[CCNA] [200-120] 스위치 (8/63)

지난강좌 : [CCNA][200-120] HSRP, VRRP 그리고 GLBP (1/36)

지난강좌 : [CCNA][200-120] SNMP (2/36)

지난강좌 : [CCNA][200-120] NetFlow (3/36)

지난강좌 : [CCNA][200-120] Syslog(4/36)

지난강좌 : [CCNA][200-120] OSI 7 레이어 & TCP/IP 레이어 (5/36)

지난강좌 : [CCNA][200-120] 시스코 IOS (6/36)

지난강좌 : [CCNA][200-120] WAN (7/36)

Q1) Refer to the exhibit
Switch-1# show mac address-table
Dynamic Address Count: 3
Secure Addressses (User-defined) Count: 0
Static Addresses (User-defined) Count: 0
System Self Addresses Count: 41
Total Mac Addresses: 50
Non-static Address Table:
Destination Address Address Typ VLAN Destination Port
001.0de0.e289 Dynamic 1 FastEthernet0/1
0010.7b00.1540 Dynamic 2 FastEthernet0/3
0010.7b00.1545 Dynamic 2 FastEthernet0/2
Switch-1 needs to send data to a host with a MAC address of 00b0.d056.efa4. What will Switch-1 do with this data?

A. Switch-1 will drop the data because it does not have an entry for that MAC address.
B. Switch-1 will forward the data to its default gateway.
C. Switch-1 will flood the data out all of its ports except the port from which the data originated.
D. Switch-1 will send an ARP request out all its ports except the port from which the data originated.

해설) 스위치가 찾는 맥어드레스가 없는 관계로 모든 스위치 포트에 해당 맥어드레스를 브로드캐스트 할 것이다. 그러므로 답은 C이다.

Q2) A switch is configured with all ports assigned to vlan 2 with full duplex FastEthernet to segment existing departmental traffic. What is the effect of adding switch ports to a new VLAN on the switch?

A. More collision domains will be created.
B. IP address utilization will be more efficient.
C. More bandwidth will be required than was needed previously.
D. An additional broadcast domain will be created.

해설) 새로운 vlan을 생성함으로 해서 브로드캐스트 도메인을 생성할 수 있게 된다. vlan이 레이어2에서 레이어3와 같이 네트워크를 나누어 주는 역할을 하므로 해당 vlan내에서 브로드캐스팅이 되게 된다. 추가로 collision domain은 스위치를 사용함으로써 호스트간의 충돌을 막을 수 있다.

Q3) The two connected ports on the switch are not turning orange or green. What would be the most effective steps to troubleshoot this physical layer problem? (Choose three)

A. Ensure that the Ethernet encapsulations match on the interconnected router and switch ports.
B. Ensure that cables A and B are straight-through cables.
C. Ensure cable A is plugged into a trunk port.
D. Ensure the switch has power.
E. Reboot all of the devices.
F. Reseat all cables.

해설) 불이 안들어 온다는 것은 물리적인 문제가 있다는 것으로 보고 물리적인 확인만 하면 되므로 B, D, F가 답이다.

Q4) 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 collision domains would remain the same.
B. The number of collision domains would decrease.
C. The number of collision domains would increase.
D. The number of broadcast domains would remain the same.
E. The number of broadcast domains would decrease.
F. The number of broadcast domains would increase.

해설) 스위치로 장치를 바꿈으로써 각각의 호스트가 하나의 collion도메인이 되므로 collion 도메인은 늘어날 것이고 브로드캐스트 도메인은 vlan이나 아이피를 바꾸지 않는 이상 변하지 않는다. 그래서 답은 C,D이다.

Q5) Give this output for SwitchC, what should the network administrator’s next action be?
741 input errors, 739 CRC
A. Check the trunk encapsulation mode for SwitchC’s fa0/1 port.
B. Check the duplex mode for SwitchC’s fa0/1 port.
C. Check the duplex mode for SwitchA’s fa0/2 port.
D. Check the trunk encapsulation mode for SwitchA’s fa0/2 port.

해설) CRC는 Cycle Redundancy Check의 약자로 raw 데이타의 오류를 나타내는 값으로 보통 듀플렉스 모드가 맞지 않는 경우에 많이 발생한다. 해당 문제의 그림은 없지만 CRC에러는 fa0/1에서 발생했으며 상대방 스위치인 SwitchA의 fa0/2를 확인해야 한다. 그러므로 답은 C이다.

Q6) Which three statements accurately describe layer 2 Ethernet switches? (choose three)

A. Microsegmentation decreases the number of collisions on the network.
B. If a switch receives a frame for an unknown destination.it uses ARP to resolve the address.
C. Spanning Tree Protocol allows switches to automatically share vlan information.
D. In a properly functioning network with redundant switched paths, each switched segment will contain one root bridge with all its ports in the forwarding state. All other switches in that broadcast domain will have only one root port.
E. Establishing vlans increases the number of broadcast domains.
F. Switches that are configured with vlans make forwarding decisions based on both layer 2 and layer 3 address information.

해설) 세그먼트를 나눔으로써 (Microsegmentation) 패킷간 충돌을 피하게 된다. 그리고 한 네트워크에서 root port는 하나만 존재하고, vlan을 생성함으로 브로드캐스트 도메인이 생성되게 된다. 그러므로 답은 A, D, E이다.

Q7) Why will a switch never learn a broadcast address?

A. Broadcast frames are never sent to switches.
B. Broadcast addresses use an incorrect format for the switching table.
C. A broadcast address will never be the source address of a frame.
D. Broadcasts only use network layer addressing.
E. A broadcast frame is never forwarded by a switch.

해설) 브로드케스트 주소는 소스어드레스를 포함하지 않으므로 답은 C이다.