640-802 Cisco Certified Network Associate (CCNA)

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Question 1

Which of the following are true regarding bridges and switches? (Choose two.)

  • A. Bridges are faster than switches because they have fewer ports.
  • B. A switch is a multiport bridge.
  • C. Bridges and switches learn MAC addresses by examining the source MAC address of each frame received.
  • D. A bridge will forward a broadcast but a switch will not.
  • E. Bridges and switches increase the size of a collision domain.


Answer : B,C

Explanation: Bridge is a Layer2 device, which is designed to create two or more LAN segments. Each segment is an independent collision domain. Bridge is also created to provide more available bandwidth, Its purpose is to filter the LAN traffic, making local traffic be in the local area, and those directed to other parts of the LAN (sub) be forwarded there. Each NIC on each device has a unique MAC address. Bridge will record the MAC address of each port and then make forwarding decisions based on this MAC address table. Switch is a device of the data link layer, it combines multiple physical LAN segments into a large network.. Similar to bridge, the switch will transfer and flood the communication frames based on the MAC address. Because the switching process is performed in hardware, the switching speed of the switch is faster than that of a bridge performed by software. Regarding each switching port as a mini-bridge, then each switching port will work as an independent bridge to provide full medium's bandwidth to each host.

Question 2

Refer to the exhibit.


HostA cannot ping HostB. Assuming routing is properly configured, what could be the
cause of this problem?

  • A. HostA is not on the same subnet as its default gateway.
  • B. The address of SwitchA is a subnet address.
  • C. The Fa0/0 interface on RouterA is on a subnet that can’t be used.
  • D. The serial interfaces of the routers are not on the same subnet.
  • E. The Fa0/0 interface on RouterB is using a broadcast address.


Answer : D

Explanation: Explanation Now lets find out the range of the networks on serial link: For the network 192.168.1.62/27: Increment: 32Network address: 192.168.1.32Broadcast address: 192.168.1.63 For the network 192.168.1.65/27: Increment: 32Network address: 192.168.1.64Broadcast address: 192.168.1.95 -> These two IP addresses dont belong to the same network and they cant see each other -> D is the correct answer.

Question 3

Refer to the diagram. Which three statements describe the router port configuration and the
switch port configuration as shown in the topology? (Choose three.)


  • A. The Router1 WAN port is configured as a trunking port.
  • B. The Router1 port connected to Switch1 is configured using subinterfaces.
  • C. The Router1 port connected to Switch1 is configured as 10 Mbps.
  • D. The Switch1 port connected to Router1 is configured as a trunking port.
  • E. The Switch1 port connected to Host B is configured as an access port.
  • F. The Switch1 port connected to Hub1 is configured as full duplex.


Answer : B,D,E

Explanation: There are two types of links in switched network: Access link or access port belongs to a single VLAN and frames will be forwarded only to this VLAN. Access link often provides connection between switches, between switches and PCs or other devices. In the above figure, the port connecting Switch1to Host B should be configured as access port. Trunk link or trunk port is by default a member of all the VLANs that exist on the switch and carry traffic for all those VLANs between the switches, between switches and routers or specific servers. In this question, the port connecting Switch1 to Router1 should be configured as the trunk port. The main difference between trunk link and access link is that switch will send some VLAN information out through trunk link instead of access link.

Question 4




Answer :

Question 5

: 33
Which two statements describe the advantages to the use of RIP over the use of OSPF?
(Choose two.)

  • A. RIP requires less time to converge.
  • B. RIP is less complex to configure.
  • C. RIP uses less bandwidth.
  • D. RIP has a more accurate metric.
  • E. RIP demands fewer router resources.


Answer : B,E

Question 6

How is an EUI-64 format interface ID created from a 48-bit MAC address?

  • A. by appending 0xFF to the MAC address
  • B. by prefixing the MAC address with 0xFFEE
  • C. by prefixing the MAC address with 0xFF and appending 0xFF to it
  • D. by inserting 0xFFFE between the upper three bytes and the lower three bytes of the MAC address
  • E. by prefixing the MAC address with 0xF and inserting 0xFafter each of its first three bytes


Answer : D

Question 7

Given that Host A and Host B are in different networks. When Host A is trying to
communicate with Host B, which step will Host A take first?

  • A. Send a TCP SYN and wait for the SYN ACK with the IP address of Host B.
  • B. Drop the data.
  • C. Create an ARP request to get a MAC address for Host B.
  • D. Send the data frames to the default gateway.


Answer : D

Explanation: The answer Create an ARP request to get a MAC address for Host B. is NOT correct, the host will know if the destination is not on the local network and will send to MAC address of its default gateway setting, it will not ARP for MAC address of remote destination.

Question 8

Refer to the exhibit.


Which two devices can be used to complete the connection between the WAN router at the
customer site and the service provider? (Choose two.)

  • A. modem
  • B. ISDN TA
  • C. CSU/DSU
  • D. ATM switch
  • E. Frame Relay switch
  • F. WAN switch


Answer : A,C

Question 9

Refer to the exhibit. What two results would occur if the hub were to be replaced with a
switch that is configured with one Ethernet VLAN? (Choose two.)


