Cùng nhau làm test !!!

[Hajime]

1 )Which devices can be connected to a VLAN trunk? (Choose three)
A.a switch
B.a hub
C.a router
D.a server with a special NIC
E.a CSU/DSU
F.a repeater

2) A network administrator is attemping to configure routing between VLANs over a trunked link. A trunk link cannot be established between a switch and a router. Which of the following are possible sources of this problem ?( choose two )

A. The router IOS does not support trunking
B. The port is connected and is not receiving alignment and FCS errors.
C. The switch duplex and speed does not set properly.
D. The router and switch are running different version of STP.
E. The switch IP address incorrectly configured.

3) Which of the following statements are true regarding a rootbridge in a spanning tree topology? ( choose two )

A. The root bridge timers control BPDU traffic on network
B. Only the show commands on the switch can display root bridge information
C. It is the central point of a spanning tree topology
D. Storm control is enabled by default.
E. VLANs cannot be trunked between switches until the root bridge has been elected.

4) How does a bridge handle a frames that it received? ( choose three)

A. if the source is unknown, the source port is shutdown.
B. if the source port of a frame is unknown, the bridge will issue an ARP request
C. if the destination is on another segment, the bridge will forward the frame only to the correct interface
D. A bridge will forward frames for unknown destinations to the default gateway.
E. if the destination port is unknown, a bridge will flood the frame to all ports in the broadcast domain, except for the source port
F. if the destination of the frame is on the same segment as the source, a bridge will not forward the frame.

5) What do the switch do when it receives a frame and the source address is unknown ?

A. The switch will discard the frame
B. The switch will request the sender resend the frame.
C. The switch will map the source address to the port on which it received.
D. The switch will flood the frame to all attached devices.
E. The switch will issue an ARP request to confirm that the source exit.

6) Which approach to assigning VLAN membership maximizes forwarding performance?

A. membership by MAC address
B. membership by logical address
C. membership by protocol
D. membership by port
E. membership by operating system.

Thân chào!!!
PS: Các bạn khi chọn câu trả lời, nhớ giải thích ( ngắn gọn ) tại sao mình chọn nhé.. đừng trả lời chung chung tớ chọn... vì tớ nghĩ vậy hay tớ nghĩ nó đúng ... Chúc vui:)

[VoThanhDuy]

Chào

Các thiết bị có thể làm trunking là routers, switch và một server có gắn card mạng đặc biệt hỗ trợ trunking (dot1q). Các card mạng loại xịn của Intel/HP thường có hỗ trợ trunking như vậy.

Để một routers và switch có thể thực hiện trunking, cần có IOS phù hợp thì mới có thể trunking được. Cụ thể là dot1q chỉ có thể thực hiện trên các phiên bản IOS PLUS. Bên cạnh đó, phần duplex và speed mismatch giữa routers và switch cũng rất quan trọng. Nếu cấu hình không tương thích, bạn có thể bị vấn đề duplex mismatch.

trong spanning tree, root bridge luôn là tâm điểm của mạng. Các thông số timers của root bridge ảnh hưởng lên toàn bộ các switch khác.

Để chia VLAN, bạn có thể dùng cách chia theo port hoặc theo MAC. Cách chia theo port sẽ làm tăng tốc độ switch frame.

Nếu một switch nhận một frame và địa chỉ source của frame này chưa biết, switch sẽ cập nhật địa chỉ source MAC vào port tương ứng trên switch.

Ngoài ra, câu số 4 là một câu hỏi khó nên mình không có ý kiến.

[kokichi81]

Câu 1:Cho mình hỏi thiết bị CSU/DSU khác thiết bị NTU ở chỗ nào.
Vì mình từng thấy hai switch nối đường trunk với nhau qua NTU.
Câu 4:
-Nếu bridge nhận được một gói tin ở khác segment,nó sẽ gửi gói tin đó ra port tương thích với segment đó.
-Nếu nó không tìm được port tương thích , nó sẽ gửi ra tất cả các port ngoại trừ port mà nó nhận gói tin.
-Trong trường hợp đích của gói tin là cung segment với source thì nó sẽ không forward gói tin đi.Nó se loại bỏ gói tin đó đi.

[cuongtran]

Nào mời các bạn cùng nhau chung sức tiếp tục tham gia các câu hỏi, các bạn chỉ cần chọn câu đúng là A hoặc B hoặc A và C..., cảm ơn các bạn

1. Which strategies can a company take to enhance network reliability through redundancy? (Choose two.)
Eliminate single points of failure.
A. Flood frames for unknown destinations.
B. Send multiple frames to an end device.
C. Design alternate routes to a destination.
D. Forward MAC address tables to all switches on the network.
E. Eliminate multiple paths to the same destination.

2. The network 192.1.1.0 has been subnetted for a network design. The 192.1.1.16/28 subnet has been chosen for further subnetting to provide for point-to-point serial link addressing. How many serial link subnets can be created while minimizing the number of wasted addresses?

A. 1
B. 2
C. 4
D. 6
E. 8
F. 16

3. Using Telnet, a network administrator is unable to log in to a switch located at another office in order to make configuration changes to it. What could be the problem?
A. The managmement station does not have access to a full-duplex Fast Ethernet link on the switch.
B. VLAN 1 on the switch is not configured for TCP/IP network access.
C. The switch must be managed from the local LAN.
D. The switch hostname has not been set.

