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] 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]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]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]—We need to a time to have a talk,now!—What about tomorrow？I am too busy today.A．put up B.fix up C.use up D.look up

[单选题]We all need (11) ．Doctors say it is good (12) 0ur (13) ．It makes your heart and body strong． And you'll (14) better about yourself． It's best to exercise(15) a week．Twenty minutes each time is enough．There are (16 ways to exercise． You can walk， (1

[单选题]H．ave you played baseball before?We need one more player.____.I like ball games ,no i believe it will be to learn baseball.A．Sometimes B.Not reallC．Never mind D.That's cool

[单选题]We need to [extract]the relevant financial data.A.storeB.saveC.obtainD.revi

[单选题]—Have you played baseball before?We need one more player.— I_______ like ball games, so I belives it will be fun to learn baseball.A．SometinmesB． Not reallyC． Never mindD．That’s cool