  • A. The number of broadcast domains would remain the same.
  • B. The number of collision domains would increase.
  • C. The number of collision domains would decrease.
  • D. The number of broadcast domains would decrease.
  • E. The number of collision domains would remain the same.
  • F. The number of broadcast domains would increase.


Answer : A,B

Explanation: Basically, a collision domain is a network segment that allows normal network traffic to flow back and forth. In the old days of hubs, this meant you had a lot of collisions, and the old CSMA/CD would be working overtime to try to get those packets re-sent every time there was a collision on the wire (since ethernet allows only one host to be transmitting at once without there being a traffic jam). With switches, you break up collision domains by switching packets bound for other collision domains. These days, since we mostly use switches to connect computers to the network, you generally have one collision domain to a PC. Broadcast domains are exactly what they imply: they are network segments that allow broadcasts to be sent across them. Since switches and bridges allow for broadcast traffic to go unswitched, broadcasts can traverse collision domains freely. Routers, however, don't allow broadcasts through by default, so when a broadcast hits a router (or the perimeter of a VLAN), it doesn't get forwarded. The simple way to look at it is this way: switches break up collision domains, while routers (and VLANs) break up collision domains and broadcast domains. Also, a broadcast domain can contain multiple collision domains, but a collision domain can never have more than one broadcast domain associated with it. Collision Domain: A group of Ethernet or Fast Ethernet devices in a CSMA/CD LAN that are connected by repeaters and compete for access on the network. Only one device in the collision domain may transmit at any one time, and the other devices in the domain listen to the network in order to avoid data collisions. A collision domain is sometimes referred to as an Ethernet segment. Broadcast Domain: Broadcasting sends a message to everyone on the local network (subnet). An example for Broadcasting would be DHCP Request from a Client PC. The Client is asking for a IP Address, but the client does not know how to reach the DHCP Server. So the client se

Question 10

: 36
Refer to the exhibit.


The network administrator requires easy configuration options and minimal routing protocol
traffic. What two options provide adequate routing table information for traffic that passes
between the two routers and satisfy the requests of the network administrator? (Choose
two)

  • A. a dynamic routing protocol on InternetRouter to advertise all routes to CentralRouter.
  • B. a dynamic routing protocol on InternetRouter to advertise summarized routes to CentralRouter.
  • C. a static route on InternetRouter to direct traffic that is destined for 172.16.0.0/16 to CentralRouter.
  • D. a dynamic routing protocol on CentralRouter to advertise all routes to InternetRouter.
  • E. a dynamic routing protocol on CentralRouter to advertise summarized routes to InternetRouter.
  • F. a static, default route on CentralRouter that directs traffic to InternetRouter.


Answer : C,F

Question 11

Refer to the exhibit. An administrator pings the default gateway at 10.10.10.1 and sees the
output as shown. At which OSI layer is the problem?


  • A. data link layer
  • B. application layer
  • C. access layer
  • D. session layer
  • E. network layer


Answer : E

Explanation: The command ping uses ICMP protocol, which is a network layer protocol used to propagate control message between host and router. The command ping is often used to verify the network connectivity, so it works at the network layer.

Question 12

Refer to the exhibit. What type of connection would be supported by the cable diagram
shown?


  • A. PC to router
  • B. PC to switch
  • C. server to switch
  • D. switch to router


Answer : A

Explanation: Explanation This is a crossover cable so it can be used to connect PC and router.

untitled

Question 13

Refer to the exhibit. The FMJ manufacturing company is concerned about unauthorized
access to the Payroll Server. The Accounting1, CEO, Mgr1, and Mgr2 workstations should
be the only computers with access to the Payroll Server. What two technologies should be
implemented to help prevent unauthorized access to the server? (Choose two.)


  • A. access lists
  • B. encrypted router passwords
  • C. STP
  • D. VLANs
  • E. VTP
  • F. wireless LANs


Answer : A,D

Explanation: Explanation Access lists and VLANs can be used to prevent unauthorized to the Payroll Server. By assigning the server to a secure VLAN and using access list to permit only Accounting1, CEO, Mgr1, and Mgr2 workstations to access that VLAN, we can dramatically enhance the security of the whole network. We dont need to encrypt router password because it only helps prevent unauthorized access to the router, not Payroll server -> B is not totally correct ^^.

Question 14

: 43
A receiving host computes the checksum on a frame and determines that the frame is
damaged. The frame is then discarded. At which OSI layer did this happen?

  • A. physical
  • B. session
  • C. data link
  • D. transport
  • E. network


Answer : C

Explanation: The Data Link layer provides the physical transmission of the data and handles error notification, network topology, and flow control. The Data Link layer formats the message into pieces, each called a data frame, and adds a customized header containing the hardware destination and source address. Protocols Data Unit (PDU) on Datalink layer is called frame. According to this question the frame is damaged and discarded which will happen at the Data Link layer.

Question 15

The corporate head office 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.


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.

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