COMP6050
Week 2 Exercise
Internet Multimedia Technologies By Maria Tan Since the advent of the graphical user interface, multimedia has become a popular way to present and exchange information by combining various types of content such as audio, video, text and images onto a specific medium for distribution across the internet.
With the success of multi-user environments providing common platforms for global information access, sharing, and interaction on the internet, the popularity of multimedia technologies in its many forms still continues among internet users today.
The advancement of multimedia technology in the 1990s paved the way for further developments in areas such as audio and video streaming, e-commerce, online gaming, video conferencing, and Voice over Internet Protocol (VOIP) among many other technologies which have become commonly utilized over the internet through web browsers, gaming platforms, conferencing applications, media players and other such portals.
According to the Australian Bureau of Statistics, the rate of household internet access has quadrupled over the past eight years, from 16% in 1998 to 64% in 2006–071, while the number of subscribers to retail VOIP services rose to 83% worldwide in 2005 alone2.
The success of VOIP in particular is seeing many users transfer from circuit switching telephony to digital audio communication. VOIP operates in the same manner as other audio streaming technologies where sound is encoded and transmitted as packets of data in half or full duplex connections over fibre optic cables integrated into current telephone network infrastructure.
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Week 2 Exercise
All of this popularity however, does generate disadvantages. With the increased demand of multimedia content requiring a barrage of data packets to be transmitted, an increase in traffic congestion can result while data traverses the information superhighway. This heightened information flow can in turn degrade the overall performance of successful data delivery on the internet by causing packet loss, disproportionate bandwidth distribution and delays in response time.
The underlying causes of these issues lies within the way audio and video content is streamed over the internet, and the increasing number of internet users accessing multimedia technology such as video on demand and VOIP.
Network protocols governing the way data is transmitted for web traffic such as text based and file sharing applications function differently to multimedia protocols 3
. Developed and governed by the Internet Engineering Task Force (IETF), the
traditional TCP format of transferring data differs in packet structure and resultant behaviour from the transport layer User Datagram Protocol (UDP) commonly used in streaming audio and video.
The fundamental difference between these two protocols is that UDP is primarily concerned with providing high speed data transmission over the internet, while TCP is optimized for accurate delivery rather than timely delivery4. This is due to their packet structures differing in design. UDP provides a procedure for application programs to send messages to other programs with a minimum of protocol mechanism5 by being stripped down to only 4 fields while TCP fields are divided into 11 segments which provide other functions to guarantee successful data transmission. UDP supplies minimized transmission delay by omitting the connection setup process, flow control, and retransmission6. By Maria Tan
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Because UDP operates on a bare minimum of protocol mechanism, it lacks TCP’s ability to control data flow which in turn causes the problematic “saturation point”7 issues previously mentioned. When TCP experiences network congestion it automatically slows its transmission rate through four “congestion control algorithms”8 not present in UDP. Both protocols inadvertently affect each other during peak usage times with TCP regulating packets with slower data transmission rates in the face of congestion where UDP begins to use a higher bandwidth allocation while experiencing packet loss during TCP synchronization.
To overcome these congestion issues, current internet technologies must be upgraded to accommodate the increased flood of data from fast Ethernet to Gigabit Ethernet services. As the number of internet users accessing multimedia content continues to increase, the internet backbone which distributes this information must in turn adapt to cope with these changes to support future demands.
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REFERENCES 1
“Internet access at home.” Australian Social Trends 2008. 4102.0. 23 Jul. 2008. Australian Bureau of Statistics. 8 Feb. 2009 <http://www.ausstats.abs.gov.au/Ausstats/subscriber.nsf/0/5A60A933925F7987CA25748E0012ADCF/$Fil e/internet%20access%20at%20home%20final%20version.pdf>. 2 “Internet subscribers in Australia.” Online Statistics. January 2008. Department of Broadband, Communications and the Digital Economy. 8 Feb. 2009 <http://www.archive.dbcde.gov.au/2008/01/statistical_benchmarking/online_statistics>. 3 Piecuch, M. et al. “Selective Retransmission Protocol for Multimedia on the Internet.” 5-8 Nov. 200. Worcester Polytechnic Institute. 8 Feb. 2009 < http://web.cs.wpi.edu/~claypool/papers/srp/srp.pdf>. 4 “Transmission Control Protocol.” Wikipedia. 8 Feb. 2009 <http://en.wikipedia.org/wiki/Transmission_Control_Protocol>. 5 Postel, J. “User Datagram Protocol.” RFC 768. 28 Aug. 1980. Internet Engineering Task Force. 8 Feb. 2009. <http://tools.ietf.org/html/rfc768>. 6 Hidenari, S. et al. “Characteristics of UDP Packet Loss: Effect of TCP Traffic.” Internet Society. 8 Feb. 2009. <http://www.isoc.org/INET97/proceedings/F3/F3_1.HTM>. 7 Nagle, J. “Congestion Control in IP/TCP Internetworks.” RFC 896. 6 Jan. 1984. Internet Engineering Task Force. 8 Feb. 2009 <http://tools.ietf.org/rfc/rfc896.txt>. 8 Allman, M. “TCP Congestion Control.” RFC 2581. Apr 1999. Internet Engineering Task Force. 8 Feb. 2009. <http://www.ietf.org/rfc/rfc2581.txt>
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