CCNA系列认证CCNA(640-801)章节练习(2019.05.07)

单项选择题
The Testking network is implementing dialup services for their remote employees.Testking uses several different Layer 3 protocols on the network. Authentication ofthe users connecting to the network is required for security. Additionally, some employees will be dialing long distance and will need callback support.Which protocol is the best choice for these remote access services?（）
A.802.1
B.Framerelay
C.HDLC
D.PPP
E.SLIP
F.PAP
多项选择题
The TestKing network Topology is displayed in the exhibit belowA switch has been configured for three different VLANs: VLAN 2, VLAN 3, andVLAN 4. For the purposes of communication between VLANs a router is to beadded. Host from one VLAN should be able to reach the hosts in the other VLANs.Based on this requirement, what type of connection is acceptable between the routerand switch?（）
A. 10 Mbps Ethernet
B. 56 kbps serial
C. 100 Mbps Ethernet
D. 1,544 Mbps serial
E. 1000 Mbps Ethernet
多项选择题
What are some of the characteristics of the OSPF routing protocol?（）
A. It confines network instability to a single area of network.
B. It increases the routing overhead of the network
C. It supports VLSM
D. It routes between Autonomous Systems.
E. It allows extensive control of routing updates
F. None of the above
多项选择题
Which of the following are VLAN frame encapsulation types that may be configured on a Catalyst switch?（）
A. VTP
B. ISL
C. CDP
D. 802.1Q
E. 802.1p
F. LLC
单项选择题
By default, which of the following factors determines the spanning-tree path cost?（）
A. It is the individual link cost based on latency
B. It is the sum of the costs based on bandwidth
C. It is the total hop count
D. It is dynamically determined based on load
单项选择题
You have a single Class C IP address and a point-to-point serial link that you want to implement VLSM on. Which subnet mask is the most efficient?（）
A. 255.255.255.0
B. 255.255.255.240
C. 255.255.255.248
D. 255.255.255.252
E. 255.255.255.254
单项选择题
Which is the correct fallback sequence for loading the Cisco IOS?（）
A. ROM, Flash, NVRAM
B. ROM, TFTP server, Flash
C. Flash, TFTP server, ROM
D. Flash, NVRAM, RAM
多项选择题
What should be done prior to backing up an IOS image to a TFTP server?（）
A. Make sure that the server can be reached across the network.
B. Check the authentication for TFTP access to the server is set.
C. Assure that the network server as adequate space for the IOS image.
D. Verify file naming and path requirements.
E. Make sure that the server can store binary files.
F. Adjust the TCP window size to speed up the transfer.
单项选择题
Which one of the following statements best explains the split horizon rule used in distance vector routing protocols?（）
A. Only routers can split boundaries (horizons) between concentric networks.
B. Each AS must keep routing tables converged to prevent dead routes from being advertised across boundaries.
C. Networks can only remain fully converged if all information is sent out all active interfaces.
D. Information about a route should not be sent back in the direction from which the original update came.
E. Distance vector protocols need fall back routers that are responsible for momentary loops.
多项选择题
Regarding PAR (Positive Acknowledgement and Re-transmission), which of the answer choices below are correct?（）
A. The source device will only retransmit lost packets on the request of the destination device.
B. The source device starts a timer when it sends a segment and retransmits if an acknowledgment is not received before the timer expires.
C. The destination device acknowledges receipt of a segment by sending a packet with a new sequence number and the ACK bit sent.
D. The destination device acknowledges receipt of a segment by sending a packet that indicates the next sequence number it expects.
E. If the destination device does not receive a segment, all segments are retransmitted.
F. The source device keeps a record of all segments sent and expects and acknowledgment of each.