CCNA 1 v7 Modules 4 – 7 Ethernet Concepts Exam Answers PDF

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Ethernet Concepts Exam Answers...

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Introduction to Networks ( Version 7.00) – Modules 4 – 7: Ethernet Concepts Exam 1. What is the purpose of the OSI physical layer? c ont r ol l i ngaccesst omedi a  transmitting bits across the local media  per f or mi nger r ordet ect i ononr ecei v edf r ames e xc hangi ngf r amesbet weennodesov erphy si cal net wor kmedi a 2. Why are two strands of fiber used for a single fiber optic connection?  Thet wost r andsal l owt hedat at ot r av el f orl ongerdi s t anceswi t houtdegr adi ng.  The ypr ev entcr osst al kf r om causi ngi nt er f er enceont heconnect i on.  The yi ncr easet hespeedatwhi cht hedat acant r avel .  They allow for full-duplex connectivity. 3. Which characteristic describes crosstalk? t hedi st or t i onoft henet wor ksi gnalf r om fluor escentl i ght i ng  the distortion of the transmitted messages from signals carried in adjacent wires t heweak eni ngoft henet wor ksi gnal overl ongcabl el engt hs t hel ossofwi r el esssi gnal overexcessi v edi st ancef r om t heaccesspoi nt 4. Which procedure is used to reduce the effect of crosstalk in copper cables? r equi r i ngpr opergr oundi ngconnect i ons  twisting opposing circuit wire pairs together  wr appi ngt hebundl eofwi r eswi t hmet al l i cshi el di ng  des i gni ngacabl ei nf r ast r uct ur et oav oi dcr osst al ki nt er f er ence a v oi di ngshar pbendsdur i ngi nst al l at i on 5. Match the situation with the appropriate use of network media.

6. A network administrator is measuring the transfer of bits across the company backbone for a mission critical financial application. The administrator notices that the network throughput appears lower than the bandwidth expected. Which three factors could influence the differences in throughput? (Choose three.)  the amount of traffic that is currently crossing the network t hesophi st i cat i onoft heencapsul at i onmet hodappl i edt ot hedat a  the type of traffic that is crossing the network  the latency that is created by the number of network devices that the data is crossing t hebandwi dt hoft heWANconnect i ont ot heI nt er net t her el i abi l i t yoft hegi gabi tEt her neti nf r ast r uct ur eoft hebackbone Explanation: Thr oughputusual l ydoesnotmat c ht hespeci fi edbandwi dt hofphysi cal l i nks duet omul t i pl ef act or s.Thesef act or si ncl ude,t heamountoft r affic,t ypeoft r affic,andl at ency cr eat edbyt henet wor kdevi cest hedat ahast ocr oss. 7.Whatar et wochar act er i st i csoffiber opt i ccabl e?( Chooset wo. )  It is not affected by EMI or RFI.  Ea chpai rofcabl esi swr appedi nmet al l i cf oi l . I tcombi nest het echni queofcancel l at i on,shi el di ng,andt wi st i ngt opr ot ectdat a. I tt ypi cal l ycont ai ns4pai r soffiber opt i cwi r es.  It is more expensive than UTP cabling is. Explanation: Fi ber opt i ccabl i ngsuppor t shi gherbandwi dt ht hanUTPf orl ongerdi st ances. Fi beri si mmunet oEMIandRFI ,butcost smor e,r equi r esmor eski l l t oi nst al l ,andr equi r esmor e saf et ypr ecaut i ons. 8.Whati sapr i mar yr ol eoft hePhysi call ayeri nt r ansmi t t i ngdat aont henet wor k?  create the signals that represent the bits in each frame on to the media  pr ovi dephys i cal addr essi ngt ot hedevi ces  de t er mi net hepat hpacket st aket hr ought henet wor k c ont r ol dat aaccesst ot hemedi a Explanation: TheOSIphysi call ay erpr ovi dest hemeanst ot r anspor tt hebi t st hatmakeupa f r ameacr osst henet wor kmedi a.Thi sl ay eraccept sacompl et ef r amef r om t hedat al i nkl ay er andencodesi tasaser i esofsi gnal st hatar et r ansmi t t edt ot hel ocalmedi a. 9. With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?  the magnetic field around the adjacent pairs of wire t heuseofbr ai dedwi r et oshi el dt headj acentwi r epai r s t her eflect i onoft heel ect r i cal wavebackf r om t hef arendoft hecabl e t hecol l i si oncausedbyt wonodest r yi ngt ouset hemedi asi mul t aneousl y Explanation: Cr osst al ki sat ypeofnoi se,ori nt er f er encet hatoccur swhensi gnal t r ansmi ssi onononewi r ei nt er f er eswi t hanot herwi r e.Whencur r entflowst hr oughawi r ea magnet i cfiel di spr oduced.Thepr oducedmagnet i cfiel dwi l l i nt er f acet hesi gnal car r i edi nt he adj acentwi r e.

