简要说明超量工程法提高服务质量的原理。
参考答案：超量工程法是指在网络规划时预留足够的带宽，并限制进入网络的流量，使得任何时候都能获得可接受的QoS。这种方法不需要对IP网络进行改造就能在较大范围内支持实时业务，提供可接受的服务质量。现在有些运营商就采用这种方法组建NGN承载网络，将NGN业务网与Internet业务公用网分开，为NGN业务提供了较为充分的带宽；当进入网络的呼叫数达到一定数量时，就不再允许新的呼叫进入，从而保证进入该网络的呼叫都有足够的带宽，获得可接受的服务质量。
| There has been much speculation about the origin of baseball. In 1907 a special commission decided that the modern game was invented by Abner Doubleday in 1839. One hundred years later the National Baseball Museum was opened to honor Doubleday. Historians, however, disagree about the origin of baseball. Some say that baseball comes from bat-and-ball games of ancient times. It is a matter of record that in the 1700s English boys played a game they called "baseball". Americans have played a kind of baseball since about 1800. At first tile American game had different rules and different names in various parts of the country — "town ball". "rounders", or "one old cat". Youngsters today still play some of these simplified forms of the game. Baseball did not receive a standard set of rules until 1845, when Alexander Cartwright organized the Knicker-bocker Baseball Club of New York City. The rules Cartwright set up for his nine-player team were widely adopted by other clubs and formed the basis of modem baseball. The game was played on a "diamond" infield with the bases 90 feet apart. The first team to score 21 runs was declared the winner. By 1858 the National Association of Baseball Players was formed with 25 amateur teams. The Cincinnati Red Stockings began to pay players in 1869. |
Which of the following is true about the origins of baseball
A．Historians agree that baseball was invented by Abner Doubleday.
B．Baseball, as played in the early 19th century, differed very little from today’s game.
C．As early as the 1700s, English boys played a game called "baseball".
D．The first standard set of baseball rules was established at the turn of the century