Subject: [tae] Negotiation discussion

From: Bryan Ford <[email-masked]>
Date: Mon, 27 Jul 2009 19:32:13 +0200

Hi Dan, Andrew, Preethi,

This is in response to your tsvarea presentation today and your draft- 
wing-http-new-tech-00.

As I commented after your talk, I think the whole negotiation topic  
that you brought up is incredibly important.  I think the specific  
approach you're proposing is very sensible and perhaps really the only  
realistic option in the short term, and certainly worth pursuing  
further, likely in the application area.

In the long term as alternatives explode, I think we'll need something  
more general and scalable, and that can deal with both transport-level  
and application-level negotiation.  Jana and I actually just recently  
wrote a draft paper on this topic - our version is pie-in-the-sky and  
researchy, but I hope it might be interesting as a potential longer- 
term approach to this problem.  (And your short-term approach will  
needed to get to such a long-term approach. :) )  Here is the title,  
abstract, and URL:

"An Efﬁcient Cross-Layer Negotiation Protocol"
http://bford.info/pub/net/nego.pdf

Internet evolution often depends on either inserting new protocol  
layers or upgrading existing layers to new protocols, but both of  
these evolutionary paths are obstructed by the difficulty and  
inefficiency of determining which protocols a pair of hosts mutually  
support and prefer.  We propose a novel cross-layer Negotiation  
Protocol that sets up a complete stack of connection-oriented  
protocols at once, concurrently performing handshaking for multiple  
layers and choosing among alternative protocols for each layer in as  
few round trips as possible, often just one.  The initiator proposes a  
protocol graph explicitly encoding possible configurations along with  
protocol-specific handshake data; the peers then prune, refine, and  
atomically commit to a final configuration, exchanging messages over a  
specialized transport that can operate in-line with the negotiated  
protocol stack. Although a practical Negotiation Protocol presents  
many challenges, our initial exploration suggests that these  
challenges are solvable, and we believe addressing them is a necessary  
step toward a more evolvable Internet.

We might try to talk about these negotiation ideas tomorrow at the TAE  
Bar-BOF; see my previous message on tae and tsv-area...

Thanks,
Bryan