Page 153 - ITU Kaleidoscope 2016

ICTs for a Sustainable World

Total File size = File size in bits (bits) and
Actual File Transfer Rate = Rate of file transmission in
bits per second (bps).

Transfer duration results of transferring 843
Mbytes (6744Mbits) 4K-video file by using three scenarios:
multi-path (1:2sec), using Path 1 alone (GIST-B>
MY>CHULA) and using Path 2 alone (GIST-B>CHULA)
are shown in Table 6 and Figure 3. The transfer duration
results are the average results of three times tested with the
same parameter settings. According to the tested results,
file transfer duration decreases with upper bound
associated to the available link bandwidth capacity when
the target file transfer rate of Tsunami protocol increases
for all three scenarios. That result trend can be seen when
comparing the cases of target file transfer rates (100, 200, Figure 3: File transfer duration over OF@TEIN SDN cloud
300 and 400Mbps). The required transfer duration of using playground.
Path 2 alone (GIST-B>CHULA) and multi-path (1:2sec)
are similar until the target file transfer rate is up to 300 Table 7: Results of average throughput over OF@TEIN
Mbps when the link bandwidth capacity is enough to carry Testing Scenarios Throughput (Mbps)
the whole video file traffic. As for using Path 1 alone Target Transfer Rate (Mbps) 100 200 300 400 500
(GIST-B>MY>CHULA), the required file transfer duration Multi-path(1:2sec) 94.2 188.3 262.9 341.0 394.7
is higher than the other two scenarios, although there is Single-path(GIST-B>CHULA) 94.9 188.8 274.9 334.7 354.3
enough link capacity to carry the whole traffic. The reason Single-path(GIST-B>MY 91.2 134.9 268.7 226.2 303.6
is that the longer round trip time (RTT) of 125ms is >CHULA)
required for transmitting via Path 1 (via MY route) while
RTT delay via Path 2 (via a direct link to CHULA) would
require 105ms. Moreover, the RTT delay of multi-path
(1:2sec) is periodically switching between 125ms and
105ms. Therefore, the RTT delay is an important factor to
consider in order to obtain the lower transmission delay.
In the case of target file rate 400 and 500Mbps,
when the link becomes congested, the file transfer duration
results of our proposed multipath (1:2sec) case outperform
the cases using Path 1 alone and Path 2 alone. However,
the target file transfer rate of 500Mbps is not
recommended with our multi-path function because it
requires a longer delay than those of 400Mbps rate. In that
case, UDP packet losses increase due to the overloaded
links. The reason that the file transfer duration of our
proposed multi-path (1:2sec) case cannot outperform in the
cases of target file transfer rate of 100, 200, 300Mbps is Figure 4: Throughput over OF@TEIN SDN cloud playground.
that using Tsunami file-transfer protocol limits the
maximum transfer rate. Therefore, the transfer rate cannot Tables 7 and 8 show the results of file transfer
be more than the specified target rate when using our throughput and actual file transfer rate of varying target
multi-path function. The tested results of file transfer file transfer rate for three scenarios and those results are
duration confirm that using multi-path splitting function average results from tested three times with same
achieves the lowest file transfer duration time when the parameter settings. Figures 4 and 5 depict the file transfer
links are congested and do not have enough capacity to throughput and actual file transfer rate for three scenarios
carry the whole traffic by using a single path. with various target file transfer rates. Those throughput
results confirm the remarks as discussed above. The file
Table 6: Results of average file transfer duration over OF@TEIN transfer throughput shown in Table 7 and Figure 4 are the
Testing Scenarios File Transfer Duration (s) available throughput during the file transferring period.
Target Transfer Rate(Mbps) 100 200 300 400 500 According to the file transfer throughput results in the case
Multi-path(1:2sec) 72.2 36.0 25.7 23.5 26.5 of 400 and 500Mbps target file transfer rates, the
Single-path(GIST-B>CHULA) 71.0 35.7 24.9 30.4 33.0 throughput obtained by using multi-path function is higher
Single-path(GIST-B>MY>CHULA) 74.3 50.2 25.1 44.3 35.0 than that by using single-path alone. However, those file

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