ΛΥΚΕΙΟ ΠΑΡΑΛΙΜΝΙΟΥ ΣΧΟΛΙΚΗ ΧΡΟΝΙΑ: ΓΡΑΠΤΕΣ ΠΡΟΑΓΩΓΙΚΕΣ ΕΞΕΤΑΣΕΙΣ ΜΑΪΟΥ-IOYNIOY 2014 ΤΑΞΗ: Β ΗΜΕΡΟΜΗΝΙΑ: 13/06/2014

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1 ΛΥΚΕΙΟ ΠΑΡΑΛΙΜΝΙΟΥ ΣΧΟΛΙΚΗ ΧΡΟΝΙΑ: ΓΡΑΠΤΕΣ ΠΡΟΑΓΩΓΙΚΕΣ ΕΞΕΤΑΣΕΙΣ ΜΑΪΟΥ-IOYNIOY 2014 ΤΑΞΗ: Β ΗΜΕΡΟΜΗΝΙΑ: 13/06/2014 ΜΑΘΗΜΑ: Δίκτυα CISCO ΔΙΑΡΚΕΙΑ ΕΞΕΤΑΣΗΣ: 2 ΩΡΕΣ ΩΡΑ: 7:45 9:45 Όνομα Μαθητή/τριας:... Τμήμα:... Αρ.... Οδηγίες: α) Επιτρέπεται η χρήση μη προγραμματιζόμενης υπολογιστικής μηχανής που φέρει τη σφραγίδα του σχολείου. β) Να γράφετε με μελάνι μπλέ (τα σχήματα μπορείτε να τα κάνετε με μολύβι). γ) Δεν επιτρέπεται η χρήση διορθωτικού υγρού ή διορθωτικής ταινίας. δ) Σε όλες τις ερωτήσεις να φαίνεται ο τρόπος απάντησης σας. Ορθές απαντήσεις χωρίς την παρουσίαση της απαιτούμενης αιτιολόγησης δεν θα λαμβάνονται υπόψη. ε) Να συμμορφώνεστε πρόθυμα με τις οδηγίες των επιτηρητών. στ) Η ΔΟΛΙΕΥΣΗ ΤΙΜΩΡΕΙΤΑΙ ΑΥΣΤΗΡΑ Το εξεταστικό δοκίμιο αποτελείται από δύο μέρη, το ΜΕΡΟΣ Α και το ΜΕΡΟΣ Β. Το εξεταστικό δοκίμιο αποτελείται από επτά (7) σελίδες. ΜΕΡΟΣ Α : Απαντήστε όλες τις ερωτήσεις βάζοντας σε κύκλο το αντίστοιχο γράμμα (κάθε ερώτηση έχει μία μόνο σωστή απάντηση). Κάθε ερώτηση βαμολογείται με 1/ During the encapsulation process, data is broken down by the transport layer into: a. packets b. segments c. data bits d. frames 2. Which of the following physical topologies connects all cables to a central point of concentration? a. ring b. star c. mesh d. bus 3. Bandwidth is commonly measured in: a. GHzps b. Mbps c. Nbps d. MHzps 4. Which specialized equipment is used to make a physical connection from a PC to a network? a. router b. switch c. CD Rom d. network interface card Σελίδα 1 από 7

2 5. Which of the following is the official name for the address assigned to each network interface card (NIC) by its manufacturer? a. NIC address b. MAC address c. IP address d. Source Address 6. Which device connects a computer with an analog telephone line, providing modulation/demodulation of incoming/outgoing data? a. NIC b. CSU/DSU c. router d. modem e. telco switch 7. Which of the following is a benefit of wireless networks when compared to wired networks? a. higher data speeds b. better security c. mobility d. less expensive NIC cards e. no transceivers required 8. Which device is used to connect LANs that are geographically separated? a. hub b. bridge c. router d. repeater 9. Which is an application layer protocol? a. IP b. UDP c. TCP d. HTTP 10. What condition is described when transmission signals from one wire pair affect another wire pair? a. resistance mismatch b. jitter c. crosstalk d. attenuation 11. Which data packaging type is created at the data link layer during the data encapsulation process? a. packets b. segments c. data bits d. frames 12. Which type of cable has the color of the wires in pins #1 and #2 on one end appear on the other end at pins #3 and #6, and vice-versa? a. rollover cable b. straight-through cable c. crossover cable d. console cable 13. Which of the following cable tests verifies that all eight wires are connected to the correct pins on both ends of the cable? a. cable length b. insertion loss c. near-end crosstalk (NEXT) d. wire map test 14. Why would fiber optic installations be favored over copper between buildings? a. cheaper installation b. larger media c. no electrical interference d. easier termination and installation 15. What is the most widely used LAN technology? a. FDDI b. coaxial c. Ethernet d. token-ring e. ADSL 16. Which OSI layer covers physical media? a. Layer 1 b. Layer 2 c. Layer 3 d. Layer 4 e. Layer 5 f. Layer 6 Σελίδα 2 από 7

