Network Working Group B. Patil Internet-Draft Nokia Intended status: Standards Track K. Chowdhury Expires: April 30, 2009 Starent Networks October 27, 2008 DHCP options for Access Point Name and attach type indication draft-patil-dhc-apn-attachtype-options-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 30, 2009. Patil & Chowdhury Expires April 30, 2009 [Page 1] Internet-Draft APN and ATTACH_Type Options October 2008 Abstract Cellular data networks which are based on 3GPP standards use the concept of Access Point Name. A mobile node which attaches via a 3GPP access network indicates thru layer 2 signaling the access point name to which connectivity is desired. This document specifies a DHCP option which enables the mobile node to request the access point name in DHCP messages. A mobile node whose mobility is managed by the network using Proxy Mobile IPv6 protocol may perform a handover from one access technology to another. A DHCP option which enables the host to indicate if the attachment via the new interface is a handover or another connction is also specified. Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. DHCP options for APN and Attach-type . . . . . . . . . . . . . 6 5. APN Information option . . . . . . . . . . . . . . . . . . . . 7 6. Attach Type Information option . . . . . . . . . . . . . . . . 8 7. Option Usage . . . . . . . . . . . . . . . . . . . . . . . . . 9 8. Mobile Node/host behavior . . . . . . . . . . . . . . . . . . 10 9. Access Router/NAS/DHCP relay agent behavior . . . . . . . . . 11 10. Security Considerations . . . . . . . . . . . . . . . . . . . 12 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 12.1. Normative References . . . . . . . . . . . . . . . . . . 14 12.2. Informative References . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 Intellectual Property and Copyright Statements . . . . . . . . . . 16 Patil & Chowdhury Expires April 30, 2009 [Page 2] Internet-Draft APN and ATTACH_Type Options October 2008 1. Requirements notation 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]. Patil & Chowdhury Expires April 30, 2009 [Page 3] Internet-Draft APN and ATTACH_Type Options October 2008 2. Introduction Cellular data networks which are based on 3GPP standards [REF 3GPP 23.060], i.e GPRS (General Packet Radio Service) define the concept of an Access Point Name (APN). The APN is an FQDN and identifies a specific gateway in the core network. Operators choose to offer different types of services via specific gateways. For example gateway 1 identified by APN1 offers Internet connectivity while gateway 2 identified by APN2 offers multi-media messaging service (MMS). A mobile node which attaches via a 3GPP access network indicates the gateway to which it needs connectivity by transmitting the APN parameter in layer 2 signaling. The APN information enables the access network to establish a tunnel to the appropriate gateway in the core. The mobile node chooses the APN based on the application in use. The application is configured to connect to the gateway through which the operator provides the service. Proxy Mobile IPv6 [RFC5213] is a network based mobility protocol. A host which is attached to a Proxy MIP6 (PMIP6) domain through an access network of type X may initiate a handover when it attaches to another access network of type Y. In order to ensure that the Local Mobility Agent (LMA) in the PMIP6 domain assigns the host the same prefix/address, the Mobility access gateway (MAG) in the network to which the host performs the handover to (i.e type y) needs to indicate that it is a handover. In the absence of any context transfer from the previous MAG to the new MAG, the host has to provide this information to the MAG. The host can indicate that the network attachment to the access network of type Y is a handover. This document specifies DHCP options which enable the host to indicate the APN to which connectivity is desired and the attach-type to be used in the case of Proxy MIP6 inter-access type handovers. Patil & Chowdhury Expires April 30, 2009 [Page 4] Internet-Draft APN and ATTACH_Type Options October 2008 3. Terminology This document refers to [RFC5213]. The term Access Point Name is defined in 3GPP [TS 23.003] in section 9.1. It is also defined below as per the 3GPP definition. Access Point Name: In the GPRS backbone, an Access Point Name (APN) is a reference to a GGSN (Gateway GPRS Serving Node). Patil & Chowdhury Expires April 30, 2009 [Page 5] Internet-Draft APN and ATTACH_Type Options October 2008 4. DHCP options for APN and Attach-type The use of APN has been limited to 3GPP networks. In the case of 3GPP accesses such as GERAN, UMTS and HSPA, a layer 2 mechanism is specified which enables the mobile node to indicate the APN parameter to the access network, and thereby being assigned a specific GGSN in the core. Recent developments now allow non-3GPP accesses such as HRPD and WiMAX to also connect to a 3GPP core network. These access types do not have a specific mechanism by which a mobile node can indicate the APN to establish a connection with. Specifying this capability as a DHCP option enables the mobile node to indicate the APN to establish a connection with at the time of network entry. Proxy Mobile IPv6 [RFC5213] does not require any changes on the host in order to support mobility. A Proxy MIP6 domain can span multiple access networks of different technologies. An MN which is attached via an interface (I1) to a PMIP6 domain may attach via another interface (I2). If the MN wants the sessions which are currently served by interface I1 to be moved to interface I2, it needs to indicate that the new network attachment is of type handover. The MN can indicate the attach type via a DHCP option during network entry and the MAG in the PMIP6 domain can use this information in the signaling to the LMA appropriately. Patil & Chowdhury Expires April 30, 2009 [Page 6] Internet-Draft APN and ATTACH_Type Options October 2008 5. APN Information option This option enables the host to indicate the access point name to which the connection needs to be established with. The host (DHCP client) includes this option in the DHCP Request message sent to the access gateway/NAS (Network Access Server) which acts as the DHCP server or relay. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_APN | Option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access Point Name | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-code OPTION_APN To be assigned by IANA Option-len The length of the APN option in units of octets Access Point Name The APN value chosen by the host. An example of an APN value is : internet.operatorY.com Patil & Chowdhury Expires April 30, 2009 [Page 7] Internet-Draft APN and ATTACH_Type Options October 2008 6. Attach Type Information option This option enables the host to indicate if the attach to the network is to be interpreted as a handover. This is applicable in the case the host is attaching to a PMIP6 domain. The host (DHCP client) includes the Attach type option in the DHCP Request message sent to the Access Router/Mobility Access Gateway which acts as a DHCP relay or in some cases a DHCP server. The MAG uses the Attach type information option to construct the signaling message to the Local Mobility Agent as per [RFC5213] . 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_ATTACH_TYPE | Option-Len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ATTACH_TYPE | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-code OPTION_ATTACH_TYPE To be assigned by IANA Option-len The length of the ATTACH_TYPE option in octets ATTACH_TYPE The attach type specifies the following values: Handover - 0 New Service flow - 1 Patil & Chowdhury Expires April 30, 2009 [Page 8] Internet-Draft APN and ATTACH_Type Options October 2008 7. Option Usage The requesting and sending of the proposed DHCP options follow the rules specified for DHCP options in [RFC3315]. Patil & Chowdhury Expires April 30, 2009 [Page 9] Internet-Draft APN and ATTACH_Type Options October 2008 8. Mobile Node/host behavior A mobile node includes the APN option when attaching to an access network which is served by a 3GPP core. The option is not required for access technologies which have layer 2 mechanisms. The MN/host is aware of the access type through which it is connecting and hence can make the decision to include the APN option. The MN includes the APN Option in the DHCP Request message sent to the access router/NAS. The MN is aware when it attaches via another access type if it is to be treated as a handover. If the MN prefers to move the sessions from the previous interface to the new interface it needs to indicate via the Attach_Type that it is a handover. The MN includes the Attach_type option in the DHCP request message. Patil & Chowdhury Expires April 30, 2009 [Page 10] Internet-Draft APN and ATTACH_Type Options October 2008 9. Access Router/NAS/DHCP relay agent behavior An access router/gateway which also acts as a NAS and includes either a DHCP relay function or in some cases acts as a DHCP server receives the DHCP request message which includes either the APN option or the Attach_type option or both. The gateway uses the APN information from the APN option to establish a bi-directional tunnel with the appropriate gateway in the 3GPP core network. The NAS/gateway resolves the IP address of the gateway in the core from the APN via DNS. The NAS/access gateway which receives the attach_type option from the MN in the DHCP Request relays this information to the PMIP6 MAG function. The MAG uses the attach_type information to set the flags in the proxy binding update (PBU) sent to the Local Mobiliity agent (LMA). Patil & Chowdhury Expires April 30, 2009 [Page 11] Internet-Draft APN and ATTACH_Type Options October 2008 10. Security Considerations The options specified in this I-D do not introduce any security vulnerabilities which are new. Patil & Chowdhury Expires April 30, 2009 [Page 12] Internet-Draft APN and ATTACH_Type Options October 2008 11. IANA Considerations IANA is requested to assign the option codes for the APN option and the Attach_Type option. Patil & Chowdhury Expires April 30, 2009 [Page 13] Internet-Draft APN and ATTACH_Type Options October 2008 12. References 12.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 12.2. Informative References [RFC5213] Gundavelli, S., "Proxy Mobile IPv6", RFC 5213, August 2008. Patil & Chowdhury Expires April 30, 2009 [Page 14] Internet-Draft APN and ATTACH_Type Options October 2008 Authors' Addresses Basavaraj Patil Nokia 6021 Connection Drive Irving, TX 75039 USA Email: basavaraj.patil@nokia.com Kuntal Chowdhury Starent Networks 20 International Place Tewksbury, MA 01876 USA Email: kchowdhury@starentnetworks.com Patil & Chowdhury Expires April 30, 2009 [Page 15] Internet-Draft APN and ATTACH_Type Options October 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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