Abstract
We consider scenarios with two sites connected over
a dedicated, long-haul connection that must quickly fail-over in
response to degradations in host-to-host application performance.
We present two methods for path fail-over using OpenFlowenabled
switches: (a) a light-weight method that utilizes host
scripts to monitor the application performance and dpctl API for
switching, and (b) a generic method that uses two OpenDaylight
(ODL) controllers and REST interfaces. The restoration dynamics
of the application contain significant statistical variations due to
the controllers, north interfaces and switches; in addition, the
variety of vendor implementations further complicates the choice
between different solutions. We present the impulse-response
method to estimate the regressions of performance parameters,
which enables a rigorous and objective comparison of different
solutions. We describe testing results of the two methods, using
TCP throughput and connection rtt as main parameters, over a
testbed consisting of HP and Cisco switches connected over longhaul
connections emulated in hardware by ANUE devices. The
combination of analytical and experimental results demonstrates
that dpctl method responds seconds faster than ODL method on
average, while both methods restore TCP throughput.
