ActualTests.Cisco.640-802.Exam.Q.and.A.08.15.08-DDU (1130589), страница 14
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ACLFour router functions in your network can be listed as follows:* Packet switching* Packet filtering* Internetwork communication* Path selectionQUESTION 115:Which of the following devices can the Certkiller network administrator use tosegment the LAN? (Choose all that apply)A. HubsB. RepeatersC. SwitchesD. BridgesE.
RoutersF. Media ConvertersActualtests.com - The Power of Knowing640-802G. All of the aboveAnswer: C, D, EExplanation:Switches and bridges forward broadcast but routers do not forward broadcasts by default(they can via the "ip helper-address" command).Switches, bridges and routers can segment an Ethernet collision domain via the use ofVLAN'sIncorrect Answers:A. Hubs is incorrect because a hub doesn't segment a network, it only allows more hostson one. Hubs operate at layer one, and is used primarily to physically add more stationsto the LAN.B.
This also incorrect because the job of a repeater is to repeat a signal so it can exceeddistance limitations. It also operates at layer one and provides no means for logical LANsegmentation.F. This is incorrect because media converters work by converting data from a differentmedia type to work with the media of a LAN. It also operates at layer one and providesno means for logical LAN segmentation.QUESTION 116:Within the Certkiller office, The Sales and Production networks are separated by arouter as shown in the diagram below:Which of the following statements most accurately describes the characteristics ofthe above networks broadcast and collision domains? (Select the two best answerchoices)A.
There are two broadcast domains in the network.B. There are four broadcast domains in the network.C. There are six broadcast domains in the network.Actualtests.com - The Power of Knowing640-802D. There are four collision domains in the network.E. There are five collision domains in the network.F. There are seven collision domains in the network.Answer: A, FExplanation:In this network we have a hub being used in the Sales department, and a switch beingused in the Production department.
Based on this, we have two broadcast domains: onefor each network being separated by a router. For the collision domains, we have 5computers and one port for E1 so we have 6 collision domains total because we use aswitch in the Production Department so 5 are created there, plus one collision domain forthe entire Sales department because a hub is being used.QUESTION 117:The Certkiller corporate LAN consists of one large flat network. You decide tosegment this LAN into two separate networks with a router. What will be the affectof this change?A. The number of broadcast domains will be decreased.B.
It will make the broadcasting of traffic between domains more efficient betweensegments.C. It will increase the number of collisions.D. It will prevent segment 1's broadcasts from getting to segment 2.E. It will connect segment 1's broadcasts to segment 2.Answer: DExplanationA router does not forward broadcast traffic. It therefore breaks up a broadcast domain,reducing unnecessary network traffic. Broadcasts from one segment will not be seen onthe other segment.Incorrect Answers:A.
This will actually increase the number of broadcast domains from one to two.B. All link level traffic from segment one to segment two will now need to be routedbetween the two interfaces of the router. Although this will reduce the traffic on the LANlinks, it does also provide a less efficient transport between the segments.C. Since the network size is effectively cut into half, the number of collisions shoulddecrease dramatically.E. Broadcasts from one segment will be completely hidden from the other segment.QUESTION 118:Actualtests.com - The Power of Knowing640-802You want to influence the root bridge selection within the Certkiller LAN. Whichtwo values are used by spanning tree protocol to elect a root bridge? (Choose two.)A.
Amount of RAMB. Speed of the linksC. IOS VersionD. MAC AddressE. Bridge PriorityF. IP AddressG. Router IDAnswer: D, EExplanation:Switch having lowest bridge ID will become the root bridge. The bridge ID is how STPkeeps track of all the switches in the network. It is determined by a combination of thebridge priority (32,768 by default on all Cisco switches) and the base MAC address. Thebridge with the lowest bridge ID becomes the root bridge in the network.QUESTION 119:A Certkiller Ethernet switch receives a unicast frame with a destination MAC thatIS listed in the switch table.
What will this switch do with the frame?A. The switch will forward the frame to a specific portB. The switch will forward the frame to all ports except the port on which it was receivedC. The switch will return a copy of the frame out the source portD. The switch will not forward unicast framesE.
The switch will remove the destination MAC from the switch tableF. None of the above.Answer: AExplanation:How Does the Switch Find Host MACs?Let's use the diagram below to help us understand how address learning process takesplace.Actualtests.com - The Power of Knowing640-802Let's assume that we have just powered on the switch. It has nothing in its MAC table.We connect the cables from the hosts on the switch interfaces as shown in the diagram.Host A initiates a connection towards Host D, and the following takes place:1. Host A (interface fe0/0) sends a frame to Host D (MAC address:0000.43c5.334c).2.
The switch inspects the Source Address in the frame and notes in its table the MACaddress of Host A along with the Interface number from which the frame originated.3.The switch inspects the Destination Address in the frame. Since it does not have Hosts DMAC address in its table, it constructs a broadcast frame and forwards out all interfacesexcept the interface from where the original frame arrived.4. Host D identifies itself as the expected recipient and responds back to HostA. Theswitch receives the respond frame on interface fe0/11 and places the SA in its table alongwith the interface number where the frame came from.5.
From now on, further communication between the two hosts will be switched tothe appropriate interfaces based on the MAC tables entries.This process takes place every time a new host is attached on the switch and initiatestraffic. The switch tries to keep its MAC table up-to-date, therefore if some hosts do notinitiate traffic for a certain amount of time, the switch removes them from its table andreinserts them when they begin sending traffic.Reference:http://www.trainsignaltraining.com/studying-for-your-ccent-learn-all-about-switching-and-stp/2007-11-01/QUESTION 120:Actualtests.com - The Power of Knowing640-802In which circumstance are multiple copies of the same unicast frame likely to betransmitted in the Certkiller Switched LAN?A.
During high traffic periodsB. In an improperly implemented redundant topologyC. After broken links are re-establishedD. When upper-layer protocols require high reliabilityE. When a dual ring topology is in useF. None of the aboveAnswer: BExplanation:A redundant topology eliminates single points of failure, but it also causes broadcaststorms, multiple frame copies, and MAC address table instability problems. MultipleFrame Copies--when a new switch is added, the other switches may not have learned itscorrect MAC address.
The host may send a unicast frame to the new switch. The frame issent through several paths at the same time. The new switch will receive several copies ofthe frame. This causes MAC database instability. MAC database instability results whenmultiple copies of a frame arrive on different ports of a switch. Layer 2 has nomechanism to stop the loop.
This is the main reason for the Spanning Tree Protocol(STP)IEEE 802.1d which was developed to prevent routing loops.If multiple connections between switches are created for redundancy purposes, networkloops can occur in an improperly designed topology. Spanning Tree Protocol (STP) isused to stop network loops while still permitting redundancy.QUESTION 121:Part of the Certkiller switched LAN is shown below:Based on the information show above, which device will provide the spanning-treeActualtests.com - The Power of Knowing640-802designated port role for the Certkiller network segment that services the printers?A. Switch Certkiller AB. Hub Certkiller EC. Switch Certkiller CD. Switch Certkiller BE. Switch Certkiller DF. None of the switches will provide the designated port roleAnswer: CExplanation:Designated port A designated port is one that has been determined as having the best(lowest) cost.
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