[MULTIMOBSEC-API] Fwd: [Int-area] BOF: Transport-Enhancing Refinements to the Network Layer Interface (TERNLI)
Pekka Nikander <pekka.nikander@nomadiclab.com> Mon, 12 June 2006 08:20 UTC
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From: Pekka Nikander <pekka.nikander@nomadiclab.com>
Date: Mon, 12 Jun 2006 11:18:28 +0300
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Subject: [MULTIMOBSEC-API] Fwd: [Int-area] BOF: Transport-Enhancing Refinements to the Network Layer Interface (TERNLI)
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FYI. --Pekka Begin forwarded message: > From: Lars Eggert <lars.eggert@netlab.nec.de> > Date: June 12, 2006 10:33:14 GMT+03:00 > To: ietf@ietf.org, tsvwg@ietf.org, int-area@ietf.org, mobopts@irtf.org > Subject: [Int-area] BOF: Transport-Enhancing Refinements to the > Network Layer Interface (TERNLI) > Reply-To: ternli@ietf.org > > Hi, > > please note that the TSV and INT are sponsoring the following non- > WG-forming BOF in Montreal. We'd welcome any input you may have on > the scope or content of this BOF. This discussion should take place > on the BOF mailing list. > > 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 > > > BACKGROUND > > 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, such as 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. > > > SCOPE > > 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. > > > DISCUSSION MATERIAL > > 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. > > > FURTHER READING > > 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/tools/rfcmarkup/rfcmarkup.cgi?draft=draft-iab- > link-indications-04.txt > > K. Ramakrishnan, S. Floyd and D. Black. The Addition of Explicit > Congestion Notification (ECN) to IP. RFC 3168, September 2001. > http://tools.ietf.org/tools/rfcmarkup/rfcmarkup.cgi?rfc=3168 > > 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/tools/rfcmarkup/rfcmarkup.cgi? > rfc=&draft=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/tools/rfcmarkup/rfcmarkup.cgi? > rfc=&draft=draft-schuetz-tcpm-tcp-rlci-00 > > -- > Lars Eggert NEC Network > Laboratories > > > _______________________________________________ > Int-area mailing list > Int-area@lists.ietf.org > https://www1.ietf.org/mailman/listinfo/int-area _______________________________________________ MULTIMOBSEC-API mailing list MULTIMOBSEC-API@ietf.org https://www1.ietf.org/mailman/listinfo/multimobsec-api
- [MULTIMOBSEC-API] Fwd: [Int-area] BOF: Transport-… Pekka Nikander
- Re: [MULTIMOBSEC-API] Fwd: [Int-area] BOF: Transp… Miika Komu