[TERNLI] Re: [Iccrg] ICCRG-related BOF in Montreal: Transport-Enhancing Refinements to the Network Layer Interface (TERNLI)

Michael Welzl <michael.welzl@uibk.ac.at> Thu, 15 June 2006 12:17 UTC

Received: from [] (helo=stiedprmman1.va.neustar.com) by megatron.ietf.org with esmtp (Exim 4.43) id 1Fqqmm-0003jG-N1; Thu, 15 Jun 2006 08:17:20 -0400
Received: from [] (helo=ietf-mx.ietf.org) by megatron.ietf.org with esmtp (Exim 4.43) id 1FqXVo-00018L-Qs for ternli@ietf.org; Wed, 14 Jun 2006 11:42:32 -0400
Received: from lmr1.uibk.ac.at ([] helo=smtp.uibk.ac.at) by ietf-mx.ietf.org with esmtp (Exim 4.43) id 1FqXVn-0004xW-3J for ternli@ietf.org; Wed, 14 Jun 2006 11:42:32 -0400
Received: from lap10-c703.uibk.ac.at (lap10-c703.uibk.ac.at []) by smtp.uibk.ac.at (8.13.1/8.13.1/F1) with ESMTP id k5EFgQMA018991; Wed, 14 Jun 2006 17:42:26 +0200
From: Michael Welzl <michael.welzl@uibk.ac.at>
To: ternli@ietf.org
In-Reply-To: <0DF5D6CA-D2CC-40A5-9950-DB32BFEFECC3@netlab.nec.de>
References: <0DF5D6CA-D2CC-40A5-9950-DB32BFEFECC3@netlab.nec.de>
Content-Type: text/plain
Organization: University of Innsbruck
Message-Id: <1150299739.4774.170.camel@lap10-c703.uibk.ac.at>
Mime-Version: 1.0
X-Mailer: Ximian Evolution 1.2.2 (1.2.2-4)
Date: 14 Jun 2006 17:42:19 +0200
Content-Transfer-Encoding: 7bit
X-Scanned-By: MIMEDefang 2.52 at uibk.ac.at on
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 2bf730a014b318fd3efd65b39b48818c
X-Mailman-Approved-At: Thu, 15 Jun 2006 08:17:19 -0400
Cc: iccrg <iccrg@cs.ucl.ac.uk>
Subject: [TERNLI] Re: [Iccrg] ICCRG-related BOF in Montreal: Transport-Enhancing Refinements to the Network Layer Interface (TERNLI)
X-BeenThere: ternli@ietf.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Transport-Enhancing Refinements to the Network Layer Interface <ternli.ietf.org>
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/ternli>, <mailto:ternli-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www1.ietf.org/pipermail/ternli>
List-Post: <mailto:ternli@ietf.org>
List-Help: <mailto:ternli-request@ietf.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/ternli>, <mailto:ternli-request@ietf.org?subject=subscribe>
Errors-To: ternli-bounces@ietf.org


I also think that discussing this together with ICCRG'ers
is a good idea (and another reason for them to get moving
a bit  :-)   ).

As for a presentation, I can't make it to Montreal - Keshav,
can you?