10. Refer to the graphic. What type of cabling is shown?

 STP  UTP c oax  fiber

Explanation: Net wor kcabl i ngi ncl udedi ffer entt ypesofcabl es:  UTPc abl econsi st soff ourpai r sofcol or codedwi r est hathav ebeent wi st edt oget her andt henencasedi naflexi bl epl ast i csheat h.  STPc abl eusesf ourpai r sofwi r es,eachwr appedi naf oi l shi el d,whi char et hen wr appedi nanov er al l met al l i cbr ai dorf oi l .  Coax i al cabl eusesacopperconduct orandal ayerofflexi bl epl ast i ci nsul at i onsur r ounds t hecopperconduct or .  Fi bercabl ei saflexi bl e,ext r emel yt hi n,t r anspar entst r andofgl asssur r oundedbypl ast i c i nsul at i on. 11. In addition to the cable length, what two factors could interfere with the communication carried over UTP cables? (Choose two.)  crosstalk  bandwi dt h s i z eoft henet wor k s i gnal modul at i ont echni que  electromagnetic interference Explanation: Coppermedi ai swi del yusedi nnet wor kcommuni cat i ons.However ,copper medi ai sl i mi t edbydi st anceandsi gnal i nt er f er ence.Dat ai st r ansmi t t edoncoppercabl esas el ect r i cal pul ses.Theel ect r i cal pul sesar esuscept i bl et oi nt er f er encef r om t wosour ces:  Electromagnetic interference (EMI) or radio frequency interference (RFI) –EMIandRFIsi gnal scandi st or tandcor r uptt hedat asi gnal sbei ngcar r i edby coppermedi a.  Crosstalk –Cr osst al ki sadi st ur bancecausedbyt heel ect r i cormagnet i cfiel dsofa si gnal ononewi r ei nt er f er i ngwi t ht hesi gnal i nanadj acentwi r e. 12. Refer to the graphic. What type of cabling is shown?

 STP  UTP c oax  fi ber

13. Which two devices commonly affect wireless networks? (Choose two.)  Bl ur aypl ay er s  homet heat er s  cordless phones  microwaves i ncandescentl i ghtbul bs e xt er nal har ddr i ves Explanation: Radi oFr equencyI nt er f er ence( RFI )i st hei nt er f er encet hati scausedbyr adi o t r ansmi t t er sandot herdevi cest hatar et r ansmi t t i ngi nt hesamef r equency . 14. Which two statements describe the services provided by the data link layer? (Choose two.) I tdefinest heendt oenddel i ver yaddr essi ngscheme. I tmai nt ai nst hepat hbet weent hesour ceanddest i nat i ondevi cesdur i ngt hedat a t r ansmi ssi on.  It manages the access of frames to the network media. I tpr ovi desr el i abl edel i v er yt hr oughl i nkest abl i shmentandflowcont r ol . I tensur est hatappl i cat i ondat awi l lbet r ansmi t t edaccor di ngt ot hepr i or i t i zat i on.  It packages various Layer 3 PDUs into a frame format that is compatible with the network interface. Explanation: Thedat al i nkl ay eri sdi vi dedi nt ot wosubl ay er s,namel yLogi cal Li nkCont r ol ( LLC)andMedi aAccessCont r ol ( MAC) .LLCf or msaf r amef r om t henet wor kl ay erPDUi nt oa f or matt hatconf or mst ot her equi r ement soft henet wor ki nt er f aceandmedi a.Anet wor kl ay er PDUmi ghtbef orI Pv4orI Pv6.TheMACsubl ayerdefinest hemedi aaccesspr ocesses per f or medbyt hehar dwar e.I tmanagest hef r ameaccesst ot henet wor kmedi aaccor di ngt ot he phys i cal si gnal i ngr equi r ement s( coppercabl e,fiberopt i c,wi r el ess,et c. ) 15. What is the function of the CRC value that is found in the FCS field of a frame?  to verify the integrity of the received frame t over i f yt hephysi cal addr essi nt hef r ame t over i f yt hel ogi caladdr essi nt hef r ame t ocomput et hechecksum headerf ort hedat afiel di nt hef r ame 16. What is contained in the trailer of a data-link frame? l ogi cal addr ess

