REIN: Robust and Efficient
Internet Infrastructure
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The phenomenal growth of computer networks has far
outpaced our development of fundamental principles to
understand them and practical techniques to effectively
manage our computer network infrastructure. There are two
substantial and engaging technical challenges:
- Multiple autonomous
entities: A particular character of many computer
networks is that their infrastructure is controlled by
multiple autonomous entities. For example, the global
Internet consists of a large number of interconnected
autonomous systems (ASes), each of which owns part of the
global Internet and conducts its own network management;
the emerging peer-to-peer paradigm empowers end hosts to
improve their collective application performance, but
often is at odds with network provider traffic
management.
- Uncertainty: The second
challenge is that there is always substantial uncertainty
when making network management decisions. A decision
maker is limited not only by possessing only partial
information due to decentralized control but also by the
impossibility of predicting the future in terms of
traffic demand and/or network topology status.
How to understand and design robust networks where these
self-interested entities optimize their individual
objectives under uncertainty is among the most
fundamental challenges in computer networks. A key
objective of our group is to make contributions to both
the fundamental scientific advancement and the practical
deployment in this fascinating, challenging and important
field. Our research so far has focused on the following
perspectives.
Robust Intradomain Traffic Engineering
How to achieve robust routing under traffic and topology
uncertainties. In [SIGCOMM06], we develop the framework
of Common-case Optimization with Penalty Envelope (COPE)
framework to improve robustness and stability with little
loss of efficiency. In [SODA07], we develop techniques to
be robust against peering links. In a recent paper, we
develop techniques to be robust against multiple
failures.
Stable and Efficient Interdomain Traffic
Engineering
Internet traffic engineering deals with how traffic
should be distributed among the autonomous networks
(called domains) in the Internet. A key challenge here is
that the traffic distribution decisions are
decentralized. To emphasize this multi-domain
perspective, Internet traffic engineering involving
multiple domains is referred to as interdomain traffic
engineering. Although the importance of interdomain
traffic engineering is widely realized, it is also
recognized that the state of art for interdomain traffic
engineering is extremely ad hoc and primitive. The
lacking in both fundamental understanding and capability
has led to low robustness, instability, and low
efficiency. As an example, during one recent event on
January 9, 2006, the Sprint backbone network was
partitioned with just two link failures, even though
there was enough redundancy in the Internet to avoid the
partition. The partition led to the disconnection of
long-distance service for millions of Sprint PCS and
Nextel wireless customers west of the Rockies, and
network partitions of many corporate networks relying on
the carrier.
Our research on interdomain traffic engineering started
with the observation that we lack fundamental
understanding on this crucially important subject. Our
first progress is the recognition that interdomain
traffic engineering is essentially a social choice
problem (i.e., aggregating individual domain preferences
to form a collective preference; see our IBC paper). This
novel perspective immediately reveals fundamental
tradeoffs that must be made on designing any interdomain
traffic engineering systems. Although some results are
impossibility results, this research, puts a science
boundary on the largely ad hoc engineering
design. Integrating the descriptive model with the notion
of rational route selection (see [ICNP 2006]) to model
operational protocols, this research not only
demonstrates the potential instability of the prevailing
interdomain traffic engineering practices but also
establishes provably-stable interdomain traffic
engineering guidelines. Guided by the fundamental
understanding, this research develops methodology for
achieving robust, efficient traffic engineering. For
example, the Reliability as an Interdomain Service (REIN)
framework [SIGCOMM07] overcomes the fundamental
limitation of individual traffic engineering, by
prompting interdomain collaboration to address challenges
such as the aforementioned Sprint event.
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Integration of Applications into
Network Traffic Management
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The multi-domain structure addressed in the REIN project
is fundamental but does not account for all of the
challenges facing Internet traffic engineering. The
additional player here is the applications, who
ultimately generate Internet traffic. While traditional
applications (e.g., Web) yield all routing decisions to
the networks, new adaptive applications such as the
overlay and peer-to-peer (P2P) applications (e.g.,
BitTorrent) conduct network-oblivious,
application-oriented routing. In less than five years,
the amount of peer-to-peer traffic in the Internet has
increased from zero to 50-80% of current total Internet
traffic. These adaptive applications, as our research
first discovered [SIGCOMM04], can interact poorly with
Internet traffic engineering and lead to significant
instability and inefficiency for both the applications
and the networks. In a most fundamental level, this
discovery reveals that there is a fundamental issue in
the traditional Internet traffic engineering
architecture: emerging applications can have tremendous
flexibility in how data is communicated; thus, they
should be an integral part of Internet traffic
engineering. However, if end hosts are to participate in
network resource optimizations, then the networks cannot
continue to be opaque but need to export their status and
policy information. Motivated by this observation, we
design a new network architecture to integrate such
applications.
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High Capacity and
Incentive-compatible Wireless Access
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For related papers, please see here.
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End Host Fairness and Rate Control
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For related papers, please see here.
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Network Localization
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For related papers, please see here.
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Security and Privacy
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For related papers, please see here.
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