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NEWTCPOverviewOur 'newtcp' program began in 2005 with support from Cisco Systems (multiple grants via their University Research Program). We were initially focused on independent, interoperable implementations of new 'high speed' TCP congestion control (CC) algorithms in FreeBSD and exploration of possible delay-based and rate-based enhancements to existing loss-based TCP CC techniques. Along the way we have also implemented and released new tools to instrument FreeBSD-based testbeds for experimental TCP research and explored how aggressive loss-based CC algorithms can dramatically increase round trip times (RTTs). In 2011 and 2012 we received new funding to (a) extend our work on delay-based TCP (particularly to mitigate the impact of bufferbloat, and work well in wireless/wired scenarios), and (b) implement multipath TCP (MPTCP) for FreeBSD and explore the impact of blending loss-based and delay-based CC on sub-flows of individual MPTCP connections. We
are revisiting path delay and flow rate as
interesting congestion indicators for TCP CC. They can potentially
allow TCP connections to utilise the network without excessive filling
of queues (cf. traditional TCP which requires queues to fill and drop
packets in order to trigger feedback). We are also exploring ways in
which delay indications can help a TCP sender differentiate between
packet losses caused by congestion or other reasons. If a delay-based
CC algorithm can exhibit loss-tolerance it may out-perform loss-based
TCP algorithms across naturally lossy paths (such as wireless links). In
2010 we released our first examples of delay-based TCP for FreeBSD. OutcomesBetween 2005 and 2011 we have :
Program MembersCollaborators
Alumni
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