Cisco CCNA考试七十九题

dn001 2007-05-31 04:03:32

　　1.What;is;the;correct;order;for;

the;OSI;model?;

　　P=Presentation,;S=Session,;D=Datalink,;

　　Ph=Physical,;T=Transport,;A=;Application,;

　　N=Network;

　　A.;P;S;A;PH;D;N;T;
　　B.;A;P;S;T;N;D;PH
　　C.;PH;D;N;T;A;S;P;
　　D.;P;S;A;T;N;D;PH;

It;is;crucial;you;not;only;memorize;this;

and;know;what;each;layer;does.;

　　2.;What;is;encapsulation?

　　A.;Putting;the;header;on;an;incoming;frame;
　　B.;Putting;a;header;on;an;incoming;segment;
　　C.;Putting;a;header;on;an;outgoing;frame
　　D.;Putting;a;header;on;an;outgoing;bit;

　　This;also;includes;trailers;and;can;be;put;on;segments,;

　packets,;and;frames.;

　　3.;Which;layer;is;most;concerned;with;user;applications?

　　A.;Application
　　B.;Presentation;
　　C.;Network;
　　D.;Physical;

　　4.;Which;of;the;following;is;de-encapsulation?

　　A.;Stripping;the;header;from;a;frame
　　B.;Putting;a;header;on;a;segment;
　　C.;Putting;a;header;on;a;frame;
　　D.;Stripping;a;frame;from;a;link;
　　

This;also;includes;trailers;as;in;question;2.;

　　5.;What;layer;converts;data;into;segments?

　　A.;Application;
　　B.;Presentation;
　　C.;Transport;
　　D.;Physical;

　　
　
　　6.;What;layer;converts;data;into;Packets?

　　A.;Network;
　　B.;Application;
　　C.;Physical;
　　D.;Data;Link;

　

　　7.;What;layer;converts;data;into;Frames?;

　　A.;Application;
　　B.;Physical;
　　C.;Data;Link;
　　D.;Transport;

　　8.;What;layer;converts;data;into;bits?

　　A.;Application;
　　B.;Session;
　　C.;Data;Link;
　　D.;Physical;

　　

　　All;of;the;layers;need;to;convert;data;into;something;that;

　　they;can;pass;down;to;the;next;level,;with;the;exception;of;

　　the;Application;layer;which;hands;data;to;the;Presentation;layer.

　　The;Presentation;layer;encrypts,;and;compresses;

　　before;sending;it;to;

　　the;Session;layer;for;it;s;first;conversion.;

　　9.;Which;layer;is;most;concerned;with;getting;data

　　from;the;beginning;to;the;final;destination?;
　　A.;Application;
　　B.;Presentation;
　　C.;Session;
　　D.;Transport

　　The;transport;layer;is;most;concerned;with;reliable;transportation;

　　from;one;end;to;the;other.;

　　10.;Which;of;the;following;is;not;a;part;

　　of;the;Session;layer?;

　　A.;Establishing;a;session;
　　B.;Ensuring;error;free;segments;
　　C.;Ending;a;session

　　D.;Keeping;the;sender;and;receiver;from;sending;a;message;

　　at;the;same;time; That;is;the;job;of;the;Transport;layer.;

　　11.;Which;of;the;following;is;not;a;job;

　for;the;presentation;layer?;Choose;2

　　A.;Data;representation;
　　B.;Compression;
　　C.;Dialog;management;
　　D.;Transmission;
　　E.;Encryption;

　　C;is;handled;by;the;session;layer,;and;D;is;handled;

　　by;the;Transport;layer;

　　12.;What;does;Peer;to;Peer;communication;involve?;

　　A.;Each;layer;communication;with;the;layer;below;it;
　　B.;Each;layer;communication;with;layer;above;it;
　　C.;Each;layer;communicating;with;adjacent;layer;in;another;system;
　　D.;Each;layer;communication;with;it;s;corresponding;layer;in;

　　another;system;

　　Answer;D.

　　Answer;C;sounds;correct;also,;but;adjacent;

　　and;corresponding;are;two;different;things.;

　　The;session;layer;can;only;communicate;with;the;session;

　　layer;in;another;system;for;example.;

　　13.;Why;does;the;industry;use;a;layered;model?;

　　Choose;all;correct;

　　A.;When;you;enhance;one;layer;it;doesn;t;affect;the;other;layers;
　　B.;Design;and;development;can;be;made;in;a;modular;fashion;
　　C.;Network;operations;can;be;simplified;
　　D.;Troubleshooting;can;be;simplified.;

　
14.;Which;two;of;the;following;are;not;

;from;the;physical;layer?;

　　A.;SDLC
　　B.;V.35;
　　C.;HSSI;
　　D.;ISDN;
　　E.;RS-232;

　　Answer;A;D.;