ColloquiaTalk by Sergey Gorinsky, March 14, 2:30 pm

[Margery Ishmael]

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DEPARTMENT OF COMPUTER SCIENCE - TALK

Friday, March 14, 2003 at 2:30 pm in Ryerson 251

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Sergey Gorinsky
University of Texas at Austin
http://www.cs.utexas.edu/users/gorinsky/

Title: "Robust Congestion Control for Multicast Communications"

Abstract:

Trust is a cornerstone of most congestion control protocols
deployed in the Internet today. Unfortunately, with the growth
and commercialization of the Internet, the assumption of universal
trust is no longer tenable. A communicating entity can misbehave
to elicit a self-beneficial bandwidth allocation. Thus, design
of congestion control protocols that are robust to such misbehavior
has become an important research area.

This talk discusses design of robust congestion control for
a multicast service in the presence of distrusted receivers. We
show that protection against receiver misbehavior is harder than
in unicast and poses new research challenges. After presenting
our threat model, we classify vulnerabilities of existing
multicast congestion control protocols to receiver attacks.

Then, we focus on a specific attack of inflated subscription
which enables a misbehaving multicast receiver to acquire data at
an unfairly high rate at the expense of competing traffic. We argue
that robustness to inflated subscription requires a mechanism
for restricted group access where eligibility to access a multicast
group is a function of the congestion status. Our design guards
access to multicast groups with dynamic keys and consists of two
independent components: DELTA (Distribution of Eligibility To
Access) - a novel method for in-band distribution of the keys
to receivers that are eligible to access the groups according to
the congestion control protocol, and SIGMA (Secure Internet Group
Management Architecture) - a generic architecture for key-based
group access at edge routers. We conclude by arguing that
intrinsically different design requirements imposed by distrusted
environments point to the need for an integrative alternative to
the traditional layered approach to networking.

Host: Robert Findler

*The talk will be followed by refreshments in Ryerson 255*




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Margery Ishmael
Secretary to the Chairman, Department of Computer Science
The University of Chicago
1100 E. 58th Street, Chicago, IL. 60637-1581
tel. 773.834.8977 fax. 773.702.8487
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