tailieunhanh - Network Congestion Control Managing Internet Traffic phần 2

có một số khoảng không cho phép chỗ ở của một số lượng ngày càng tăng của khách hàng có nhu cầu băng thông ngày càng tăng trong một thời gian. Mục tiêu của cơ chế kiểm soát tắc nghẽn chỉ đơn giản là sử dụng mạng một cách hiệu quả nhất có thể, đó là, | . WHAT IS CONGESTION 9 and perhaps need special training which means that these networks cost more money. Moreover there is an increased risk of network failures which once again leads to customer complaints. With an overprovisioned network an ISP is prepared for the future - there is some headroom that allows the accommodation of an increasing number of customers with increasing bandwidth demands for a while. The goal of congestion control mechanisms is simply to use the network as efficiently as possible that is attain the highest possible throughput while maintaining a low loss ratio and small delay. Congestion must be avoided because it leads to queue growth and queue growth leads to delay and loss therefore the term congestion avoidance is sometimes used. In today s mostly uncongested networks the goal remains the same - but while it appears that existing congestion control methods have amply dealt with overloaded links in the Internet over the years the problem has now shifted from How can we get rid of congestion to How can we make use of all this bandwidth . Most efforts revolve around the latter issue these days while researchers are still pursuing the same goal of efficient network usage it has become somewhat fashionable to replace congestion control with terms such as high performance networking high speed communication and so on over the last couple of years. Do not let this confuse you - it is the same goal with slightly different environment conditions. This is a very important point as it explains why we need congestion control at all nowadays. Here it is again Congestion control is about using the network as efficiently as possible. These days networks are often overprovisioned and the underlying question has shifted from how to eliminate congestion to how to efficiently use all the available capacity . Efficiently using the network means answering both these questions at the same time this is what good congestion control mechanisms do. The .