CoRE Working Group Y. Ma Internet-Draft X. He Intended status: Informational Hitachi (China) Research and Expires: September 2, 2012 Development Corporation Z. Cao China Mobile Mar 2012 dhcp option for CoAP Proxy Discovery draft-ma-core-dhcp-pd-01 Abstract CoAP utilizes DNS to discovery the IP address of the CoAP server. However DNS is heavy for the most resource constrained end-points. In this case the assistance from CoAP proxy or research directory (RD) is needed for CoAP transaction. This specification proposes to define one new dhcp option for proxy/RD discovery for the most resource constrained end-points. 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 2, 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 carefully, as they describe your rights and restrictions with respect Ma, et al. Expires September 2, 2012 [Page 1] Internet-Draft dhcp COAP Proxy Discovery Mar 2012 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 1.1. Conventions used in this document . . . . . . . . . . . . . 3 2. dhcp option for proxy discovery . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 5. Normative References . . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5 Ma, et al. Expires September 2, 2012 [Page 2] Internet-Draft dhcp COAP Proxy Discovery Mar 2012 1. Introduction CoAP [I-D.ietf-core-coap] is a RESTful protocol designed for constrained devices. The ultimate goal of CoAP is to enable the "Web of Things" concept, which connects the smart sensor network with the global internet. CoAP utilizes DNS for CoAP server IP address discovery. However in some circumstances, DNS is heavy to be implemented in the resource constrained nodes. In this case the assistance from CoAP proxy is needed for CoAP transaction. Also in many M2M scenarios, direct discovery of resources is not practical due to sleeping nodes, disperse networks, or networks where multicast traffic is inefficient. These problems can be solved by employing an entity called a Resource Directory (RD)[I-D.shelby-core-resource-directory], which hosts descriptions of resources held on other servers, allowing lookups to be performed for those resources . Before the CoAP sensor makes use of the CoAP proxy or RD, it must know the location of the proxy or RD. There can be multiple ways to discover the proxy's location, including both static and dynamic methods. Static configuration is a straightforward way for the client to access the server. However, in many situations, static configuration is not enough to meet the requirements. In another hand, although CoAP is assumed to be running over IPv6, there are various approaches to implement it over other protocols, SMS and GRPS for example [I-D.li-core-coap-over-sms] [I-D.becker-core-coap-sms-gprs]. There are also scenarios where IPv4 is used as the lower layer transport for CoAP. In such case the dynamic configuration method based on IPv4 protocol suite is necessary. 1.1. Conventions used in this document 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] 2. dhcp option for proxy discovery dhcp [RFC2131] provides dynamic methods to deliver configuration information to the end node. dhcp options [RFC2132] are defined to specify server information. This document specifies one new dhcp option for CoAP proxy/rd discovery. Ma, et al. Expires September 2, 2012 [Page 3] Internet-Draft dhcp COAP Proxy Discovery Mar 2012 The CoAP proxy/rd option specifies a list of CoAP proxy or Research Directory servers available to the client. Servers SHOULD be listed in order of preference. The code for the name server option is x. The minimum length for this option is 4 octets, and the length MUST always be a multiple of 4. Code Len Address 1 Address 2 +-----+-----+-----+-----+-----+-----+-----+-----+-- | x | n | a1 | a2 | a3 | a4 | a1 | a2 | ... +-----+-----+-----+-----+-----+-----+-----+-----+-- CoAP proxy/rd option 3. Security Considerations TBD. 4. IANA Considerations This document needs to register one new dhcp option number at IANA. 5. Normative References [I-D.becker-core-coap-sms-gprs] Becker, M., Li, K., Kuladinithi, K., and T. Poetsch, "Transport of CoAP over SMS, USSD and GPRS", draft-becker-core-coap-sms-gprs-01 (work in progress), March 2012. [I-D.ietf-core-coap] Frank, B., Bormann, C., Hartke, K., and Z. Shelby, "Constrained Application Protocol (CoAP)", draft-ietf-core-coap-08 (work in progress), October 2011. [I-D.li-core-coap-over-sms] Li, K., "CoAP Over SMS", draft-li-core-coap-over-sms-00 (work in progress), October 2011. [I-D.shelby-core-resource-directory] Krco, S. and Z. Shelby, "CoRE Resource Directory", Ma, et al. Expires September 2, 2012 [Page 4] Internet-Draft dhcp COAP Proxy Discovery Mar 2012 draft-shelby-core-resource-directory-02 (work in progress), October 2011. [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. [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. Authors' Addresses Yuanchen Ma Hitachi (China) Research and Development Corporation 301, Tower C North, Raycom, 2 Kexuyuan Nanlu, Haidian District Beijing 100190 China Email: ycma@hitachi.cn Xuan He Hitachi (China) Research and Development Corporation 301, Tower C North, Raycom, 2 Kexuyuan Nanlu, Haidian District Beijing 100190 China Email: xhe@hitachi.cn Zhen Cao China Mobile Unit2, 28 Xuanwumenxi Ave,Xuanwu District Beijing 100053 China Email: zehn.cao@gmail.com Ma, et al. Expires September 2, 2012 [Page 5]