[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04 05 06 07 08 09 10 11 12 RFC 6259

DTN Research Group                                          S. Symington
Internet-Draft                                     The MITRE Corporation
Intended status: Experimental                          February 17, 2009
Expires: August 21, 2009


         Delay-Tolerant Networking Previous Hop Insertion Block
             draft-irtf-dtnrg-bundle-previous-hop-block-05

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 August 21, 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.








Symington                Expires August 21, 2009                [Page 1]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


Abstract

   This document defines an extension block that may be used with the
   Bundle Protocol [refs.DTNBP] within the context of a Delay-Tolerant
   Network architecture [refs.DTNarch].  This Previous Hop Insertion
   Block is designed to be inserted by a forwarding node to provide
   information to its next-hop receiving node.  This block is always
   removed from the bundle by the receiving node so that it's duration
   within the bundle lasts for exactly one hop.  It provides a general
   insertion capability to enable any node that forwards a bundle to
   insert an arbitrary record (or records) of information into the
   bundle.  While this block is defined to provide an arbitrary
   insertion capability, this specification also defines two specific,
   mandatory, information record formats for the information that may be
   carried in the Previous Hop Insertion block.  Using these mandatory
   information record formats, an insertion block may be used to
   indicate the inserting/forwarding node's endpoint ID (EID), which may
   be required in some circumstances to support certain routing
   protocols (e.g., flood routing).  This document defines the format
   and processing of this Previous Hop Insertion Block.































Symington                Expires August 21, 2009                [Page 2]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Previous Hop Insertion Block Format  . . . . . . . . . . . . .  6
   3.  Previous Hop Insertion Block Processing  . . . . . . . . . . .  8
     3.1.  Bundle Transmission  . . . . . . . . . . . . . . . . . . .  8
     3.2.  Bundle Forwarding  . . . . . . . . . . . . . . . . . . . .  8
     3.3.  Bundle Reception . . . . . . . . . . . . . . . . . . . . .  8
   4.  Mandatory Information Record Formats . . . . . . . . . . . . .  9
     4.1.  EID-only . . . . . . . . . . . . . . . . . . . . . . . . .  9
     4.2.  EID-with-Timestamp . . . . . . . . . . . . . . . . . . . .  9
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 12
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13


































Symington                Expires August 21, 2009                [Page 3]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


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 RFC 2119
   [refs.RFC2119].

   The DTN bundle protocol [refs.DTNBP] defines the bundle as its
   protocol data unit.  A bundle consists of a primary bundle block,
   which is defined in the Bundle Protocol, followed by at least one
   other type of bundle block.  The Bundle Protocol defines a single
   other type of bundle block, called a Bundle Payload block.  This
   document defines an additional, optional, bundle block called a
   Previous Hop Insertion Block.  This block is designed to be used by a
   forwarding node to insert information into a bundle before forwarding
   that bundle.  The intent of this Previous Hop Insertion Block is to
   provide a general insertion mechanism such that an arbitrary record
   of information may be inserted into the bundle by a forwarding node
   for consumption by the next-hop receiving node.  The lifetime of the
   Previous Hop Insertion Block is always exactly one hop in the DTN, so
   if a bundle containing a Previous Hop Insertion Block is received,
   the receiving node is assured that the information in this block was
   inserted by the previous node; likewise, the information in this
   block is not retained with the bundle when the bundle is forwarded.

   The information record(s) to be inserted into the block may have any
   content and format, providing the content and format have been
   defined and documented in order to enable the information to be
   understood.  In this specification we define two specific information
   record formats for use in the insertion block that MUST be supported.
   Each of these formats includes a reference to the endpoint ID
   information of the inserting node in the bundle's dictionary.
   Insertion of a node's EID strings into the bundle dictionary (if not
   already there) and insertion of a reference to those strings in a
   bundle's Previous Hop Insertion Block enables the inserting/
   forwarding node to provide its EID to its next-hop receiving node.
   This previous-hop EID information may be required in some
   circumstances to support various routing protocols (e.g., flood
   routing).  Although there may be some situations in which a node that
   receives a bundle may be able to infer the EID of the node that
   forwarded the bundle to it, there are other situations in which the
   EID of the forwarding node will not be able to be inferred by the
   receiving node.  In these situations, if there is a requirement that
   the receiving node be able to determine the EID of the forwarding
   node, the forwarding node must provide this information in the
   bundle.  This specification defines a mechanism, i.e. the Previous
   Hop Insertion Block, used in conjunction with either an EID-only or
   an EID-with-timestamp information record format, whereby a node can



Symington                Expires August 21, 2009                [Page 4]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


   insert its EID (and possibly other information) into a bundle before
   forwarding it.

   Using the information record formats that are defined in this
   document, the information that is provided in the insertion blocks at
   each node may include not only the EID of the inserting/forwarding
   node, but also a time stamp.  This information may be further
   expanded or altered through the future definition of additional
   information record formats to provide an arbitrary information record
   insertion capability.  This document defines the format and
   processing of the Previous Hop Insertion Block.  It also defines two
   mandatory information record formats.

