[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]
Versions: 00 01 02 03 04 05 06 07 08 09 10 RFC 6258
DTN Research Group S. Symington
Internet-Draft The MITRE Corporation
Intended status: Experimental February 17, 2009
Expires: August 21, 2009
Delay-Tolerant Networking Metadata Extension Block
draft-irtf-dtnrg-bundle-metadata-block-01
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 Metadata Extension 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 Metadata Extension Block
is designed to be used to carry metadata that forwarding nodes can
use to make routing and other decisions regarding the bundle. This
block is defined to enable the actual metadata that is inserted into
the block to have any content and format, providing the format has
been documented as a metadata ontology. Specific metadata ontologies
may be defined in additional documents.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Metadata Block Format . . . . . . . . . . . . . . . . . . . . 4
3. Metadata Block Processing . . . . . . . . . . . . . . . . . . 6
3.1. Bundle Transmission . . . . . . . . . . . . . . . . . . . 6
3.2. Bundle Forwarding . . . . . . . . . . . . . . . . . . . . 6
3.3. Bundle Reception . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Normative References . . . . . . . . . . . . . . . . . . . 10
6.2. Informative References . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 11
Symington Expires August 21, 2009 [Page 2]
Internet-Draft DTN Metadata Extension 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
Metadata Block. This block is designed to be used to carry metadata
that is associated with the bundle so that forwarding nodes can use
this metadata to make routing and other decisions regarding the
bundle.
The actual metadata to be inserted into the block may have any
content and format, providing the content and format have been
defined and documented as part of an ontology in order to enable the
metadata to be interpreted. In this document we define the general
format of and the processing required to support the Metadata Block.
Separate documents will define specific metadata ontologies that are
expected to consist of various record format types.
The capabilities described in this document are OPTIONAL for
deployment with the Bundle Protocol. Bundle Protocol implementations
claiming to support the Metadata Block MUST be capable of:
-Generating a Metadata Block and inserting it into a bundle,
-Receiving bundles containing a Metadata Block and making the
information contained in this Metadata Block's ontology-specific
metadata field available for use, e.g., in forwarding decisions,
and
-Modifying the ontology-specific metadata in a received metadata
block and forwarding the modified block with the bundle
as defined in this document.
Bundle Protocol implementations claiming to support a specific
metadata ontology must both support the metadata block as defined
above and be capable of parsing and processing the metadata itself
according to the specific ontology in which the metadata is
expressed.
Symington Expires August 21, 2009 [Page 3]
Internet-Draft DTN Metadata Extension Block February 2009
2. Metadata Block Format
The Metadata 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 (1 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 Metadata Block is 0x08.
-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. There are no constraints on the
use of the Block Processing Control Flags.
-EID references (optional) - composite field defined in the bundle
protocol that is present if and only if the metadata block
references EID elements in the primary block's dictionary.
Presence of this field is indicated by the setting of the "Block
contains an EID-reference field" bit of the block processing
control flags. If EIDs are referenced in the metadata block, then
their interpretation is defined by the particular ontology that is
being used in this metadata block, as indicated in the metadata
ontology field.
-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 fields as follows:
- Metadata Ontology field (SDNV) - indicates which ontology is
to be used to interpret both the metadata in the metadata field
and the EID references in the optional EID references field (if
present). Specific ontologies are defined in separate
documents.
- Metadata field - contains the metadata itself, formatted
according to the metadata ontology that has been specified for
this block.
The Structure of a Metadata Block is as follows:
Symington Expires August 21, 2009 [Page 4]
Internet-Draft DTN Metadata Extension Block February 2009
Metadata Block Format:
+-----+------+--------------------+------+----------+----------|
|Type |Flags |EID Reference count |Len | Ontology | Metadata |
| |(SDNV)| and list (opt) |(SDNV)| | |
+-----+------+--------------------+------+----------+----------+
Figure 1
Symington Expires August 21, 2009 [Page 5]
Internet-Draft DTN Metadata Extension Block February 2009
3. Metadata Block Processing
The following are the processing steps that a bundle node must take
relative to generation, reception, and processing of Metadata 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 Metadata Blocks (as defined in this
specification).
3.2. Bundle Forwarding
The node MAY insert one or more Metadata Blocks into the bundle
before forwarding it, as dictated by local policy. The node MAY
modify the ontology-specific metadata in a received bundle before
forwarding the modified bundle, as dictated by local policy.
3.3. Bundle Reception
If the bundle includes one or more Metadata Blocks, the metadata
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 6]
Internet-Draft DTN Metadata Extension Block February 2009
4. Security Considerations
The DTN Security Overview [refs.DTNsecOver] and the Bundle Security
Protocol [refs.DTNBPsec] 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 Metadata Block and
would include that block in the calculation of their security result.
In particular, bundles including the optional Metadata 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 omit the Metadata Block from their
calculation. The fact that one or more records in the metadata block
may be modified as the bundle transits the network will not interfere
with end-to-end security protection when using ciphersuites that use
mutable canonicalisation. Lastly, the Metadata 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.
In order to provide the metadata block with confidentiality and
authentication independent of any confidentiality/authentication that
is provided for the payload or other parts of the bundle, new
ciphersuites would need to be defined for this purpose. In
particular, in order to provide confidentiality for the Metadata
Block in isolation from the rest of the bundle, a new end-to-end
confidentiality ciphersuite for use with the Confidentiality Block
(CB) that encrypts the metadata block and places the encrypted
metadata block in the security result field of the CB would need to
be defined. In order to provide authentication for the Metadata
Block in isolation from the rest of the bundle, a similar end-to-end
authentication ciphersuite for use with the Payload Security Block
(PSB) that acts only upon the Metadata Block would need to be
defined. While the definition of these ciphersuites remains to be
specified in a separate security document, the use of such
ciphersuites has been planned for in the design of the Bundle
Security Protocol.
Given that metadata can be modified by forwarding nodes, it may be
Symington Expires August 21, 2009 [Page 7]
Internet-Draft DTN Metadata Extension Block February 2009
desirable to eventually support the ability to audit changes to the
metadata at the individual record level. No such capability has been
provided in this specification as currently written.
Symington Expires August 21, 2009 [Page 8]
Internet-Draft DTN Metadata Extension Block February 2009
5. IANA Considerations
We may want to consider having IANA establish a register of Bundle
Protocol header types, with the Metadata Extension Block header
identified as type 0x08. In association with the Metadata Extension
block, we may want IANA to establish a separate register of
ontologies.
Symington Expires August 21, 2009 [Page 9]
Internet-Draft DTN Metadata Extension Block February 2009
6. References
6.1. 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., and H. Weiss, "Bundle Security
Protocol Specification",
draft-irtf-dtnrg-bundle-security-06.txt, work-in-progress,
November 2008.
6.2. 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., and H. Weiss, "Delay-Tolerant
Network Security Overview",
draft-irtf-dtnrg-sec-overview-05.txt, work-in-progress,
November 2008.
Symington Expires August 21, 2009 [Page 10]
Internet-Draft DTN Metadata Extension 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 11]
Html markup produced by rfcmarkup 1.129b, available from
https://tools.ietf.org/tools/rfcmarkup/