolitan networks-specific requirements- Part II: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Amendment 9: Interworking with External Networks", , Feb 2011, <http://standards.ieee.org/findstds/ standard/802.11u-2011.html>. [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H. Levkowetz, Ed., "Extensible Authentication Protocol (EAP)", RFC3748, June 2004, <http://www.ietf.org/rfc/rfc3748.txt>. [RFC4186] Haverinen, H. and J. Salowey, "Extensible Authentication Protocol Method for Global System for Mobile Communications (GSM) Subscriber Identity Modules (EAP- SIM)", RFC 4186, January 2006. [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. Valmikam & Koodli Expires July 9, 2015 [Page 16] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 [RFC5415] Calhoun, P., Montemurro, M., and D. Stanley, "Control And Provisioning of Wireless Access Points (CAPWAP) Protocol Specification", RFC5415, January 2009, <http://www.ietf.org/rfc/rfc5415.txt>. [RFC5448] Arkko, J., Lehtovirta, V., and P. Eronen, "Improved Extensible Authentication Protocol Method for 3rd Generation Authentication and Key Agreement (EAP-AKA')", RFC 5448, May 2009. [TS-23.003] "3rd Generation Partnership Project: Numbering, Addressing and Identification, 3GPP TS 23.003 12.2.0, March 2014.", , <http://www.3gpp.org/ftp/Specs/html-info/23003.htm>. [TS-33.402] "3GPP System Architecture Evolution (SAE); Security aspects of non-3GPP accesses, 3GPP TS 33.402 8.6.0, December 2009.", , <http://www.3gpp.org/ftp/Specs/html-info/33402.htm>. [hotos-2011] D. Wetherall et al., , "Privacy Revelations for Web and Mobile Apps.", Proceedings of the Hot Topics in Operating Systems (HotOS) , May 2011, <https://www.usenix.org/legacy/events/hotos11/tech/>. [hs20] "Hotspot 2.0 (Release 2) Technical Specification Package v1.0.0", , <https://www.wi-fi.org/hotspot-20-release-2- technical-specification-package-v100>. Appendix A. Change Log o: Initial Draft o: v01: status to Informational, Updated References, Revised the Figure o: No changes from 01 to 02 o: Per recent 3GPP updates, added the Connectivity Type attribute to allow indicating Non-Seamless WLAN Offload or EPC connectivity o: version-04: Revised AT_VIRTUAL_NETWORK_REQ to include 1) single PDN vs Multiple PDN connections, 2) PDN Types, and referred to NSWO Connectivity Type attribute Valmikam & Koodli Expires July 9, 2015 [Page 17] Internet-Draft EAP Attributes for Wi-Fi - EPC Integration January 2015 o: version 05: Added AT_MN_SERIAL_ID. Revised the IANA Considerations section o: version 06, 07: various edits o: AD review revs o: version 09: IETF LC, Directorate review revs o: IANA Section revision, based on IANA interaction o: version 12 - clarified/revised: 1) IMEI purpose, 2) attributes requirement in PMIP6 signaling, 3) references to 802.11u, HotSpot 2.0 (seamless roaming) 4) References (normative/informative), 5) editorial corrections o: version 13 - revised AT_MN_SERIAL_ID processing per IESG DISCUSS o: version 14 -clarified usage of AT_MN_SERIAL_ID. Provided additional reference to "trusted" Wi-Fi access. o: version 15,16: Addressed IESG comments. Revised Figure. Authors' Addresses Ravi Valmikam Unaffiliated USA Email: valmikam@gmail.com Rajeev Koodli Intel USA Email: rajeev.koodli@intel.com Valmikam & Koodli Expires July 9, 2015 [Page 18]