GEOPRIV M. Thomson Internet-Draft J. Winterbottom Intended status: Standards Track Andrew Expires: July 18, 2009 January 14, 2009 A BEEP Binding for the HELD Protocol draft-thomson-geopriv-held-beep-04 Status of This Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and 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 July 18, 2009. Copyright Notice Copyright (c) 2009 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 to this document. Abstract A BEEP binding is described for HELD. This binding is more suitable than the basic HTTP binding in scenarios where multiple messages are Thomson & Winterbottom Expires July 18, 2009 [Page 1] Internet-Draft HELD over BEEP January 2009 sent between the same two parties. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The HELD BEEP Profile . . . . . . . . . . . . . . . . . . . . . 3 2.1. Channel Initialization . . . . . . . . . . . . . . . . . . 4 2.2. Message Exchange Pattern . . . . . . . . . . . . . . . . . 4 2.3. Error Handling . . . . . . . . . . . . . . . . . . . . . . 4 2.4. Asynchronous Message Exchange . . . . . . . . . . . . . . . 5 3. Location Dereference and the BEEP Binding . . . . . . . . . . . 5 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 4.1. LIS Discovery and Authentication . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 5.1. BEEP Profile Registration . . . . . . . . . . . . . . . . . 7 5.2. URN sun-namespace registration for 'urn:ietf:params:xml:ns:geopriv:held:beep' . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1. Normative References . . . . . . . . . . . . . . . . . . . 8 7.2. Informative References . . . . . . . . . . . . . . . . . . 9 Thomson & Winterbottom Expires July 18, 2009 [Page 2] Internet-Draft HELD over BEEP January 2009 1. Introduction The HTTP binding for HELD [I-D.ietf-geopriv-http-location-delivery] provides a basis for the protocol, which does not encumber implementations with a complex protocol stack. However, some applications require that a requester make multiple requests in parallel to a Location Information Server (LIS). Where a requester is able to retrieve location information for large numbers of Targets, a more efficient protocol is useful. In these circumstances, relying on HTTP is suboptimal. The HTTP binding is not suitable in volume scenarios because HTTP suffers from head-of-queue blocking. This prevents multiple requests from being processed in parallel. In order to achieve higher throughput, the requester must establish multiple TCP connections in parallel. This causes HTTP to be unsuitable for applications where multiple parallel requests are expected by increasing the overheads. BEEP [RFC3080] provides a framing scheme that allows for parallel requests. BEEP uses MIME [RFC2045] for its messages, which means that no significant modifications are required to carry HELD messages. This document describes a BEEP profile for HELD. 1.1. 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]. This document covers the use of HELD as a location configuration protocol and a location dereference protocol (see [I-D.ietf-geopriv-lbyr-requirements]). For simplicity, the term Location Information Server (LIS) is used to refer to the server role for both protocols. LIS in place of Location Server (LS), which is the more correct term for the location dereference protocol. 2. The HELD BEEP Profile The BEEP profile for HELD is identified using the URN: urn:ietf:params:xml:ns:geopriv:held:beep This identifier is used in the BEEP "profile" element during channel creation. The HELD channel is a simple continuous channel that does not require any state information. Requests and their respective responses are always in the request-response form ("MSG"/"RPY"). Thomson & Winterbottom Expires July 18, 2009 [Page 3] Internet-Draft HELD over BEEP January 2009 2.1. Channel Initialization The HELD profile is started with a single "profile" request. No additional parameters are required. When initiating a channel the "profile" element is empty, as shown in the example below. Similarly, the response to channel initialization is empty. 2.2. Message Exchange Pattern The BEEP binding for HELD requires only the "MSG"/"RPY" message exchange. Each "MSG" frame contains a HELD request; for example a "locationRequest". Each "RPY" frame includes a response; for example, a "locationResponse". The following exchange demonstrates how a simple HELD location request and response are encapsulated. The "C:" and "S:" prefixes on lines are used following the convention in [RFC3080]. C: MSG 1 7 . 544 125 C: Content-Type: application/held+xml C: C: C: C: END S: RPY 1 7 . 1902 695 S: Content-Type: application/held+xml S: S: S: S: S: S: END 2.3. Error Handling Consistent with the HTTP binding, the BEEP binding for HELD does not use the "ERR" message to indicate errors at the HELD protocol level. Errors in handling HELD Requests are indicated to the requester in a "RPY" message. Errors in the BEEP message that are unrelated to the HELD protocol, Thomson & Winterbottom Expires July 18, 2009 [Page 4] Internet-Draft HELD over BEEP January 2009 such as MIME formatting problems, are indicated using the BEEP "ERR" message. This "ERR" message MAY either be empty or it could include textual feedback. 