Computer Sciences and Information Technology - Essay Example

? Computer Sciences and Information Technology Increase in the use of the Internet has necessitated the development of more robust systems to handle the growing demands for more reliable computer network connections. TCP is a basic transmission protocol, and forms a standard against which new non-TCP connections are gauged for network resource use efficiency. Various suppliers of multimedia products have preferences over the types of protocols they transmit they streaming products. This report examines TCP friendliness, and looks at the differences between UDP, TCP, and their use in RealNetworks and Microsoft with regard to their streaming products. Keywords: TCP (Transmission Control Protocol), UDP (User Datagram Protocol) Table of Contents Abstract 2 Table of Contents 3 DQ1 4 TCP Friendliness 4 DQ2 6 Should streaming stored audio run over UDP or TCP? 6 What transport protocol do RealNetworks use and why? 7 Which protocol does Microsoft streaming products use and why? 8 Conclusion 8 References 9 DQ1 TCP Friendliness The growth in the use of the Internet has resulted in the use of more multimedia components, which require greater network bandwidth and consequently new network considerations. Audio and video as multimedia components require large bandwidth for transmission, and therefore pose a very real threat to overloading the connections and hampering other transmissions in the process. The quagmire has led to the development of a technique to prevent the risk of network collapse through overload. TCP is presently the most popular end-to-end congestion control mechanism in use (Biyani and Martin, 2001). From TCP transmission properties emerged TCP friendly transmission, a connection standard that ensures the integrity and reliability of the network amidst heavy usage for multimedia streaming transmissions. TCP is the most common congestion control mechanism over the Internet. Most of the Internet traffic is TCP based, consequently, the need for congestion control protocols to be TCP friendly is indisputable. Therefore, the rate at which non-TCP flows send data should be as close as possible to the TCP rates, otherwise called TCP friendly (Yang, Kim and Lam, 2000). In summary, TCP friendly flow of streaming media is one that makes similar utilization of the network resources as a standard non-conforming TCP under similar circumstances. Real-time multimedia applications streaming over the internet usually require special network circumstances to avoid congestion, as they may consume large amounts of bandwidth and cause packet drops (Wang, Long, Cheng and Zhang, 2000). TCP friendly flows offer a means of congestion control, allowing applications to make better use of the network, and prevent the uneventful network malfunction that results in the crippling congestive collapse in computer networks. Usually, UDP traffic, mainly for the transmission of stored streaming audio over the Internet, consumes higher than normal bandwidth, which poses a risk to other network connections (Wang et al, 2000). As such, UDP connections result in congestion in the networks, and unfairly interference with initially responsive TCP connections due to the greater load on the network resources. Consequently, UDP, a non-TCP protocol needs to adaptation to bandwidth control mechanisms to make it TCP-friendly, and therefore make similar use of network resources as the more regular TCP connections. There exist a number of congestive friendly mechanisms. For instance, end-to-end TCP friendly congestion control mechanism reduces the load on the network when packet drops occur (Wang et al, 2000). The end-to-end congestion control is useful for both responsive and unresponsive network flows. However, end-to-end TCP friendly congestion control can only detect congestion through delays and loss in data packets, which means that their reaction is usually too late. Alternatives that are more efficient include hop-by-hop congestion control, which are better at avoiding congestion before it occurs (Wang et al, 2000). TCP friendly network flow principally refers to a non-TCP connection, which matches regular TCP flow with regard to bandwidth utilization. An example is UDP, a protocol in wide usage in transmission of high bandwidth multimedia streams over the Internet. Further research into the field of congestion control through the advancement in TCP friendly protocols aims at applications that perform more efficient congestion control, exhibit greater adaptability to network by operating in a broader range of networks, and congestive control algorithms that aim to eliminate Congestive Collapse. DQ2 Should streaming stored audio run over UDP or TCP? Streaming stored audio is transmittable over either User Datagram Protocol (UDP) or Transmission Control Protocol (TCP). When transmitting stored audio over UDP, there is a possibility of better quality as it does not have TCP connection overhead. In addition, UDP stored audio streaming has faster speeds as it makes