(→TCP Congestion Control Algorithms over a live HSDPA Network) |
(→TCP Congestion Control Algorithms over a live HSDPA Network) |
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Riga 21: | Riga 21: | ||
* Differently from the case of the [[TCP_over_Umts | UMTS scenario]], the considered TCP congestion control algorithms exhibited the following characteristics in the case of the downlink channel: | * Differently from the case of the [[TCP_over_Umts | UMTS scenario]], the considered TCP congestion control algorithms exhibited the following characteristics in the case of the downlink channel: | ||
− | # | + | # TCP variants provides similar goodputs |
− | # TCP Bic | + | # TCP Bic/Cubic exhibit inflated values for average RTT due to the aggressive nature of their probing phase. TCP NewReno and TCP Westwood+ provide lower values of RTT, TCP Westwood+ exhibiting the lowest. |
− | # TCP Bic | + | # TCP Bic/Cubic provoke two times packet retransmission values with respect to TCP Westwood+ and TCP NewReno. |
− | # TCP Bic | + | # TCP Bic/Cubic provoke roughly three times the number of timeouts wrt TCP Westwood+ and TCP NewReno, TCP Cubic exhibiting the highest number. |
* In the case of the uplink channel the algorithms exhibited similar performances, due to the fact that the moderate size of cwnd forced TCP Cubic and TCP Bic to use the linear probing in order to be TCP friendly (see [http://netsrv.csc.ncsu.edu/export/cubic_a_new_tcp_2008.pdf [1]]). | * In the case of the uplink channel the algorithms exhibited similar performances, due to the fact that the moderate size of cwnd forced TCP Cubic and TCP Bic to use the linear probing in order to be TCP friendly (see [http://netsrv.csc.ncsu.edu/export/cubic_a_new_tcp_2008.pdf [1]]). |
We report results obtained by an extensive measurement campaign over a live HSDPA network involving more than 3000 flows resulting in around 60 hours of active measurements. The considered TCP variants are the following:
The experimental evaluation has been carried out by accessing the public Internet using a commercial HSDPA card (see figure below).
The following instantaneous variable measurements have been collected by using the libnetmeas library:
The main findings of the investigation can be summarized as follows:
We report cumulative distribution function plots:
We report results obtained by an extensive measurement campaign over a live HSDPA network involving more than 3000 flows resulting in around 60 hours of active measurements. The considered TCP variants are the following:
The experimental evaluation has been carried out by accessing the public Internet using a commercial HSDPA card (see figure below).
The following instantaneous variable measurements have been collected by using the libnetmeas library:
The main findings of the investigation can be summarized as follows:
We report cumulative distribution function plots: