Evaluating the influence of multiplexing schemes and buffer implementation on perceived VoIP conversation quality

Saldaña, José; Fernández-Navajas, Julián; Ruíz-Mas, José; Murillo, Jenifer; Navarro, Eduardo Viruete; Aznar, Jose I.

doi:10.1016/j.comnet.2012.02.004

Cited by 10 publications

(14 citation statements)

References 27 publications

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“…For example, in [49] an adaptive multiplexing method for VoIP was proposed, able to maintain the voice quality in acceptable limits, according to the E-Model. This subjective quality estimator was also used in [4] to evaluate the impairments caused by TCRTP optimization. The effect of traffic optimization on the subjective quality of a UDP-based FPS game was explored in [14].…”

Section: Traffic Optimization By Means Of Header Compressionmentioning

confidence: 99%

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On the effectiveness of an optimization method for the traffic of TCP-based multiplayer online games

Saldaña

2015

Multimed Tools Appl

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This paper studies the feasibility of using an optimization method, based on multiplexing and header compression, for the traffic of Massively Multiplayer Online Role Playing Games (MMORPGs) using TCP at the Transport Layer. Different scenarios where a number of flows share a common network path are identified. The adaptation of the multiplexing method is explained, and a formula of the savings is devised. The header compression ratio is obtained using real traces of a popular game and a statistical model of its traffic is used to obtain the bandwidth saving as a function of the number of players and the multiplexing period. The obtained savings can be up to 60 % for IPv4 and 70 % for IPv6. A Mean Opinion Score model from the literature is employed to calculate the limits of the multiplexing period that can be used without harming the user experience.The interactions between multiplexed and non-multiplexed flows, sharing a bottleneck with different kinds of background traffic, are studied through simulations. As a result of the tests, some limits for the multiplexing period are recommended: the unfairness between players can be low if the value of the multiplexing period is kept under 10 or 20 ms. TCP background flows using SACK (Selective Acknowledgment) and Reno yield better results, in terms of fairness, than Tahoe and New Reno. When UDP is used for background traffic, high values of the multiplexing period may stress the unfairness between flows if network congestion is severe.

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Section: Traffic Optimization By Means Of Header Compressionmentioning

confidence: 99%

“…Common network segment Native Native (4) and an additional variable delay, uniformly distributed in the interval ( -PE/2 , PE/2 ), which standard deviation, as obtained in [14], has the next value:…”

Section: Tcm Tcm Ingress Tcm Egressmentioning

confidence: 99%

On the effectiveness of an optimization method for the traffic of TCP-based multiplayer online games

Saldaña

2015

Multimed Tools Appl

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“…In [23] this effect was explored with VoIP traffic; in [24] a subjective quality estimator for a UDP-based game was used; and in [25] the effect on a TCP-based game was studied. In addition, if a flow of TCP ACKs is multiplexed, the additional delay may have an impact on TCP dynamics, taking into account that this protocol is RTT-based.…”

Section: Related Workmentioning

confidence: 99%

Small-Packet Flows in Software Defined Networks: Traffic Profile Optimization

Saldaña¹,

Hoz²,

Fernández-Navajas³

et al. 2015

JNW

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Abstract-This paper proposes a method for optimizing bandwidth usage in Software Defined Networks (SDNs) based on OpenFlow. Flows of small packets presenting a high overhead, as the ones generated by emerging services, can be identified by the SDN controller, in order to remove header fields that are common to any packet in the flow, only during their way through the SDN. At the same time, several packets can be multiplexed together in the same frame, thus reducing the overall number of frames. The method can be useful for providing QoS while the packets are traversing the SDN. Four kinds of small-packet traffic flows are considered (VoIP, UDP and TCP-based online games, and ACKs from TCP flows). Both IPv4 and IPv6 are studied, and significant bandwidth savings (up to 68 % for IPv4 and 78 % for IPv6) can be obtained for the considered kinds of traffic. The optimization method is also applied to different public Internet traffic traces, and significant reductions in terms of packets per second are achieved. Results show that bandwidth consumption is also reduced, especially in those traces where the percentage of small packets is high. Regarding the effect on QoS, the additional delay can be kept very low (below 1 millisecond) when the throughput is high, but it may become significant for lowthroughput scenarios. Thus, a trade-off between bandwidth saving and additional delay appears in those cases.

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“…In [14] this effect was explored with VoIP; in [15] a subjective quality estimator for a UDP-based game was used; and in [16] the effect on a TCP-based game was studied. In addition, if a flow of TCP ACKs is multiplexed, the additional delay may have an impact on TCP dynamics, taking into account that this protocol is RTT-based.…”

Section: Related Workmentioning

confidence: 99%

“…The proposed method should avoid the addition of delays which could impair user's experience or may reduce the sending rate of TCP flows, as studied in [16]. The influence of optimization techniques on subjective quality for real-time services has been explored [9], [14], [15] and it has been shown that user's perceived quality can be maintained. The provision of a good quality is possible because of three facts: first, the high rates of the considered traffic patterns: VoIP generates a packet every 20 ms; inter-packet time for the studied games are 40 and 105 ms respectively; and a 100 pps ACK flow can be easily found on the Internet.…”

Section: Bytes Optimized = E+ph+n • ( M+fid+ch+e[p] )+T+g (3)mentioning

confidence: 99%