dhc G. Liu Internet-Draft Y. Tu Intended status: Standards Track C. Zhu Expires: September 13, 2012 ZTE Corporation W. Hendericks D. Derksen L. Thiebaut Alcatel-Lucent March 12, 2012 DHCP Options for 3GPP Service draft-liu-dhc-3gpp-option-01.txt Abstract This document defines a new option that can be used by DHCP clients in their signaling sent to DHCP servers, when those clients need to associate a request for an IP address or IPv6 prefix with a given 3GPP packet service.It is intended for scenarios of interworking between a non-3GPP access and a 3GPP 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 September 13, 2012. Copyright 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 Liu, et al. Expires September 13, 2012 [Page 1] Internet-Draft DHCP Opt for 3GPP Service March 2012 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. Convention & Terminology . . . . . . . . . . . . . . . . . . . 4 3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 5 4. 3GPP-Service Option Format . . . . . . . . . . . . . . . . . . 6 4.1. APN Sub-option Format . . . . . . . . . . . . . . . . . . 6 4.2. Non Seamless WLAN Offload (3GPP-Service-Type)Sub-option Format . . . . . . . . . . . 7 5. DHCP Client Behavior . . . . . . . . . . . . . . . . . . . . . 8 6. DHCP Server Behavior . . . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 9. Normative References . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Liu, et al. Expires September 13, 2012 [Page 2] Internet-Draft DHCP Opt for 3GPP Service March 2012 1. Introduction The Dynamic Host Configuration Protocol (DHCP) defined in [RFC2131] provides configuration parameters to hosts on a TCP/IP based network. DHCP is built on a client-server model, where designated DHCP server allocate network addresses and deliver configuration parameters to dynamically configured hosts. The changes to [RFC2131] defined in this document defines the use of 3GPP specific option transferred to DHCP server by DHCP client. Liu, et al. Expires September 13, 2012 [Page 3] Internet-Draft DHCP Opt for 3GPP Service March 2012 2. Convention & 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 [RFC 2119]. The terminology in this document is based on the definitions in [RFC2131][RFC3315], in addition to the ones specified in this section 3GPP 3rd Generation Partnership Project TS Technical Specification EPC Evolved Packet Core APN Access Point Name PDN Packet Data Network GTP GPRS Tunnelling Protocol PMIP Proxy Mobile IP Liu, et al. Expires September 13, 2012 [Page 4] Internet-Draft DHCP Opt for 3GPP Service March 2012 3. Problem Statement In 3GPP TS 23.402, 3GPP UE can access the 3GPP EPC through non-3GPP IP access. When the non 3GPP access is Trusted, there is no need for the 3GPP UE to establish a Layer 3 tunnel (IPSec [RFC4301], DSMIPv6 [RFC 5555]) to access the EPC as it can rely upon the non 3GPP access security mechanisms. In this case, the 3GPP UE may send DHCP signaling to non 3GPP access to acquire an IP address. However, the 3GPP UE may wish to associate its request for an IP address with IP services provided by the 3GPP EPC or may conversely explicitly require that its traffic is not sent to the EPC but offloaded, even though the UE has been authenticated via its 3GPP credentials (the service is called "NSO" i.e. Non Seamless Offload). The APN (Access Point Name) is the parameter by which a 3GPP UE signals the kind of EPC service it desires. Based on the value of this parameter, a 3GPP IP Edge (a PDN GW) is selected and the PDN GW is able to determine the IP features to deliver to the traffic exchanged by the UE as part of this APN. It should be noted that the set of IP configuration parameters that the UE may receive via a DHCP response (e.g. the DNS server(s) address) may also be influenced by the value of the APN. Thus when requesting an IP address via DHCP, a 3GPP UE should be able to indicate: o Whether this IP address is for NSO or whether it is for an EPC service. o If the IP address is for an EPC service, the value of the APN corresponding to the IP services reached when using this IP address. The UE may also request an EPC service without providing an APN value; in this case, the network uses a default APN value. Such DHCP request may be sent when the UE requests access to EPC via non 3GPP access, or when the UE performs mobility from a 3GPP access to a non 3GPP access. This document is intended to define a new DHCP option for "3GPP Service". Liu, et al. Expires September 13, 2012 [Page 5] Internet-Draft DHCP Opt for 3GPP Service March 2012 4. 3GPP-Service Option Format A DHCP client within a 3GPP based device sets the "3GPP-Service" Option in the DHCP request it sends to the network to indicate the desired 3GPP service associated with that request. A DHCP server willing to indicate it has taken into account the parameters / sub-options of a "3GPP-Service" Option included by the client in a DHCP request mirrors these parameters in the DHCP signaling it sends back to the client. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 3GPP-SERVICE | option-length | sub-options... