Subject: [IRTF-Announce] DTNRG update

From: Aaron Falk <[email-masked]>
Date: Wed, 6 Feb 2008 13:48:37 -0800

Delay-Tolerant Networking RG Report
K. Fall
S. Farrell

The Delay-Tolerant Networking Research Group (DTNRG) is a research
group chartered as part of the Internet Research Task Force (IRTF).
Members of DTNRG are concerned with how to address the architectural
and protocol design principles arising from the need to provide
interoperable communications with and among extreme and performance- 
challenged
environments where continuous end-to-end connectivity cannot be assumed.
Said another way, we are concerned with interconnecting highly  
heterogeneous
networks together even if end-to-end connectivity may never be  
available.
Examples of such environments include spacecraft, military/tactical,
some forms of disaster response, underwater, and some forms of ad-hoc
sensor/actuator networks. It may also include Internet connectivity in
places where performance may suffer such as developing parts of the  
world.

The research group has published 2 RFCs in 2007:
	RFC4838 - Delay Tolerant Networking Architecture (Informational)
	RFC5050 - Bundle Protocol Specification (Experimental)

There are a few areas of current work that are fairly mature and
are likely to be completed as RFCs in 2008:
	LTP - a transport protocol for high-delay environments
	Security - authentication and privacy for the DTN bundle protocol
		There was agreement at a meeting held in Dublin to
		favor counter-node crypto because of its length-preserving
		properties.  This becomes important when fragmentation
		is performed.

A few noteworthy technical items have arisen:
	structure of the namespace:
		DTN uses URIs to identify endpoints, which include
		a scheme.  Ongoing discussion revolves around the
		semantics associated with these schemes and how applications
		make use of them
	bit-level reliability:
		the bundle protocol does not currently contain a checksum
		or CRC on the data (or "blocks", similar to headers).  Some
		folks involved in the RG would like to add this capability.
		[The security protocol uses a mechanism to ensure bundle
		contents are not modified intentionally on unintentionally
		in transit, but some feel it may be too heavyweight]
	multicast:
		although this issue has received some attention in the past,
		not much activity has been seen recently.  The interaction
		with multicast and custody transfer can be tricky,
		and remains an area of investigation.

Futures:
	DTNRG will meet at the next IETF in Philadelphia

	Upcoming discussions are likely to include some of the
	above technical issues, in addition to the future of one
	or more "reference implementation(s)" [RI] of the bundle protocol.
	At present, we have one identified RI, but there are now multiple
	implementations that have been demonstrated to interoperate
	during a "DTN interop" held at IETF 67.  Issues revolve
	around whether there should be more than one RI for
	different operating environments and what the real purpose(s)
	of it/they are, such as: education, demonstration, performance,
	etc..

URL:
	http://www.dtnrg.org
	http://irtf.org/dtnrg
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