CCNA QUESTIONS 1 TO 10 QUESTION 1: Which protocol below uses ...

CCNA QUESTIONS 1 TO 10 QUESTION 1: Which protocol below uses TCP port 443 at layer 4? A. HTML B. HTTPS C. TFTP D. Telnet E. SMTP F. None of the above Answer: B Explanation: A. HTML is not a protocol. C. TFTP uses UDP port 69. D. Telnet uses TCP port 23. E. SMTP uses TCP port 25.

QUESTION 2: Which of the following services use TCP? (Choose three) A. DHCP B. SMTP C. SNMP D. FTP E. HTTP F. TFTP Answer: B, D, E Explanation: TCP (Transmission Control Protocol) is a reliable mechanism for data delivery. SMTP, FTP and HTTP services use TCP via ports 25, 20/21, and 80, respectively.

QUESTION 3: Which of the following are types of flow control? (Choose three) A. Buffering B. Cut-through C. Windowing D. Congestion avoidance E. Load balancing Answer: A, C, D

Explanation: Data transmission flow control occurs at layer 4 with the help of buffering, windowing and congestion avoidance.

QUESTION 4: Ciscoland is installing IP phones in a new office. The phones and office computers connect to the same device. To ensure maximum throughout for the phone data sessions, the company needs to make sure that the phone traffic is on a different network from that of the office computer data traffic. What is the best network device to which to directly connect the phones and computers and what technology should be implemented on this device? (Choose two) A. Subinterface B. STP C. Hub D. Switch E. Router F. Wireless Access Point G. VLAN H. VTP Answer: D, G Explanation: IP Phones need to be connected to LAN Switches, which usually provide line power to them using PoE (Power over Ethernet) technology. According to best practice rules, a separate “Voice VLAN” should be created for the IP Phone network.

QUESTION 5: The Head Office of a Corporation has a teleconferencing system that uses VOIP (Voice over IP) technology. This system uses UDP as the transport for the data transmissions. If these UDP datagrams arrive at their destination out of sequence, what will happen? A. UDP will send an ICMP Information Request to the source host. B. UDP will pass the information in the datagrams up to the next OSI layer in the order that they arrive. C. UDP will drop the datagrams. D. UDP will use the sequence numbers in the datagram headers to reassemble the data in the correct order. E. UDP will not acknowledge the datagrams and wait for a retransmission of the datagrams. Answer: B

Explanation: VOIP systems utilize UDP because it is faster and uses less overhead. In addition, the reliable transport mechanism used in TCP is useless to VOIP because if a packet gets dropped and needs to be resent, it will be already too late. UDP provides a service for applications to exchange messages. Unlike TCP, UDP is connectionless and provides no reliability, no windowing, and no reordering of the received data. However, UDP provides some functions of TCP , such as data transfer, segmentation, and multiplexing using port numbers, and it does so with fewer bytes of overhead and with less processing required. UDP data transfer differs from TCP data transfer in that no reordering or recovery is accomplished. Applications that use UDP are tolerant of lost data, or they have some application mechanism to recover data loss. Reference: CCNA Self-Study CCNA INTRO exam certification Guide (Cisco Press, ISBN 1-58720-094-5) Page 161.

QUESTION 6: Which line from the output of the show ip interface command indicates that there is a Layer 1 problem? A. Serial0/1 is up, line protocol is down B. Serial0/1 is down, line protocol is down C. Serial0/1 is up, line protocol is up D. Serial0/1 is administratively down, line protocol is down E. None of the above Answer: B Explanation: When the physical interface itself is down, then the problem is related to layer 1. When it is up, but the line protocol is down, then the problem is related to layer 2. Reference: www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1915.html

QUESTION 7: At which layer of the OSI model does the protocol that provides the information displayed by the "show cdp neighbors" command operate? A. Transport B. Physical C. Application D. Data link E. Network Answer: D

Explanation: CDP is a device discovery protocol that runs over Layer 2 (the data link layer) on all Cisco-manufactured devices (routers, bridges, access servers, and switches) and allows network management applications to discover Cisco devices that are neighbors of already known devices. With CDP, network management applications can learn the device type and the Simple Network Management Protocol (SNMP) agent address of neighboring devices running lower-layer, transparent protocols.

QUESTION 8: Which three of the protocols below belong to the application layer? (Select three answer choices) A. ARP B. HTTPS C. SMTP D. CDP E. TFTP F. ICMP Answer: B, C, E Explanation: The application layer is the highest OSI layer, and protocols at this layer are end-user oriented. HTTPS so people can get information on the internet, SMTP so people can manage networks, and TFTP so people can download files. Incorrect Answers: A, D, F. ARP, CDP, ICMP are protocols that equipment like routers and switches use to communicate with themselves, and belong to lower levels on the model.

QUESTION 9: Split horizon has been enabled within a routed network. Which one of the following statements best explains the split horizon rule? A. Only routers can split boundaries (horizons) between networks in separate AS numbers. B. Each AS must keep routing tables converged to prevent dead routes from being advertised across boundaries. C. Once a route is received on an interface, advertise that route as unreachable back out the same interface. D. Information about a route should never be sent back in the direction from which the original update came. E. None of the above Answer: D

Explanation: The split horizon rule states: Never advertise a route out of the interface through which you learned it. For instance, in Figure 4a below, if Router One is connected to Routers Two and Three through a single multipoint interface (such as Frame Relay), and Router One learned about Network A from Router Two, it will not advertise the route to Network A back out the same interface to Router Three. Router one assumes that Router Three would learn about Network A directly from Router Two. Incorrect Answers: A: There is no such requirement B: Distance vector protocols updates routing table at regular intervals instead of Topology changes C: This is the definition of the poison reverse rule, not the split horizon rule.

QUESTION 10: Which of the following commands would be applied to a WAN interface, but not on LAN Interface? (Choose all that apply) A. IP address B. encapsulation PPP C. no shutdown D. authentication CHAP E. Speed F. None of the above Answer: B, D Explanation: PPP encapsulation can be used in ISDN interfaces, Asynchronous serial interfaces, and point to point serial WAN connections. PPP is not an option for LAN interfaces. CHAP authentication is a PPP 3 way authentication method. CHAP authentication can only be used on PPP encapsulated interfaces and is not a LAN interface configuration option. Incorrect Answers: A, C. This command can be applied to both LAN and WAN interface types. E. The speed command is used on LAN interfaces, and is not used on WAN interface types.