 ph ys i cal addr ess  da t a  error detection

17. Which statement describes a characteristic of the frame header fields of the data link layer?  The yal l i ncl udet heflowcont r ol andl ogi cal connect i onfiel ds.  Et her netf r ameheaderfiel dscont ai nLay er3sour ceanddest i nat i onaddr esses.  They vary depending on protocols.  The yi ncl udei nf or mat i ononuserappl i cat i ons . Explanation: Al ldat al i nkl ay erpr ot ocol sencapsul at et heLayer3PDUwi t hi nt hedat afiel dof t hef r ame.Howev er ,t hest r uct ur eoft hef r ameandt hefiel dst hatar econt ai nedi nt heheader v ar yaccor di ngt ot hepr ot ocol .Di ffer entdat al i nkl ayerpr ot ocol smayusedi ffer entfiel ds,l i ke pr i or i t y/ qual i t yofser vi ce,l ogi cal connect i oncont r ol ,physi cal l i nkcont r ol ,flowcont r ol ,and congest i oncont r ol . 18. A network team is comparing physical WAN topologies for connecting remote sites to a headquarters building. Which topology provides high availability and connects some, but not all, remote sites?  mes h  partial mesh  hubands pok e  poi nt t opoi nt Explanation: Par t i almesht opol ogi espr ovi dehi ghavai l abi l i t ybyi nt er connect i ngmul t i pl e r emot esi t es ,butdonotr equi r eaconnect i onbet weenal l r emot esi t es .Amesht opol ogy r equi r espoi nt t opoi ntl i nkswi t hev er ys yst em bei ngconnect edt oever yot hersy st em.Apoi nt t opoi ntt opol ogyi swher eeachdevi cei sconnect edt ooneot herdevi ce.Ahubandspokeuses acent r al devi cei nast art opol ogyt hatconnect st oot herpoi nt t opoi ntdevi ces. 19. Which two fields or features does Ethernet examine to determine if a received frame is passed to the data link layer or discarded by the NIC? (Choose two.)  aut oMDI X  CEF  Frame Check Sequence  minimum frame size s our ceMACaddr ess 20. Which media communication type does not require media arbitration in the data link layer?  de t er mi ni st i c  hal f dupl ex  full-duplex c ont r ol l edaccess Explanation: Hal f dupl excommuni cat i onoccur swhenbot hdevi cescanbot ht r ansmi tand r ecei veont hemedi um butcannotdososi mul t aneousl y .Ful l dupl excommuni cat i onoccur s whenbot hdevi cescant r ansmi tandr ecei v eont hemedi um att hesamet i meandt her ef or e doesnotr equi r emedi aar bi t r at i on.Hal f dupl excommuni cat i oni st ypi cal l ycont ent i onbased, wher eascont r ol l ed( det er mi ni st i c)accessi sappl i edi nt echnol ogi eswher edevi cest aket ur nst o accesst hemedi um. 21. Which statement describes an extended star topology?

 End devices connect to a central intermediate device, which in turn

connects to other central intermediate devices.  Endde vi cesar econnect edt oget herbyabusandeachbusconnect st oacent r al

i nt er medi at edevi ce.  Eac hends yst em i sconnect edt oi t sr espect i venei ghborvi aani nt er medi at edevi ce.  Al lendandi nt er medi at edevi cesar econnect edi nachai nt oeachot her .

Explanation: I nanext endedst art opol ogy ,cent r ali nt er medi at edevi cesi nt er connectot her st art opol ogi es. 22. What is a characteristic of the LLC sublayer? I tpr ovi dest hel ogi cal addr essi ngr equi r edt hati dent i fiest hedevi ce. I tpr ovi desdel i mi t at i onofdat aaccor di ngt ot hephys i cal si gnal i ngr equi r ement soft he medi um.  It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media. I tdefinessof t war epr ocessest hatpr ovi deser vi cest ot hephysi cal l ay er . 23. What are three ways that media access control is used in networking? (Choose three.)  Ethernet utilizes CSMA/CD.  Media access control provides placement of data frames onto the media.  Co nt ent i onbasedaccessi sal soknownasdet er mi ni st i c.  802. 11ut i l i z esCSMA/ CD.  Data link layer protocols define the rules for access to different media.  Ne t wor kswi t hcont r ol l edaccesshav er educedper f or manceduet odat acol l i si ons. 24. During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network?  AnI Paddr essi sadded.  Thel ogi caladdr essi sadded.  The physical address is added.  Thepr ocesspor tnumberi sadded. Explanation: TheEt her netf r amei ncl udest hesour ceanddest i nat i onphysi caladdr ess .The t r ai l eri ncl udesaCRCval uei nt heFr ameCheckSequencefiel dt oal l owt her ecei vi ngdevi cet o det er mi nei ft hef r amehasbeenchanged( haser r or s )dur i ngt het r ansmi ssi on. 25. What three items are contained in an Ethernet header and trailer? (Choose three.) s our ceI Paddr ess  source MAC address  des t i nat i onI Paddr ess  destination MAC address  error-checking information Explanation: Lay er2header scont ai nt hef ol l owi ng:  Fr amest ar tandst opi ndi cat orflagsatt hebegi nni ngandendofaf r ame  Addr essi ng–f orEt her netnet wor kst hi spar toft heheadercont ai nssour ceand dest i nat i onMACaddr esses T ypefiel dt oi ndi cat ewhatLay er3pr ot ocol i sbei ngused  Er r ordet ect i ont odet er mi nei ft hef r amear r i vedwi t houter r or

