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.

空白（1）处应选择（）

[单选题]F．or (71) 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 (72) for every packet sent. Instead, when a connection is established, a route from the (73)machine to

[单选题] For （71） service, we need a virtual-circuit subnet. Let us see how that works. Theidea behind virtual circuits is to avoid having to choose a new （72） for every packet sent.Instead, when a connection is established, a route from the （73） machine to

[单选题]Weneedachairman________.A．)forwhomeveryonehasconfidenceB)inwhomeveryonehasconfidenceC．)whoeveryonehasconfidenceofD)whomeveryonehasconfidenceon

[主观题]Weneedtocreateeducationstandardsthatprepareournextgenerationwhowillbe_______withanevenmorecompetitivemarket

[单选题]We need the clean shipped bills of （　） in complete set issued toorder and blank endorsed marked “freight paid”A . loadingB . ladingC . inspectingD . packing

[单选题]When we use VolP service，the voice packets over the Internet arrive at their destination in a（ ） stream.A．burst B.delayed C.interrupted D.continuous

[单选题]We are at your service. Don’t to turn to us if you have any further problems.A． beg B. hesitate C. desire D. seek

Nature provides us with we need: the air we breathe, the water we drink, and the

1　　　　 We need to train ourselves to actively take part in the learning process.

It is my firm belief that not only do we all need nature, but we all seek nature