overview | - | What is TeXCP? |
papers | - | TeXCP documents |
related research | - | other traffic engineering projects |
people | - | who
are we? |
funding | - | who
sponsors TeXCP? |
Internet users frequently experience congestion and service
disruption. These problems are mostly caused by inflexibility in
Internet routing, which maps a communication to a single
potentially-suboptimal path, typically for as long as the path is
available, irrespective of its congestion. Recent studies show that
better routing options usually exist- either an alternative path with
higher bandwidth or a few paths which in aggregate, provide more
throughput and higher availability. Adaptively routing traffic over
the better paths can provide a major performance gain and crucial fallback options during DoS attacks or network outages.
There are two ways to implement adaptive multipath routing: end-based
adaptation and network-based adaptation. End-based routing adaptation
includes overlay routing, inverse multiplexing, and adaptive
multihoming. Encouraged by its ease of deployment, much recent
research has explored end-based routing adaptation.
This project focuses on the less explored topic of network-based
adaptive multipath routing, where an administrative domain uses
multiple paths to deliver traffic demands between any two points,
adaptively balancing the load across these paths. This is a traffic
engineering (TE) problem but differs from prior TE work which consists
mostly of static load balancers or offline multipath route
optimizers. In contrast, this project advocates an adaptive,
distributed, multipath routing approach that rebalances load in
realtime to protect the network from congestion caused by attack
traffic, flash crowds, BGP transients, or link failures.
This project focuses on network-based adaptive multipath routing for
the following reasons. First, measurements indicate that network-based
adaptive routing can produce a big throughput and availability
gain. Past research shows that ISP networks have very high path
diversity and that over 40% of the bottlenecks are
intra-AS. Network-based multipath routing can exploit the path
diversity inside an AS to avoid these bottlenecks. Second,
network-based adaptive routing is easier to stabilize than end-based
adaptive routing. Without some form of coordination, a congested path
causes everyone to move traffic to the secondary path (or paths)
potentially causing the first path to become underutilized and the
secondary path to be congested. As a result, everyone moves traffic
back to
the first path and the cycle repeats. In an autonomous system (AS),
all nodes are under the same administration and can be loosely
coordinated so that the aggregate traffic moved from one path to
another cannot destabilize the network. Control theory tools used
in XCP are applicable in this context. Third,
network-based and end-based multipath adaptation are
complementary. Both should be studied to understand their interaction
and tradeoffs.
Traffic Engineering Projects
Traffic Matrix Estimation
M. I. T. Computer Science and Artificial Intelligence Laboratory · 200 Technology Square · Cambridge, MA 02139 · USA