26. What type of communication rule would best describe CSMA/CD?  access method  fl owcont r ol  mes sageencapsul at i on  mes sageencodi ng Explanation: Car r i ersensemul t i pl eaccesscol l i si ondet ect i on( CSMA/ CD)i st heaccess met hodusedwi t hEt her net .Theaccessmet hodr ul eofcommuni cat i ondi ct at eshowanet wor k devi cei sabl et opl aceasi gnal ont hecar r i er .CSMA/ CDdi ct at est hoser ul esonanEt her net net wor kandCSMA/ CAdi ct at est hoser ul esonan802. 11wi r el essLAN. 27. Which three basic parts are common to all frame types supported by the data link layer? (Choose three.)  header t ypefiel d  MTUs i z e  data  trailer  CRCv al ue Explanation: Thedat al i nkpr ot ocoli sr esponsi bl ef orNI Ct oNI Ccommuni cat i onswi t hi nt he samenet wor k .Al t hought her ear emanydi ffer entdat al i nkl ayerpr ot ocol st hatdescr i bedat al i nk l ayerf r ames,eachf r amet ypehast hr eebasi cpar t s:  He ader  Dat a T r ai l er 28. Which statement is true about the CSMA/CD access method that is used in Ethernet?  Whenade vi cehear sacar r i ers i gnal andt r ansmi t s,acol l i si oncannotoccur .  Aj ammi ngsi gnal causesonl ydevi cest hatcausedt hecol l i si ont oex ecut eabackoff al gor i t hm.  All network devices must listen before transmitting.  De vi cesi nvol v edi nacol l i si ongetpr i or i t yt ot r ansmi taf t ert hebackoffper i od. 29. What is the auto-MDIX feature on a switch? t heaut omat i cconfigur at i onofani nt er f acef or10/ 100/ 1000Mb/ soper at i on  the automatic configuration of an interface for a straight-through or a crossover Ethernet cable connection t heaut omat i cconfigur at i onoff ul l dupl exoper at i onov erasi ngl eEt her netcopperor opt i cal cabl e t heabi l i t yt ot ur naswi t chi nt er f aceonoroffaccor di ngl yi fanact i veconnect i oni s det ect ed Explanation: Theaut oMDI Xenabl esaswi t cht ouseacr ossoverorast r ai ght t hr ough Et her netcabl et oconnectt oadevi cer egar dl essoft hedevi ceont heot herendoft he connect i on. 30. Refer to the exhibit. What is the destination MAC address of the Ethernet frame as it leaves the web server if the final destination is PC1?

 00602F3A07AA  00602F3A07BB  00-60-2F-3A-07-CC  00602F3A07DD

Explanation: Thedest i nat i onMACaddr essi susedf orl ocal del i v er yofEt her netf r ames.The MAC( Lay er2)addr esschangesateachnet wor ks egmental ongt hepat h.Ast hef r amel eav es t hewebser ver ,i twi l l bedel i ver edbyusi ngt heMACaddr essoft hedef aul tgat eway . 31. A Layer 2 switch is used to switch incoming frames from a 1000BASE-T port to a port connected to a 100Base-T network. Which method of memory buffering would work best for this task?  por t basedbuffer i ng l ev el 1cachebuffer i ng  shared memory buffering  fi x edconfigur at i onbuffer i ng Explanation: Wi t hshar edmemor ybuffer i ng,t henumberoff r amesst or edi nt hebufferi s r est r i ct edonl ybyt heoft heent i r ememor ybufferandnotl i mi t edt oasi ngl epor tbuffer .Thi s per mi t sl ar gerf r amest obet r ansmi t t edwi t hf ewerdr oppedf r ames .Thi si si mpor t antt o as ymmet r i cswi t chi ng,whi chappl i est ot hi sscenar i o,wher ef r amesar ebei ngexc hanged bet weenpor t sofdi ffer entr at es.Wi t hpor t basedmemor ybuffer i ng,f r amesar est or edi nqueues t hatar el i nkedt ospeci fici ncomi ngandout goi ngpor t smaki ngi tpossi bl ef orasi ngl ef r amet o del ayt het r ansmi ssi onofal l t hef r amesi nmemor ybecauseofabus ydest i nat i onpor t .Level 1 cachei smemor yusedi naCPU.Fi x edconfigur at i onr ef er st ot hepor tar r angementi nswi t ch har dwar e. 32.Whatar et woexampl esoft hecut t hr oughswi t chi ngmet hod?( Chooset wo. ) s t or eandf or war dswi t chi ng  fast-forward switching  CRCs wi t chi ng  fragment-free switching  QOSs wi t chi ng

