[e2e] end of interest -- BP metadata / binary vs text
rkrishnan at comcast.net
Sun May 11 08:30:07 PDT 2008
My objective was to provoke discussion on the topic of whether it makes
sense to think of DTN as a session layer, as an overlay above TCP, etc.
from the e2e perspective. If you feel this topic is unsuitable for
discussion here, I will gladly stop posting on this topic here of
> I am afraid that those who treat the RFCs as scripture from high priests
> mistake dogma for thoughtfulness.
I am definitely not treating RFCs as scripture. I am not satisfied with
the explanation that DTN/BP belongs to the "session layer" as the best
or only model. I find this limiting, since DTN issues span all the way
from applications to the physical "layer".
> The essential valid measure of DTN ideas is that they work, and will
> continue to work well, *to organize the solution* to an interesting
> class of real-world problems. It is irrelevant whether they provide
> the basis for destroying some "traditional paradigm" and creating a new
Agreed. If anyone reads my post as being about destroying old religion
and creating a new one, that is missing the point. It is about getting
out of old shackles though; why keep doing the same thing (like the way
we fit seem to try to fit DTN into the old mold) and expect a different
result? If we say DTN is in the session layer, we will engineer a
useful DTN session layer alright, but will a DTN session layer solve any
fundamentally new problems? Does that limit new architectures that
could be explored?
> What made the Internet architecture useful was its attention to
> "interoperation" and to facilitating support of "unanticipated"
> applications and implementation technologies. It framed those things
> well, making progress possible. DTN ideas frame a new set of issues
> well - communcations that occur between entities that occupy
> discontiguous regions of space-time influence. Such communications
> have always existed (books communicate across time in personal and
> public libraries, postal letters transcend spatial barriers in
> self-contained form) - DTN's merely ratify their importance by focusing
> framing on those issues.
Agreed. In a DTN, among other things, we want to maximize the value of
information exchanged within a transitory encounter, and this can not be
framed entirely as a session-layer issue. Relegating DTN to the session
layer will completely isolate it from a radio-aware CLA (or whatever
name we want to call it) among other things, which relates to a point
you made earlier.
Hope that clarifies my original post somewhat.
> Rajesh Krishnan wrote:
> > Granted this matches the viewpoint presented in RFC 5050 of BP's
> > (non-threatening ;) relationship to TCP/IP.
> > By including forwarding and dynamic routing (L3?), retransmissions
> > and L2?), and persistent storage and application metadata tagging
> > concerns within the same protocol, BP does not fit harmoniously at
> L5 of
> > the TCP/IP Internet, IMHO. This challenge to traditional layering
> > precisely what I find most fascinating about DTN.
> > With the CLA/BP split, there is still layering in DTN; just that the
> > layering is not congruent to conventional TCP/IP layering.
> > DTN/BP seems to relate to TCP/IP more or less the same way IP looks
> > other network technologies. At least that is my interpretation of
> > DTN/BP as an overlay abstraction (TCP/IP is relevant only as
> > means for early deployment. ;)
> > I am speaking only for myself here (not past or present employers or
> > funding agencies or IRTF WGs), and this thread ought to migrate to
> > dtn-interest perhaps.
> > Best Regards,
> > Rajesh
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