2.4. Asynchronous Message Exchange A HELD request can take varying amounts of time to process. The "responseTime" attribute in HELD is used to indicate an upper bound on this time. BEEP channels are serial in nature and BEEP mandates that the serving peer process requests in order. With these constraints, in order to achieve any substantial throughput, multiple BEEP channels would be necessary. This approach does not scale well for larger numbers of requests as response times increase. It is RECOMMENDED that for HELD on BEEP that both peers use asynchronous BEEP channels [I-D.thomson-beep-async]. Asynchronous BEEP enables the use of a single channel for multiple requests without constraints on how requests are processed or on the order of responses. Asynchronous BEEP greatly increases the potential throughput of a channel, particularly for profiles like HELD that could have widely varying response times. Without asynchronous BEEP, multiple channels MAY be used to increase throughput. 3. Location Dereference and the BEEP Binding The HELD BEEP binding can be used for dereferencing of location URIs ([I-D.ietf-geopriv-lbyr-requirements], [I-D.winterbottom-geopriv-deref-protocol]). A location URI is indicated in a "Request-URI" MIME header of the BEEP "MSG" frame. The "Request-URI" header includes an absolute path and optional query components. The folloring using ABNF [RFC5234] shows the format of the "Request-URI" header: Request-URI-Header = "Request-URI" ":" ( absolute-URI / "*" ) ; absolute-URI from RFC 3986 The "Request-URI" header includes an absolute URI [RFC3986]. The absolute URI indicates location URI that is being dereferenced, or the string "*". A value of "*" indicates that the request is a location configuration protocol request (i.e. no location URI is being dereferenced). The header MAY be omitted for a location configuration protocol request, and a value of "*" is inferred. 4. Security Considerations TLS [RFC5246] MUST be used for HELD over BEEP unless confidentiality, message integrity and authentication are assured through other means Thomson & Winterbottom Expires July 18, 2009 [Page 5] Internet-Draft HELD over BEEP January 2009 (e.g. dedicated media). Section 4.1 includes guidelines on authentication requirements. 4.1. LIS Discovery and Authentication This profile is most suited to situations where a client and LIS exchange a large number of requests over a prolonged period. It is anticipated that the client and LIS are known to each other. Based on this assumption, it is reasonable for the LIS and its clients to have pre-existing configuration that is used instead of a discovery process. In addition, authentication details and methods can be pre-configured on both nodes. Therefore, no protocol mechanisms are specified for arranging discovery and authentication for this profile. Regardless of the method used to determine the address of the LIS, a client MUST authenticate the LIS. This prevents any LIS spoofing attacks that could be used to provide falsified information or to acquire information about the client (and in turn, their clients). Authentication for the case where HELD is used as a location configuration protocol is covered in [I-D.ietf-geopriv-lis-discovery]. If this profile is used for dereferencing location URIs, the authenticated LIS identity MUST be used to determine whether the LIS is authorized to serve particular location URIs. The client authenticates the LIS for each location URI. Depending on the URI scheme, the LIS identity is validated against the URI. If a LIS cannot be identified as authoritative for a particular URI, clients MUST NOT request information from that LIS for that URI. For location URIs that include a host name, such as "https:" or "pres:" URIs, the guidelines in Section 3.1 of [RFC2818] can be applied to determine if LIS identity matches the URI. It might also be necessary for the LIS to authenticate clients. Some authorization decision is likely to be necessary in order for a client to initiate a large volume of requests, which could represent significant load on a LIS. This document does not mandate any specific authentication method; however, since TLS is required, the mandatory authentication methods for TLS are assumed to be present. Alternative authentication methods can be negotiated between the LIS and its clients. Thomson & Winterbottom Expires July 18, 2009 [Page 6] Internet-Draft HELD over BEEP January 2009 5. IANA Considerations 5.1. BEEP Profile Registration This section outlines the HELD BEEP binding in the form described in [RFC3080]. Profile Identification: urn:ietf:params:xml:ns:geopriv:held:beep Messages exchanged during Channel Creation: none Messages starting one-to-one exchanges: HELD request messages from [I-D.ietf-geopriv-http-location-delivery] and extension documents. Messages in positive replies: HELD request messages from [I-D.ietf-geopriv-http-location-delivery] and extension documents. Messages in negative replies: The HELD "error" message Messages in one-to-many exchanges: none Message Syntax: c.f., HELD [I-D.ietf-geopriv-http-location-delivery] Message Semantics: c.f., HELD [I-D.ietf-geopriv-http-location-delivery] Contact Information: c.f., the "Author's Address" section of this document 5.2. URN sun-namespace registration for 'urn:ietf:params:xml:ns:geopriv:held:beep' This section registers a new XML namespace, "urn:ietf:params:xml:ns:geopriv:held:beep", as per the guidelines in [RFC3688]. URI: urn:ietf:params:xml:ns:geopriv:held:beep Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), Martin Thomson (martin.thomson@andrew.com). XML: Thomson & Winterbottom Expires July 18, 2009 [Page 7] Internet-Draft HELD over BEEP January 2009 BEGIN HELD BEEP Binding