Explanation: St or eandf or war dswi t chi ngaccept st heent i r ef r ameandper f or mser r or checki ngusi ngCRCbef or ef or war di ngt hef r ame.St or eandf or war di sof t enr equi r edf orQOS anal ysi s.Fast f or war dandf r agment f r eear ebot hvar i at i onsoft hecut t hr oughswi t chi ngmet hod wher eonl ypar toft hef r amei sr ecei vedbef or et heswi t chbegi nst of or war di t . 33.Whi chf r amef or war di ngmet hodr ecei vest heent i r ef r ameandper f or msaCRCcheck t odet ecter r or sbef or ef or war di ngt hef r ame? c ut t hr oughswi t chi ng  store-and-forward switching f r agment f r eeswi t chi ng f ast f or war ds wi t chi ng Explanation: Fast f or war dandf r agment f r ees wi t chi ngar ev ar i at i onsofcut t hr ough swi t chi ng,whi chbegi nst of or war dt hef r amebef or et heent i r ef r amei sr ecei ved. 34. What is the purpose of the FCS field in a frame? t oobt ai nt heMACaddr essoft hesendi ngnode t over i f yt hel ogi caladdr essoft hesendi ngnode t ocomput et heCRCheaderf ort hedat afiel d  to determine if errors occurred in the transmission and reception Explanation: TheFCSfiel di naf r amei susedt odet ectanyer r or si nt het r ansmi ssi onand r ecei ptofaf r ame.Thi si sdonebycompar i ngt heCRCval uewi t hi nt hef r ameagai nsta comput edCRCv al ueoft hef r ame.I ft het wov al uesdonotmat ch,t hent hef r amei sdi scar ded. 35. Which switching method has the lowest level of latency? c ut t hr ough s t or eandf or war d f r agment f r ee  fast-forward Explanation: Fast f or war dswi t chi ngbegi nst of or war daf r ameaf t err eadi ngt hedest i nat i on MACaddr ess ,r esul t i ngi nt hel owestl at ency .Fr agment f r eer eadst hefir st64byt esbef or e f or war di ng.St or eandf or war dhast hehi ghestl at encybecausei tr eadst heent i r ef r amebef or e begi nni ngt of or war di t .Bot hf r agment f r eeandf ast f or war dar et ypesofcut t hr oughswi t chi ng. 36. A network administrator is connecting two modern switches using a straight-through cable. The switches are new and have never been configured. Which three statements are correct about the final result of the connection? (Choose three.)  The link between the switches will work at the fastest speed that is supported by both switches.  The link between switches will work as full-duplex. I fbot hswi t chessuppor tdi ffer entspeeds,t heywi l leachwor katt hei rownf ast estspeed.  The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable.  Thec onnect i onwi l lnotbepossi bl eunl esst headmi ni st r at orc hangest hecabl et oa cr ossov ercabl e.  Thedupl excapabi l i t yhast obemanual l yconfigur edbecausei tcannotbenegot i at ed. Explanation: Moder ns wi t chescannegot i at et owor ki nf ul l dupl exmodei fbot hswi t chesar e capabl e.Theywi l l negot i at et owor kusi ngt hef ast estpossi bl espeedandt heaut oMDI Xf eat ur e i senabl edbydef aul t ,soacabl echangei snotneeded.

37. Which advantage does the store-and-forward switching method have compared with the cut-through switching method? c ol l i si ondet ect i ng  frame error checking f ast erf r amef or war di ng f r amef or war di ngusi ngI Pv4Lay er3and4i nf or mat i on Explanation: Aswi t chusi ngt hest or eandf or war dswi t chi ngmet hodper f or msaner r orcheck onani ncomi ngf r amebycompar i ngt heFCSv al ueagai nsti t sownFCScal cul at i onsaf t ert he ent i r ef r amei sr ec...