Analysis of TFRC in Disconnected Scenarios and Performance Improvements with Freeze-DCCP
Olivier Mehani, Roksana Boreli, Thierry Ernst
We present enhancements to the TCP-Friendly Rate Control mechanism (TFRC) which
are designed to better cope with the intermittent connectivity available to
mobile devices or in Delay Tolerant Networks. Our aim is to prevent losses
during disconnected periods and quickly adapt to new network conditions. We
propose to suspend the transmission before disconnections occur in a way
inspired by Freeze-TCP, then probe, in a new way, the network after reconnecting
to enable full use of the newly available bandwidth.
We first evaluate the potential performance gains for realistic network
parameters. We then describe the proposed additions to TFRC and their
implementation within the Datagram Congestion Control Protocol (DCCP) in ns-2.
Comparisons of simulation results for example mobility scenarios show that the
proposed enhancements enable faster recovery upon reconnection as well as
significantly improved adjustment to the newly available network conditions.