On Wed, 2006-06-14 at 09:07, Lars Eggert wrote:
> Hi,
> please note that the TSV and INT areas are sponsoring the following  
> non-WG-forming BOF in Montreal. We'd welcome any input that ICCRG may  
> have on the scope or content of this BOF. We'd also be interested in  
> maybe seeing a short presentation from the congestion control  
> research community during the BOF.
> Thanks,
> Lars
> ----------------------------------------------------------------------
> Transport-Enhancing Refinements to the Network Layer Interface (TERNLI)
> (pronounce: "turn-ly")
> BOF Chairs:
> <tbd>
> Sponsoring Area Directors:
> Lars Eggert <lars.eggert@netlab.nec.de>
> Magnus Westerlund <magnus.westerlund@ericsson.com>
> Jari Arkko <jari.arkko@piuha.net>
> Mailing List:
> General Discussion: ternli@ietf.org
> To Subscribe: https://www.ietf.org/mailman/listinfo/ternli
> Archive: http://www.ietf.org/mail-archive/web/ternli/index.html
> The communication abstraction provided by IP at the network layer  
> delivers packets in an unordered, unreliable manner and does not  
> protect against duplication. The users of this abstraction, i.e., the  
> transport protocols, have made additional assumptions about this  
> abstraction. Many of these assumptions are critical to the effective  
> operation of important transport mechanisms, such as congestion  
> control, flow control or reliability. These assumptions include, for  
> example, that hosts remain at network locations identified by an IP  
> address on timescales that are orders of magnitude larger than the  
> duration of a communication instance. Another such assumption is that  
> packets flowing from a source to a destination mostly follow the same  
> path and that changes to that path occur on timescales that are  
> several orders of magnitude larger than the RTT between the two  
> hosts. Similarly, transport mechanisms have assumed that the  
> characteristics of such paths, such as bandwidth, delay, reordering  
> and loss probabilities, also change on timescales much larger than  
> the RTT.
> In the current Internet, many of these assumptions are no longer  
> generally true, because it has become much more dynamic in recent  
> years. Mobile hosts and whole subnetworks have started to move  
> between network locations on relatively short timescales. A growing  
> number of hosts is multi-homed, connected through multiple links with  
> possibly very different properties at the same time. The Internet has  
> incorporated new link technologies with characteristics that are much  
> more dynamic than in the past, due to functionality such as link- 
> layer retransmissions, adaptive coding or support for link-local  
> mobility.
> Several extensions to the internal functionality of the network  
> layer, such as Mobile IP, NEMO, HIP or SHIM6, support communication  
> in such dynamic environments. These extensions maintain the  
> traditional interface between network and transport layers, isolating  
> the transports from some of the dynamic effects present at and below  
> the network layer, similar to how transports remain unaware of  
> routing changes or packet fragmentation. They consequently allow  
> existing transport protocols to continue to operate without  
> modifications.
> This isolation, however, comes at a cost, because the traditional  
> communication abstraction maintained by these new network-layer  
> extensions hides information that transport-layer protocols should  
> act on. Many common transport mechanisms for congestion window  
> estimation, RTT measurements or path MTU discovery are not agile  
> enough to properly handle the significant instantaneous changes to  
> path characteristics that these network-layer extensions introduce.  
> This can, in turn, decrease the effectiveness of important transport  
> mechanisms, such as congestion control. Consequently, although  
> existing transports can operate on top of these network-layer  
> extensions to some degree, their performance and efficiency decreases.
> This BOF brings together the INT and TSV communities to discuss how  
> this inter-area problem space can be successfully approached within  
> the IETF and IRTF. Consequently, detailed presentations of specific  
> technical proposals are out-of-scope for this BOF. The BOF will also  
> *not* lead to the formation of a working group. The goal is to give  
> interested parties a venue for discussing how this problem space  
> might be sliced.
> The simple, general purpose interface between the network and  
> transport layers is one of the key features that has guaranteed the  
> evolvability of the Internet architecture, because it maintains the  
> independence of transport layers from functionality located below it,  
> and vice versa. Approaches for extending this core component must  
> therefore be broadly applicable and be of general usefulness. Point  
> solutions that optimize for specific deployment scenarios or  
> technologies are thus not relevant to this discussion.
> A possible approach might be to identify a generic, technology- 
> independent set of well-defined network- and lower-layer information  
> that has the potential to improve performance and operation of a  
> large number of different transport mechanisms and protocols and can  
> be provided in different ways by different specific underlying  
> mechanisms and technologies. This information must be optional, i.e.,  
> it might improve transport operation if present, but transports must  
> not depend on its presence.
> One existing example of an extension that follows this general  
> approach is Explicit Congestion Notification (ECN). The ECN signal is  
> well-defined and can be provided in different ways by network-layer  
> mechanisms; transport protocols act on the signal independently of  
> where and how it was generated. Another example of such an extension  
> in this spirit is Quick-Start, were routers in the network explicitly  
> signal source hosts the available capacity along the path to their  
> destinations. Transport protocols can utilize this generic,  
> technology-independent, network-layer information in different ways  
> to improve operation and performance.
> One approach forward may be to integrate these existing or proposed  
> mechanisms with additional, similar extensions that result in a  
> uniform extension to the current network-layer interface.
> The BOF organizers are interested in soliciting additional approaches  
> that attempt to address this problem space.
> L. Eggert and W. Eddy. Towards More Expressive Transport-Layer  
> Interfaces. Under Submission, June 2006.
> http://larseggert.de/papers/2006-ccr-transport-interfaces.pdf
> B. Aboba (ed.) Architectural Implications of Link Indications.  
> Internet Draft draft-iab-link-indications-04, Work in Progress,  
> December 2005.
> http://tools.ietf.org/html/draft-iab-link-indications-04
> K. Ramakrishnan, S. Floyd and D. Black. The Addition of Explicit  
> Congestion Notification (ECN) to IP. RFC 3168, September 2001.
> http://tools.ietf.org/html/rfc3168
> A. Jain, S. Floyd, M. Allman and P. Sarolahti. Quick-Start for TCP  
> and IP. Internet Draft draft-ietf-tsvwg-quickstart-03, Work in  
> Progress, April 2006.
> http://tools.ietf.org/html/draft-ietf-tsvwg-quickstart-03
> S. Schuetz, L. Eggert, W. Eddy, Y. Swami and K. Le. TCP Response to  
> Lower-Layer Connectivity-Change Indications. Internet Draft draft- 
> schuetz-tcpm-tcp-rlci-00, Work in Progress, May 2006.
> http://tools.ietf.org/html/draft-schuetz-tcpm-tcp-rlci-00
> J. Korhonen, S. Park, J. Zhang, C. Hwang and P. Sarolahti. Link  
> Characteristic Information for IP Mobility Problem Statement.  
> Internet Draft draft-korhonen-mobopts-link-characteristics-ps-01,  
> Work in Progress, June 2006.
> http://tools.ietf.org/html/draft-korhonen-mobopts-link- 
> characteristics-ps-01
Michael Welzl <michael.welzl@uibk.ac.at>
University of Innsbruck