Consider the scenario shown below, with four different servers connected to four different clients over four three-hop paths. The four pairs share a common middle hop with a transmission capacity of R = 100 Mbps. The four links from the servers to the shared link have a transmission capacity of RS = 20 Mbps. Each of the four links from the shared middle link to a client has a transmission capacity of RC = 100 Mbps. Show You might want to review Figure 1.20 in the text before answering the following questions Question List1. What is the maximum achievable end-end throughput (in Mbps) for each of four client-to-server pairs, assuming that the middle link is fairly shared (divides its transmission rate equally)? 2. Which link is the bottleneck link? Format as Rc, Rs, or R 3. Assuming that the servers are sending at the maximum rate possible, what are the link utilizations for the server links (RS)? Answer as a decimal 4. Assuming that the servers are sending at the maximum rate possible, what are the link utilizations for the client links (RC)? Answer as a decimal 5. Assuming that the servers are sending at the maximum rate possible, what is the link utilizations for the shared link (R)? Answer as a decimal Solution1. The maximum achievable end-end throughput is the capacity of the link with the minimum capacity, which is 20 Mbps 2. The bottleneck link is the link with the smallest capacity between RS, RC, and R/4. The bottleneck link is Rs. Bandwidth is the data transfer capacity of a computer network in bits per second (Bps). The term may also be used colloquially to indicate a person's capacity for tasks or deep thoughts at a point in time. Key Takeaways
Understanding BandwidthBandwidth is a measure of how much information a network, a group of two or more devices that communicate between themselves, can transfer. Data moves from A to B just as water flows through pipes from a supply point to our faucets. The volume that's transported, the bandwidth, varies, impacting how effectively a transmission medium, such as an Internet connection, operates. Internet service providers (ISPs) typically denote bandwidth speeds in millions of bits per second (Bps), or megabits (Mbps), and billions of Bps, or gigabits (Gbps). Generally speaking, the higher the bandwidth, the quicker a computer downloads information from the Internet, including emails or streamed movies. The U.S. Federal Communications Commission (FCC) defines broadband Internet speeds as connections with a bandwidth of 25 Mbps for downloads and three Mbps for uploads. Providers state the bandwidth measurement to customers, although the number they quote may not always reflect what a customer actually gets. The connection could have a bottleneck where one network is limited by the lowest speed going to several computers at once. More computers connected to the same bandwidth speed slow down the bandwidth for everyone who shares the same connection. Recording BandwidthAny computer can measure the amount of bandwidth it actually receives at any given time. Special websites, or the ISP, are able to calculate the bandwidth by sending a file through the connection and then waiting for the information to return. Bandwidth RequirementsThe amount of bandwidth required to surf the web seamlessly depends on the task the user wishes to undertake. For instance, an instant messaging conversation may use 1,000 bits, or one kilobit, per second in bandwidth. A voice-over conversation, in which someone's voice transmits through computer connections, meanwhile, typically uses 56 kilobits per second (Kbps). Moving further up the scale, standard-definition video takes one Mbps, while HDX video quality, one of the highest standards on video-sharing services, takes more than seven Mbps for downloading. History of BandwidthSince 1994, the Internet has transformed from a niche technology, serving mainly to interconnect laboratories engaged in government research, to a key part of everyday life. In 1995, 0.68% of the world's population reportedly had access to the Internet. Fast-forward to 2019, and over half of the globe was connected. People now depend on the Internet to communicate, purchase goods, earn an income, gain access to information, and entertain themselves. Over the years, the technology has become more content-heavy, sophisticated, and populated, meaning the amount of bandwidth required to use it effectively has increased substantially. Fast FactIn 2019, video accounted for over 60% of the total downstream volume of traffic on the Internet, according to Sandvine's Global Internet Phenomena Report. From May 2018 to May 2019, the average Internet speed surged 20.65% to 11.03 Mbps. Ookla, a company that specializes in Internet testing and analysis, claimed that Singapore had the best bandwidth capabilities in the world in Sept. 2020, with online speeds of 226.60 Mbps—far more more than the 161.14 Mbps registered in the United States. The top countries in the world, and the top states, continue to increase their bandwidths as more users and more devices connect to networks. What is the transmission capacity of a network?Transmission capacity (TC) is a performance metric for wireless networks that measures the spatial intensity of successful transmissions per unit area, subject to a constraint on the permissible outage probability (where outage occurs when the SINR at a receiver is below a threshold).
What is data transmission in computer network?Data transmission is the transfer of data from one digital device to another. This transfer occurs via point-to-point data streams or channels. These channels may previously have been in the form of copper wires but are now much more likely to be part of a wireless network.
What is computer network capacity?Network capacity is the maximum amount of data that can be reliably transferred between different locations over a network.
What is the capacity of transmit?Transmission Capacity means the volume of traffic capable of being transmitted using the Frequency as measured from time to time.
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