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code 3GPP-Service (TBD) option-len The number of octets in the option, minimum 1. Sub-options The "3GPP-Service" Option may contain one or more Sub-options further defined in this document Figure 1: 3GPP Service Option Format 4.1. APN Sub-option Format The purpose of 3GPP-APN (Access Point Name) Sub-option is sent by UE to network for identifing the packet data network associated with the DHCP message. The APN is defined in 3GPP TS 23.401[TS23401]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Code | Length | Value +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Code 3GPP-APN(TBD). Length The number of octets in the option, minimum 1. Value The APN value, as defined in 3GPP TS 24.008 [TS24008] section 10.5.6.1. Figure 2: APN Sub-option Format The 3GPP-APN Sub-option SHOULD only be present once in a DHCP message. If it is present more than once, the value of the last occurrence of the option supersedes the value of the other occurrences of this sub-option. Liu, et al. Expires September 13, 2012 [Page 6] Internet-Draft DHCP Opt for 3GPP Service March 2012 4.2. Non Seamless WLAN Offload (3GPP-Service-Type)Sub-option Format The purpose of 3GPP-Service-Type (Non Seamless Offload) Sub-option is to identify whether the DHCP message is to be associated with a Non Seamless Offload service or with an EPC service. The 3GPP Non Seamless Offload service is defined in 3GPP TS 23.402 [TS23402]. 0 0 1 2 3 4 5 6 7 8 9 +-+-+-+-+-+-+-+-+-+-+ | Code |S| V | +-+-+-+-+-+-+-+-+-+-+ Code 3GPP-Service-Type (TBD). S Bit 4 of octet 1 is spare and shall be coded as zero. V The 3GPP-Service-Type value, the defination is as follows, Bits 0 1 0 1 NSO 0 0 EPC All other values are reserved. Figure 3: 3GPP-Service-Type Sub-option Format The presence of the 3GPP-Service-Type Sub-option in a DHCP message indicates whether the DHCP signalling is associated with a NSO service or an EPC service rendered to the UE. The 3GPP-Service-Type Sub-option SHOULD NOT be provided in the same DHCP message than the 3GPP-APN Sub-option, when the 3GPP-Service-Type sub-option includes NSO indication. If present, the 3GPP-APN Sub- option SHOULD be provided in the same DHCP message than the 3GPP- Service-Type Sub-option, when the 3GPP-Service-Type sub-option includes EPC indication. NSO indication and EPC indication are exclusive. If the 3GPP-Service-Type Sub-option includes NSO indication, and if 3GPP-APN Sub-option is included, the 3GPP-APN Sub-option is ignored. Liu, et al. Expires September 13, 2012 [Page 7] Internet-Draft DHCP Opt for 3GPP Service March 2012 5. DHCP Client Behavior For DHCPv4 protocol, a DHCP client may include a "3GPP-Service" option in the option payload of DHCPDISCOVER and DHCP REQUEST messages being sent toward a DHCP server in order to associate its request with IP services provided by the 3GPP EPC or to explicitly require that its traffic is not sent to the EPC but offloaded For DHCPv6 protocol, DHCP client may include a "3GPP-Service" option in the option payload of SOLICIT message being sent toward a DHCP server in order to associate its request with IP services provided by the 3GPP EPC or to explicitly require that its traffic is not sent to the EPC but offloaded. If the answer from the DHCP server does not include a "3GPP-Service" option, the DHCP client assumes that the answer is not associated with an EPC service. Liu, et al. Expires September 13, 2012 [Page 8] Internet-Draft DHCP Opt for 3GPP Service March 2012 6. DHCP Server Behavior A DHCP server that receives a "3GPP-Service" option from a DHCP client but does not support this option, MUST ignore this option and MUST NOT provide this option in the signaling it sends back towards the DHCP client. Conversely, when a DHCP server has taken this option into account it MUST provide this option in the signaling it sends back towards the DHCP client. A DHCP server supporting this option SHOULD take the content of this option into account when trying to serve the DHCP client. This may involve making sure relevant signaling (e.g. GTP,PMIP [RFC5213]) is sent to an EPC gateway determined using the parameters of the "3GPP- Service" option. Liu, et al. Expires September 13, 2012 [Page 9] Internet-Draft DHCP Opt for 3GPP Service March 2012 7. Security Considerations Security considerations in DHCPv4 are described in [RFC3118]. Security considerations in DHCPv6 are described in [RFC3315]. Liu, et al. Expires September 13, 2012 [Page 10] Internet-Draft DHCP Opt for 3GPP Service March 2012 8. IANA Considerations IANA is requested to assign one new DHCP option code defined in section 5. Liu, et al. Expires September 13, 2012 [Page 11] Internet-Draft DHCP Opt for 3GPP Service March 2012 9. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [TS23401] 3GPP, "General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network(E- UTRAN) access", 2011. [TS23402] 3GPP, "Architecture enhancements for non-3GPP accesses", 2011. [TS24008] 3GPP, "Mobile radio interface Layer 3 specification; Core network protocols", 2010. Liu, et al. Expires September 13, 2012 [Page 12] Internet-Draft DHCP Opt for 3GPP Service March 2012 Authors' Addresses Guoyan Liu ZTE Corporation No.68 Zijinghua Avenue, Yuhuatai District Nanjing China Phone: +86-25-5287-1362 Email: liu.guoyan@zte.com.cn Yangwei Tu ZTE Corporation No.68 Zijinghua Avenue, Yuhuatai District Nanjing China Phone: +86-25-5287-1362 Email: tu.yangwei@zte.com.cn Chunhui Zhu ZTE Corporation No.68 Zijinghua Avenue, Yuhuatai District Nanjing China Phone: +86-25-5287-4634 Email: zhu.chunhui@zte.com.cn Wim Hendericks Alcatel-Lucent Email: Wim.Henderickx@alcatel-lucent.com Daniel Derksen Alcatel-Lucent Email: Daniel.Derksen@alcatel-lucent.com Liu, et al. Expires September 13, 2012 [Page 13] Internet-Draft DHCP Opt for 3GPP Service March 2012 Laurent Thiebaut Alcatel-Lucent Email: laurent.thiebaut@alcatel-lucent.com Liu, et al. Expires September 13, 2012 [Page 14]