摘要 :
The HTTP/1.1 protocol is the result of four years of discussion and debate among a broad group of Web researchers and developers. It improves upon its phenomenally successful predecessor, HTTP/1.0, in numerous ways. We discuss the...
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The HTTP/1.1 protocol is the result of four years of discussion and debate among a broad group of Web researchers and developers. It improves upon its phenomenally successful predecessor, HTTP/1.0, in numerous ways. We discuss the differences between HTTP/1.0 and HTTP/1.1, as well as some of the rationale behind these changes.
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摘要 :
HTTP-MPLEX is a header compression and response encoding scheme for HTTP. It is designed to compress traditional HTTP requests to conserve bandwidth, multiplex multiple responses to a single sustained stream of data to speed respo...
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HTTP-MPLEX is a header compression and response encoding scheme for HTTP. It is designed to compress traditional HTTP requests to conserve bandwidth, multiplex multiple responses to a single sustained stream of data to speed response times and improve application layer use of Transmission Control Protocol (TCP) by reducing the number of parallel connections and sustaining response bursts. HTTP 1.1 uses FIFO request and response transmission that can be susceptible to head-of-line queue starvation. HTTP-MPLEX enables the simultaneous, compressed transmission of many requests with response multiplexing and prioritisation to relieve head-of-line blocking.
To analyse the performance of HTTP-MPLEX relative to HTTP 1.1, a client and server was written in C + + with plug-in implementations of both protocols. This paper analyses the effect of request compression and response multiplexing and aggregation in the simulated network environment ns (2.29-snapshot-20050921) and with experimentation results from symmetric (high bandwidth), asymmetric (ADSL) and dial-up connections to the Internet. This paper presents the result of simulation and experimentation by retrieval of four key web-pages. A comparative analysis of protocol behaviour, total page retrieval time, request/response performance and total object retrieval time is given.
The results presented in this paper demonstrate the superior performance of HTTP-MPLEX over HTTP 1.1 in asymmetric bandwidth networks where a simulated improvement of greater than 10% and an experimental improvement of greater than 20% were achieved. In symmetric bandwidth networks HTTP-MPLEX does not significantly reduce page retrieval time. As bandwidth asymmetric technologies such as ADSL are commonly used for Internet connections at the user end, the superior performance of the proposed protocol in asymmetric networks is a significant contribution.
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摘要 :
The HTTP/1.1 protocol is the result of four years of discussion and debate among a broad group of Web researchers and developers. It improves upon its phenomenally successful predecessor, HTTP/1.0, in numerous ways. We discuss the...
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The HTTP/1.1 protocol is the result of four years of discussion and debate among a broad group of Web researchers and developers. It improves upon its phenomenally successful predecessor, HTTP/1.0, in numerous ways. We discuss the differences between HTTP/1.0 and HTTP/ 1 .1, as well as some of the rationale behind these changes.
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摘要 :
HTTP Adaptive Streaming (HAS) plays a key role in over-the-top video streaming with the
ability to reduce the video stall duration by adapting the quality of transmitted video segments
to the network conditions. However, HAS sti...
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HTTP Adaptive Streaming (HAS) plays a key role in over-the-top video streaming with the
ability to reduce the video stall duration by adapting the quality of transmitted video segments
to the network conditions. However, HAS still suffers from two problems. First, it
incurs variations in video quality because of throughput fluctuation. Adaptive bitrate (ABR)
algorithms at the HAS client usually select a low-quality segment when the throughput
drops to avoid stall events, which impairs the Quality of Experience (QoE) of the endusers.
Second, many ABR algorithms choose the lowest-quality segments at the beginning
of a video streaming session to ramp up the playout buffer early on. Although this strategy
decreases the startup time, clients can be annoyed as they have to watch a low-quality
video initially. To address these issues, we introduced the H2BR technique (HTTP/2-Based
Retransmission) (Nguyen et al. 2020) that utilizes certain features of HTTP/2 (including
server push, multiplexing, stream priority, and stream termination) for late transmissions of
higher-quality versions of video segments already in the client buffer, in order to improve
video quality. Although H2BR was shown to enhance the QoE, limited streaming scenarios
were considered resulting in a lack of general conclusions on H2BR’s performance. Thus,
this article provides a profound evaluation to answer three open questions: (i) how H2BR’s
performance is impacted by parameters at the server side (i.e., various encoding specifications),
at the network side (i.e., packet loss rate), and at the client side (i.e., buffer size) on
the performance of H2BR; (ii) how H2BR outperforms other state-of-the-art approaches in
different configurations of the parameters above; (iii) how to effectively utilize H2BR on
top of ABR algorithms in various streaming scenarios. The experimental results show that
H2BR’s performance increases with the buffer size and decreases with increasing packet
loss rates and/or video segment duration. The number of quality levels can negatively or
positively impact on H2BR’s performance, depending on the ABR algorithm deployed. In
general, H2BR is able to enhance the video quality by up to 17% and 14% in scalable
video streaming and in non-scalable video streaming, respectively. Compared with an existing
retransmission technique (i.e., SQUAD Wang et al., ACM Trans Multimed Comput Commun Applic (TOMM) 13(3s): 45, 2017), H2BR shows better results with more than
10% in QoE and 9% in the average video quality.
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