3 17. Which of the following can be determined by using the ping command? a. the number of routers between the source and destination device b. the IP address of the router nearest the destination device c. the average time it takes a packet to reach the destination and for the response to return to the source d. the average time it takes each router in the path between source and destination to respond 18. Which of the following is a benefit of peerto-peer networks? a. centralized security b. very scalable c. no centralized equipment required d. centralized control of assets 19. In which of the following situations would a straight-through cable be used? a. router to router b. router to PC c. PC to switch d. switch to switch 20. Which layer of the OSI model addresses cable and connector type? a. application b. transport c. network d. data link e. physical 21. What type of network cable is used between a PC serial port and a console port? a. cross-over b. straight-through c. rollover d. patch cable 22. Which is an advantage of client/server networks? a. centralized security b. single point of failure c. lower operating costs d. users control their own resources 23. At which point do individuals connect directly to the ISP network to obtain Internet access? a. at a POP b. at an IXP c. at a Metro Ethernet link d. on the ISP extranet 24. The IT manager of a medium-sized business wishes to house the company-owned web servers in a facility that offers round-theclock controlled access, redundant power, and high-bandwidth Internet access. Which ISP service will fulfill this need? a. web hosting b. planning and provisioning c. application hosting d. equipment collocation 25. What support service team is commonly found within an ISP? a. help desk b. computer support c. application readiness d. implementation and documentation 26. Which network utility helps determine the location of network problems and identifies routers that packets travel across? a. ping b. ipconfig c. tracert d. nslookup 27. What is the first step that is used by a help desk technician in a systematic approach to helping a customer solve a problem? a. identify and prioritize alternative solutions b. isolate the cause of the problem c. define the problem d. select an evaluation process 28. Which items are typically found in an MDF? a. user workstations b. switches and routers c. fax machines d. copiers Σελίδα 3 από 7

4 29. The DHCP server in a lab is down when multiple DHCP clients in the lab are booted. How will the DHCP clients be affected? a. The clients will not boot completely until the DHCP server resumes functioning. b. A link-local address will be automatically assigned by the operating system. c. A link-local process will use a DNS query to determine if any other device uses the same link-local address. 30. Which address is used by the router to direct a packet between networks? a. source MAC address b. destination MAC address c. source IP address d. destination IP address 31. Which device has the ability to break up broadcast and collision domains? a. repeater b. hub c. router d. switch 32. Only one workstation on a particular network cannot reach the Internet. What is the first troubleshooting step if the divideand-conquer method is being used? a. Check the NIC, then check the cabling. b. Check the workstation TCP/IP configuration. c. Test all cables, and then test layer by layer up the OSI model. d. Attempt to Telnet, and then test layer by layer down the OSI model. 33. Complete the sentence: WEP is used to, and EAP is used to wireless networks. a. encrypt; authenticate users on b. filter traffic; select the operating frequency for c. identify the wireless network; compress data on d. create the smallest wireless network; limit the number of users on 34. Which is a physical-layer network problem? a. software configuration b. devices not able to ping c. loose cable connections d. device driver configuration 35. What command can give the location of delay for a packet traversing the Internet? a. netstat b. nslookup c. ping d. tracert 36. Which factor affects the number of access points needed for a wireless network? a. the number of interior walls b. the encryption method used on the wireless network c. the use of both Windows and Apple operating systems d. the use of infrared on the AP 37. What is a widely distributed approach to marketing on the Internet that advertises to as many users as possible via ? a. brute force b. spam c. spyware d. tracking cookies 38. What is one of the purposes of NAT? a. filters network traffic based on IP addresses b. prevents external users from detecting the IP addresses used on a network c. inspects traffic that might be harmful or used in an attack against the network d. translates IP addresses into easy-toremember domain names 39. Which term is used to describe the process of placing one message format into another format so that the message can be delivered across the appropriate medium? a. flow control b. encapsulation c. encoding d. multicasting Σελίδα 4 από 7

