If two communicating entities are in different hosts connected by a network，there is a risk that PDUs will not arrive inthe order inwhich theywere sent ， becausethey may traverse(70)paths through the network. If each PDUs is given a uniquenumber，andnumbersareassigned(71)，thenit isa logicallysimpletaskforthereceivingentityto reorder(72 )PDUsonthebasisofsequence number.Aproblem with this scheme is that，with a(73)sequence number field， sequence number will repeat.Evidently ， the maximumsequence numbermustbe(74)thanthemaximumnumber ofPDUsthatcouldbe outstandingat anytime. （70）A.same B.different C.single D.Unique （71）A.randomly B.equally C. uniformly D. Sequentially （72）A.received B.sent C.transmitting D.Forwarding （73）A.various B.diverse C.finite D.infinite （74）A.smaller B.greater C.less D.More
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