   The capabilities described in this document are OPTIONAL for
   deployment with the Bundle Protocol.  Bundle Protocol implementations
   claiming to support Previous Hop Insertion Blocks MUST be capable of:

      -Generating a Previous Hop Insertion Block and inserting it into a
      bundle,

      -Receiving bundles containing a Previous Hop Insertion Block and
      making the information contained in this Previous Hop Insertion
      Block available for use, e.g., in forwarding decisions.

      -Deleting a Previous Hop Insertion Block from a bundle

      -Adding strings to a bundle's dictionary, and references to those
      strings to the bundle's Previous Hop Insertion Block.

   as defined in this document.





















Symington                Expires August 21, 2009                [Page 5]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


2.  Previous Hop Insertion Block Format

   The Previous Hop Insertion Block uses the Canonical Bundle Block
   Format as defined in the bundle protocol [refs.DTNBP].  That is, it
   is comprised of the following elements:

      -Block-type code (one byte) - defined as in all bundle protocol
      blocks except the primary bundle block (as described in the Bundle
      Protocol).  The block type code for the Previous Hop Insertion
      Block is 0x05.

      -Block processing control flags (SDNV) - defined as in all bundle
      protocol blocks except the primary bundle block (SDNV encoding is
      described in the Bundle Protocol).  The following block processing
      control flag MUST be set:

         -Discard block if it can't be processed.

      - Block EID reference count and EID reference (optional) -
      composite field defined in [refs.DTNBP] containing a count of EID
      references (expressed as an SDNV) followed by one or more EID
      references (each of which is expressed as a pair of SDNVs).
      Whether or not this field must be present in the block is
      determined by the information record format (see Section 4) being
      used by the block.  Presence of this field is indicated by the
      setting of the "block contains an EID reference field" flag in the
      block processing control flags.

      -Block data length (SDNV) - defined as in all bundle protocol
      blocks except the primary bundle block.  SDNV encoding is
      described in the Bundle Protocol.

      -Block-type-specific data field as follows:

         -Information Record Format ID (SDNV) - Its value identifies the
         format of the information record that comes later in the block.
         Some mandatory information record formats are specified in
         Section 4.  Additional information record formats MAY be
         defined in separate specifications.

         -Information Record (optional) - Contains the data being
         inserted by the forwarding node, formatted as identified by the
         value of the Information Record Format ID field.  Whether or
         not this field must be present in the block is determined by
         the information record format (see Section 4) being used by the
         block.

   The Structure of a Previous Hop Insertion Block is as follows:



Symington                Expires August 21, 2009                [Page 6]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


   Previous Hop Insertion Block Format:
   +------+--------------+------------------------------+--------------+
   |type  |flags (SDNV)  |EID ref count and list (comp) |length (SDNV) |
   +------+--------------+------------------------------+--------------+
   | Information Record Format ID (SDNV)| Information Record (optional)|
   +-------------------------------------------------------------------+

                                 Figure 1











































Symington                Expires August 21, 2009                [Page 7]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


3.  Previous Hop Insertion Block Processing

   The following are the processing steps that a bundle node must take
   relative to generation, reception, and processing of Previous Hop
   Insertion Blocks.

3.1.  Bundle Transmission

   When an outbound bundle is created per the parameters of the bundle
   transmission request, this bundle MAY (as influenced by local policy)
   include one or more Previous Hop Insertion Blocks (as defined in this
   specification).

3.2.  Bundle Forwarding

   Before forwarding a bundle, the node SHALL delete all of the Previous
   Hop Insertion Blocks that were in the bundle when it was received.
   The node MAY delete all strings (scheme names and scheme-specific
   parts--SSPs) in the bundle's dictionary to which no endpoint ID
   references in the bundle currently refer (if any).

   The node MAY insert one or more Previous Hop Insertion Blocks into
   the bundle before forwarding it, as dictated by local policy.  The
   node MAY insert strings into the bundle's dictionary (if needed) that
   are referenced by the Previous Hop Insertion Block.

3.3.  Bundle Reception

   If the bundle includes one or more Previous Hop Insertion Blocks, the
   information records in these blocks SHALL be made available for use
   at this node (e.g., in forwarding decisions).




















Symington                Expires August 21, 2009                [Page 8]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


4.  Mandatory Information Record Formats

   This section defines the mandatory information record formats for
   this specification.  Additional formats may be defined elsewhere.

4.1.  EID-only

   The EID-only record format has information record-format ID
   0x00000001.

   When the EID-only record format is being used, the "Block contains an
   EID-reference field" block processing control flag MUST be set,
   indicating that the Block EID reference count and EID references
   field is present in the block.  The count of EID references in this
   field MUST have a value of 1, and this count MUST be followed by a
   single EID reference (expressed as a pair of SDNVs).  This EID
   reference must be that of the node that is forwarding the bundle.