5 40. Whenever clients send messages, what device is used to translate the domain names into their associated IP addresses? a. Uniform Resource Locator b. Network redirector server c. SNMP server d. DNS server 41. A device receives an Ethernet frame and recognizes the MAC address as its own. What does the device do to get the data? a. removes the IP header b. removes the TCP header c. passes data to the application layer d. removes Ethernet header and trailer 42. Which is contained in an Ethernet header? a. source IP address b. source MAC address c. destination IP address d. destination port address 43. A host with IP address and a default mask belongs to what network? a b c d Which default subnet mask provides the most host bits? a b c d Which type of server dynamically assigns an IP address to a host? a. ARP b. DHCP c. DNS d. RARP 47. Which device can act as a router, switch, and wireless access point in one package? a. hub b. bridge c. modem d. repeater e. ISR 48. What is a major characteristic of asymmetric Internet service? a. Download and upload speeds are equal. b. Download speeds are lower than upload speeds. c. Upload speeds and download speeds are different. d. Upload speeds and download speeds are irrelevant. 49. A switch receives a frame with a destination MAC address that is not in the MAC table. What does the switch do? a. It drops the frame. b. It sends out an ARP request looking for the MAC address. c. It floods the frame out of all active ports, except the origination port. d. It returns the frame to the sender. 50. If the default gateway is configured incorrectly on a host, what is the problem? a. The host is unable to communicate on the local network. b. The host can communicate with other hosts on the local network, but cannot communicate with hosts on remote networks. c. The host can communicate with hosts on remote networks, but cannot communicate with hosts on the local network. d. There is no impact on communications. 46. Which is a network layer protocol? a. IP b. UDP c. TCP d. HTTP Σελίδα 5 από 7

6 ΜΕΡΟΣ Β : Να λύσετε όλες τις ασκήσεις. Κάθε άσκηση βαθμολογείται με τις μονάδες που φαίνονται στα δεξιά. 1. Καταγράψετε με τη σωστή σειρά τα επίπεδα (layers) του μοντέλου OSI. [7] Από ποιο επίπεδο του μοντέλου OSI θα αρχίζαμε το troubleshooting με τη μεθοδολογία divide-and-conquer; [3] Ποιες δύο εντολές θα δώσετε για το σκοπό αυτό; [4] 3. Περιγράψετε δύο υπηρεσίες που προσφέρει ένας παροχέας υπηρεσιών διαδικτύου (ISP). [10] (α)... (β) Αναφορικά με το πρωτόκολλο ARP (Address Resolution Protocol): (α) Εξηγήστε το σκοπό του. [4] (β) Εξηγείστε τον τρόπο λειτουργίας του, κάνοντας αναφορά στη δημιουργία των Ethernet Frames όταν πρόκειται να στείλουμε ένα πακέτο από ένα host σε άλλο, στο ίδιο τοπικό δίκτυο. [5] Σελίδα 6 από 7

7 5. Περιγράψετε δύο πλεονεκτήματα και δύο μειονεκτήματα των ασύρματων τοπικών δικτύων σε σύγκριση με τα ενσύρματα τοπικά δίκτυα. [8] Πλεονέκτημα (α) Πλεονέκτημα (β) Μειονέκτημα (α) Μειονέκτημα (β) 6. Εξηγείστε το ρόλο του switch σε ένα τοπικό δίκτυο, κάνοντας σύγκριση με το hub. [9] Τέλος Δοκιμίου Οι εισηγητές: Αλέξανδρος Παπαλυσάνδρου, Β.Δ.Α Δρ Αναστάσιος Φαλάς, Β.Δ. Συντονιστής Β.Δ. Δρ Αναστάσιος Φαλάς, Β.Δ. Ο Διευθυντής Ανδρέας Φιλίππου Σελίδα 7 από 7