【名词&注释】
投资决策(investment decision)、亚里士多德(aristotle)、原发性三叉神经痛(primary trigeminal neuralgia)、消费品(consumer goods)、资源税(resource tax)、分布区(distribution area)、基础上(basis)、一部分(part)、第一支、标识符(identifier)
[单选题]For (1) service, we need a virtual-circuit subnet. Let us see how that works. The idea behind virtual circuits is to avoid having to choose a new (2) for every packet sent. Instead,when a connection is established, a route from the(3) machine to the destination machine is chosen as part of the connection setup and stored in tables inside the (4) . That route is used for all traffic flowing over the connection, exactly the same way that the telephone system works.When the connection is released, the virtual circuit is also terminated. With connection-oriented service, each packet carries an (5) telling which virtual circuit it belongs to.
A. D