use of multiple ports for transmission (Choudhry, 2011). However, UDP still requires another UDP or TCP connection to transmit the audio stream. Another problem with UDP audio streams is their inability to circumvent firewalls, Network Access Translation (NAT) and some kinds of routers. In cases where the audio is compressed, the loss of packet data may gravely destroy the quality of the audio to below the minimum acceptable threshold. Compression audio makes it less appropriate for more loss, as compression causes loss in the quality of the audio stream. Further loss in the stream quality therefore degrades the stream further and makes it of very poor quality. One advantage of using TCP connection for stored audio transmission is the guarantee of a higher minimum quality in comparison to the UDP connection. TCP connection also does considerably better in firewall and Network Access Translation situations (NAT) when compared to the UDP connections. In addition, unlike the UDP connection, TCP streaming of stored audio does not need extra channel as it provides control and itself. The major challenge of the TCP stored audio transmission is that it may be slower due to TCP connection management overhead. In addition, it is practically impossible to use TCP connections for the same stream of stored audio (Choudhry, 2011). The fact that each of the transmission methods, TCP or UDP, offers unique benefits and challenges to the user, the choice depends largely on the network situation the user is using. Where there is heavy firewall and NAT hindrances to the network, the TCP connection would be more appropriate. However, in cases where a faster and more consistent transmission of audio over congested networks is desired, a UDP connection would be more appropriate for the transmission of stored audio. What transport protocol do RealNetworks use and why? RealNetworks usually deliver packet data over UDP protocols. However, RealNetworks incorporate the use of RTP (Real-Time Transport Protocol), which synchronizes and provides all the transport features and links the server containing the stored media and the application playing the media. Although RTP primarily runs on UDP, it can also run on TCP connections as well as other non-Internet transport systems. UDP bears the advantage of ensuring synchronized delivery of streaming packets, thus its wide use in delivery of media on multicast networks. RTP protocol also incorporates RTCP (Real-time Control Protocol) and RTSP (Real-time streaming protocol) which provide quality control and media control and manipulation respectively. Which protocol does Microsoft streaming products use and why? Microsoft primarily relies on UDP protocol, although it allows users to switch to TCP (Choudhry, 2011). Microsoft has in place a set of protocols (Multimedia Server protocol, MMS), which ensure transmission of its products to users of both UDP (through MMSU), TCP (through MMST) networks, and HTTP streaming (Microsoft, 2010). Microsoft principally uses UDP connections for more effective delivery of audio streams (Stolarz, 2004). UDP unlike TCP protocols, are less sensitive to network congestions, which result in loss of data packets. In addition, TCP congestion control mechanism results in delays in transmission of the stored audio. TCP is also relatively poor in packet timing, and may cause garbed relays in audio to the receiver, especially where the product under transmission also includes video. However, Microsoft also has a protocol for TCP networks, where the networks do not allow UDP traffic. Conclusion TCP friendly is an umbrella standard for protocol requirements for non-TCP protocols. The standard is ensures the reliability of computer connections. Both Microsoft and RealNetworks rely majorly on UDP connections, as there are more reliable and faster in transmission of both audio and video stored stream s of data. References (DQ1) Biyani, S and Martin, J. 2001. ‘A comparison of TCP-friendly congestion control protocols’. Clemson University. Last accessed March 17, 2012 from http://www.cs.clemson.edu/~jmarty/papers/simd-submit.pdf Wang, Qian, Long, Keping, Cheng, Shiduan, and Zhang, Runtong. 2000. ‘TCP Friendly congestion control schemes in the internet’. Nokia China R&D center. Last accessed March, 18, 2012 from http://www.sics.se/~runtong/11.pdf Yang, Richard, Kim Sik and Lam Simon. 2000. ‘Transient behaviors of TCP friendly congestion protocols’. University of Texas. Last accessed on March 18, 2012 from http://www-net.cs.yale.edu/publications/transient_TR.pdf (DQ2) Choudhry, A. 2011. ‘Streaming Stored Audio’. Akber. Last accessed on March 17, 2012 from http://www.akber.com/streaming-stored-audio Stolarz, D. 2004. ‘Streaming Protocols’. InformIT. Last accessed on March 17, 2012 from http://www.informit.com/articles/article.aspx?p=331397&seqNum=4 Microsoft. 2011. ‘Windows media porting kits: Other windows media technology’. Microsoft.com. Last accessed on March 17, 2012 from http://microsoft.com/windows/windowsmedia/licensing/netprokit.aspx#Top Read More