DTN Research Group P. Lovell Internet-Draft SPARTA, Inc. Expires: April 29, 2009 October 26, 2008 DTN EID References Specification draft-irtf-dtnrg-bundle-eidrefs-00 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 29, 2009. Copyright Notice Copyright (C) The IETF Trust (2008). Lovell Expires April 29, 2009 [Page 1] Internet-Draft EID references October 2008 Abstract This document describes a convention for storing references to Delay- Tolerant Networking (DTN) Bundle Protocol (BP) endpoint identifiers [EIDs] within extension blocks of bundles. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Storage Convention . . . . . . . . . . . . . . . . . . . . . . 4 2.1. EID Reference List . . . . . . . . . . . . . . . . . . . . 4 3. Dictionary Revision . . . . . . . . . . . . . . . . . . . . . 6 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1. Normative References . . . . . . . . . . . . . . . . . . . 8 5.2. Informative References . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . . . 10 Lovell Expires April 29, 2009 [Page 2] Internet-Draft EID references October 2008 1. Introduction 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 [1]. This document defines an optional method for extensions to the DTN bundle protocol [2] to store references to endpoint addresses in the bundle dictionary. EIDs and the reference format are described in [2] section 3.5. The primary block of each bundle contains a "dictionary" byte array. The text values of the endpoint identifiers in the primary block, such as source and destination, are stored in the dictionary and references to them are stored in specific places in the primary block. DTN protocol extensions may also add endpoint identifiers to the dictionary and store references within their extension blocks. The bundle protocol agent at each node may wish to remove any dictionary entries for which references no longer exist and, to do so, must be able to locate all existing EID references in a bundle. Lovell Expires April 29, 2009 [Page 3] Internet-Draft EID references October 2008 2. Storage Convention All extension blocks use the Canonical Bundle Block Format as defined in the Bundle Protocol Specification. Each is comprised of the following elements: - Block type code - Block processing control flags - Block EID reference list (optional) - Block data length - Block-type-specific data fields The type, flags, list and length fields are common to all extension blocks and are known collectively as the "preamble". +-----------+-----------+-----------+-----------+ |type | flags (SDNV) | +-----------+-----------+-----------+-----------+ | length (SDNV) | +-----------+-----------+-----------+-----------+ | block body data | +-----------+-----------+-----------+-----------+ = (continues ... ) = +-----------+-----------+-----------+-----------+ | block body data | +-----------+-----------+-----------+-----------+ General block layout (without list) Figure 1 EID references MUST be stored in the EID reference list 2.1. EID Reference List The EID reference list is a composite field and may optionally be present in any extension block. It consists of a count field followed by that number of references. The count is an SDNV as described in [2] section 3.1. Each reference is a ordered pair of SDNVs as described in [2] section 3.5, containing: - the offset, within the dictionary, of the first character of the referenced endpoint ID's scheme name Lovell Expires April 29, 2009 [Page 4] Internet-Draft EID references October 2008 - the offset, within the dictionary, of the first character of the referenced endpoint ID's SSP Presence of the field is indicated by the setting of bit 0x40 of the block processing control flags. If bit 0x40 is not set then there is no EID reference list field, and neither count nor references may appear. +-----------+-----------+-----------+-----------+ |type | flags (SDNV) | +-----------+-----------+-----------+-----------+ | EID reference count (SDNV) | +-----------+-----------+-----------+-----------+ | ref_scheme_1 (SDNV) | ref_ssp_1 (SDNV) | +-----------+-----------+-----------+-----------+ | ref_scheme_2 (SDNV) | ref_ssp_2 (SDNV) | +-----------+-----------+-----------+-----------+ | length (SDNV) | +-----------+-----------+-----------+-----------+ | block-type-specific data | +-----------+-----------+-----------+-----------+ = (continues ... ) = +-----------+-----------+-----------+-----------+ | block-type-specific data | +-----------+-----------+-----------+-----------+ A sample block layout showing two EID references Figure 2 Extension blocks may contain EID addresses as text within their block-type-specific data section. There is no restriction on where or how these are stored. A block MUST NOT contain references in its block-type-specific data section Lovell Expires April 29, 2009 [Page 5] Internet-Draft EID references October 2008 3. Dictionary Revision Bundle nodes MUST support the EID reference scheme described above in Section 2.1. Lovell Expires April 29, 2009 [Page 6] Internet-Draft EID references October 2008 4. IANA Considerations None at this time. If the bundle protocol becomes a standards track protocol, then we may want to consider having IANA establish a register of block types, and in particular for this specification a separate register of block formats. Lovell Expires April 29, 2009 [Page 7] Internet-Draft EID references October 2008 5. References 5.1. Normative References [1] Bradner, S. and J. Reynolds, "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, October 1997. [2] Scott, K., "Bundle Protocol Specification", draft-irtf-dtnrg-bundle-spec-06.txt , August 2006. [3] Symington, S., Farrell, S., Weiss, H., and P. Lovell, "Bundle Security Protocol Specification", draft-irtf-dtnrg-bundle-security-03.txt , March 2007. 5.2. Informative References [4] Cerf, V., "Delay-Tolerant Network Architecture", draft-irtf-dtnrg-arch-07.txt , October 2006, . [5] Farrell, S., Symington, S., and H. Weiss, "Delay-Tolerant Network Security Overview", draft-irtf-dtnrg-sec-overview-02.txt , October 2006. Lovell Expires April 29, 2009 [Page 8] Internet-Draft EID references October 2008 Author's Address Peter Lovell SPARTA, Inc. 7110 Samuel Morse Drive Columbia, MD 21046 US Phone: +1-443-430-8052 Email: peter.lovell@sparta.com Lovell Expires April 29, 2009 [Page 9] Internet-Draft EID references 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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