Namespace for HELD BEEP Binding Profile

urn:ietf:params:xml:ns:geopriv:held:beep

[[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX with the RFC number for this specification.]]

See RFCXXXX.

END 6. Acknowledgements Thanks to Francis Brosnan Blazquez for sharing his BEEP expertise in reviewing this document. 7. References 7.1. Normative References [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC3080] Rose, M., "The Blocks Extensible Exchange Protocol Core", RFC 3080, March 2001. [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. Thomson & Winterbottom Expires July 18, 2009 [Page 8] Internet-Draft HELD over BEEP January 2009 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008. [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008. [I-D.ietf-geopriv-http-location-delivery] Barnes, M., Winterbottom, J., Thomson, M., and B. Stark, "HTTP Enabled Location Delivery (HELD)", draft-ietf-geopriv-http- location-delivery-11 (work in progress), December 2008. [I-D.ietf-geopriv-lis-discovery] Thomson, M. and J. Winterbottom, "Discovering the Local Location Information Server (LIS)", draft-ietf-geopriv-lis- discovery-05 (work in progress), December 2008. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 7.2. Informative References [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [I-D.thomson-beep-async] Thomson, M., "Asynchronous Channels for the Blocks Extensible Exchange Protocol (BEEP)", draft- thomson-beep-async-01 (work in progress), November 2008. Thomson & Winterbottom Expires July 18, 2009 [Page 9] Internet-Draft HELD over BEEP January 2009 [I-D.winterbottom-geopriv-deref-protocol] Winterbottom, J., Tschofenig, H., Schulzrinne, H., Thomson, M., and M. Dawson, "An HTTPS Location Dereferencing Protocol Using HELD", draft- winterbottom-geopriv- deref-protocol-02 (work in progress), July 2008. [I-D.ietf-geopriv-lbyr-requirements] Marshall, R., "Requirements for a Location-by-Reference Mechanism", draft-ietf- geopriv-lbyr-requirements- 05 (work in progress), November 2008. Authors' Addresses Martin Thomson Andrew PO Box U40 Wollongong University Campus, NSW 2500 AU Phone: +61 2 4221 2915 EMail: martin.thomson@andrew.com URI: http://www.andrew.com/ James Winterbottom Andrew PO Box U40 Wollongong University Campus, NSW 2500 AU Phone: +61 2 4221 2938 EMail: james.winterbottom@andrew.com URI: http://www.andrew.com/ Thomson & Winterbottom Expires July 18, 2009 [Page 10]