   The EID-only record format does not contain an information record
   field.

4.2.  EID-with-Timestamp

   The EID-with-Timestamp record format has record-format ID 0x00000002.

   When the EID-with-Timestamp record format is being used, the "Block
   contains an EID-reference field" block processing control flag MUST
   be set, indicating that the Block EID reference count and EID
   references field is present in the block.  The count of EID
   references in this field MUST have a value of 1, and this count MUST
   be followed by a single EID reference (expressed as a pair of SDNVs).
   This EID reference must be that of the node that is forwarding the
   bundle.

   The EID-with-Timestamp record format information record field
   consists of a single "Elapsed Time" field, which is expressed as an
   SDNV.  The value in the elapsed time field indicates the time at
   which the bundle is being processed by the forwarding node, encoded
   as a number of seconds past the bundle's creation time.












Symington                Expires August 21, 2009                [Page 9]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


5.  Security Considerations

   The DTN Bundle Security Protocol [refs.DTNBPsec] and the DTN Security
   Overview [refs.DTNsecOver] define three security-related blocks to
   provide hop-by-hop authentication, end-to-end authentication, and
   end-to-end confidentiality of bundles or parts of bundles, as well as
   a set of mandatory ciphersuites that may be used to calculate
   security results carried in these security blocks.  All ciphersuites
   that use the strict canonicalisation algorithm [refs.DTNBPsec] to
   calculate and verify security results (e.g., many hop-by-hop
   authentication ciphersuites) apply to all blocks in the bundle, and
   so would apply to bundles that include an optional Previous Hop
   Insertion Block and would include that block in the calculation of
   their security result.  In particular, bundles including the optional
   Previous Hop Insertion Block would be protected in their entirety for
   the duration of a single hop, from a forwarding node to an adjacent
   receiving node (but not from source to destination), using the
   mandatory BAH-HMAC ciphersuite defined in the Bundle Security
   Protocol.  Ciphersuites that use the mutable canonicalisation
   algorithm to calculate and verify security results (e.g., the
   mandatory PSH-RSA-SHA256 ciphersuite and most end-to-end
   authentication ciphersuites) will (correctly) omit the Previous Hop
   Insertion Block from their calculation.  The fact that several
   different instantiations of this block may be present in the bundle
   as the bundle transits the network will not interfere with end-to-end
   security protection when using ciphersuites that use mutable
   canonicalisation.  Lastly, the Previous Hop Insertion Block will not
   be encrypted by the mandatory CH-RSA-AES-PAYLOAD-PSH end-to-end
   confidentiality ciphersuite, which only allows for payload and PSH
   encryption.  If encryption of this block is desired, a ciphersuite
   would need to be defined for this purpose.




















Symington                Expires August 21, 2009               [Page 10]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


6.  IANA Considerations

   If the bundle protocol becomes a standards track protocol, then we
   may want to consider having IANA establish a register of block types,
   of which the Previous Hop Insertion Block would be one.  In addition,
   we may want IANA to establish a separate register of information
   record formats specific to the Previous Hop Insertion Block.












































Symington                Expires August 21, 2009               [Page 11]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


7.  References

7.1.  Normative References

   [refs.RFC2119]
              Bradner, S. and J. Reynolds, "Key words for use in RFCs to
              Indicate Requirement Levels", RFC 2119, October 1997.

   [refs.DTNBP]
              Scott, K. and S. Burleigh, "Bundle Protocol
              Specification", RFC 5050, November 2007.

   [refs.DTNBPsec]
              Symington, S., Farrell, S., Weiss, H., and P. Lovell,
              "Bundle Security Protocol Specification",
              draft-irtf-dtnrg-bundle-security-06.txt, work-in-progress,
              November 2008.

7.2.  Informative References

   [refs.DTNarch]
              Cerf, V., Burleigh, S., Hooke, A., Torgerson, L., Durst,
              R., Scott, K., Fall, K., and H. Weiss, "Delay-Tolerant
              Network Architecture", RFC 4838, April 2007.

   [refs.DTNsecOver]
              Farrell, S., Symington, S., Weiss, H., and P. Lovell,
              "Delay-Tolerant Network Security Overview",
              draft-irtf-dtnrg-sec-overview-05.txt, work-in-progress,
              November 2008.





















Symington                Expires August 21, 2009               [Page 12]

Internet-Draft      DTN Previous Hop Insertion Block       February 2009


Author's Address

   Susan Flynn Symington
   The MITRE Corporation
   7515 Colshire Drive
   McLean, VA  22102
   US

   Phone: +1 (703) 983-7209
   Email: susan@mitre.org
   URI:   http://mitre.org/








































Symington                Expires August 21, 2009               [Page 13]


Html markup produced by rfcmarkup 1.109, available from https://tools.ietf.org/tools/rfcmarkup/