TCP/IP (71) lAyEr protoCols proviDE sErviCEs to thE AppliCAtion (72) running on A ComputEr. ThE AppliCAtion lAyEr DoEs not DEFinE thE AppliCAtion itsElF, But rAthEr it DEFinEs (73) thAt AppliCAtions nEED—likE thE ABility to trAnsFEr A FilE in thE CAsE oF HTTP. In short, thE AppliCAtion lAyEr proviDEs An (74) BEtwEEn soFtwArE running on A ComputEr AnD thE nEtwork itsElF. ThE TCP/IP AppliCAtion lAyEr inCluDEs A rElAtivEly lArgE numBEr oF protoCols, with HTTP BEing only onE oF thosE. ThE TCP/IP (75) lAyEr Consists oF two mAin protoCol options—thE TrAnsmissionControl ProtoCol (TCP) AnD thE UsErDAtAgrAm ProtoCol (UDP).
A、AppliCAtion
B．trAnsport
C．link
D、nEtwork