4. What is the term that describes the cabling between the MDF and IDF locations as shown in the graphic?

A. horizontal cross-connect
B. horizontal cross-cabling
C. vertical cross-connect
D. vertical cross-cabling

5. A switched Ethernet network is experiencing unusually heavy traffic to the extent that network delays have become intolerable. While investigating the problem, a network administrator disconnects a redundant uplink between two switches. The excessive traffic quickly subsides. What was the likely cause of this problem?

A. broadcast storms
B. routing loops
C. multiple frame copies
D. load balancing
E. unicast frame forwarding


6. What is required for OSPF routers to share routing information?
A. designated routers
B. a backup designated router
C. neighbor adjacencies
D. an NBMA network topology
E. links configured on the 224.0.0.0 network

7. Under which of the following circumstances might two routers have trouble establishing a neighbor relationship in an OSPF network? (Choose three.)
A. Hello packets are not sent from either neighbor.
B. The interfaces are on different network types.
C. The network command has put the connected interfaces into the same OSPF area.
D. Slow network connections cause OSPF advertisements to time out.
Authentication passwords or keys are different.

8. What is indicated when an EIGRP route is in the passive state?

A. The route has the highest path cost of all routes to that destination network.
B. The route must be confirmed by neighboring routers before it is put in the active state.
C. The route is a feasible successor and will be used if the active route fails.
D. There is no activity on the route to that network.
E. The route is viable and can be used to forward traffic.


9. Which of the following tasks must be completed to configure a router interface to serve the newly added network 192.168.10.64/27 and to advertise this network over RIP v2? (Choose three.)
A. Configure RIP v2 with the network command and the IP network number for the new network.
B. Configure RIP v2 with the network command and the IP host address and subnet mask for the newly activated interface.
C. Configure the router with the ip subnet-zero command so that this network can be added and advertised.
D. Apply a network host address and subnet mask to the newly activated interface.
E. Activate the routing protocol with the router rip version 2 command.
Configure RIP on the other routers in the enterprise with an entry for the newly added network.

10. What do switches configured with VLANs provide to an enterprise network? (Choose three.)
A. bridging between VLANs
B. security
C. broadcast control
D. physical grouping of users
E. logical grouping of users
F. enlargement of collison domains

11. How can MAC address table entries be removed from a switch? (Choose two.)
A. Power cycle the switch to clear all dynamically learned addresses.
The clear switching-tables command will remove statically configured entries.
B. The clear mac-address-table command will remove statically and dynamically configured table entries.
C. The erase flash command will clear all statically configured table entries.
D. Statically configured MAC addresses will automatically be removed from the address table 300 minutes after the last activity on a switch port.


12. What is the purpose of a default route?
A. A default route will cause packets addressed to unknown destination networks to be dropped.
B. A default route will cause packets addressed to unknown destination networks to be sent to a designated router interface.
C. A default route will cause packets addressed to known destinations to prefer a specified path to the destination network.
D. A default route will direct packets for all destination networks to a designated router and router interface.

13. How do EIGRP routers actively maintain neighbor relationships?
A. They dynamically learn new routes.
B. They continously monitor the status of their own ports.
C. They exchange their entire neighbor tables with directly attached routers.
D. They exchange hello packets with their neighbors every five seconds, by default.
E. They compare known routes to received updates.

14. Which of the following statements are correct concerning the default configuration of a new switch? (Choose three.)
A. VLAN1 is configured with a management IP address.
B. All switch ports are assigned to VLAN1.
C. Spanning Tree Protocol is disabled.
D. All interfaces are set to auto.
E. Enable password is configured as cisco.
F. The flash directory contains the IOS image.

15. Which of the following are characteristics of link-state routing protocols? (Choose three.)
A. collection of routing information from within a defined area of the network
B. view of network from neighbor's perspective
C. independent calculation of best paths to all destinations
D. propagation of incorrect information minimized
E. demonstration of universal compatibility and simplicity

16. When the mode LED on a Cisco switch is set to STAT, what port status is indicated by a green flashing port LED?
A. no link
B. port is not forwarding
C. port is sending or receiving data
D. port is sending, but not receiving
E. link fault

17. Which type of address does OSPF use to initiate new adjacencies and to ensure that neighbor routers are functioning?
A. broadcast
B. loopback
C. multicast
D. unicast

[Hajime]

Chào cuongtran,

1)A, C
A: flood frames for unknown destinaiton là đặc tính của switch
C: thiết kết alternative route để tăng độ tin cậy

2)C
192.168.1.16 /28 mượn thêm 2 bit nữa làm subnet, do đề bài nói minimizing waste of address nên sẽ có thêm ip subnet-zero cho chính xác, vậy là ta sử dụng được 4 subnet

3) A
Mình dùng phương pháp loại suy, C, D chắc chắn sai, câu B thì không hiểu ý nó lắm nên mình chọn A. Nếu khác mode full/half duplex, thì sẽ không kết nối được.

5) A
heavy traffic thì chỉ có thể là broadcast storms thôi

6) C
Trong OSPF, neighbor adjacencies share routing information cho nhau

7) A, B và E
A, B thì “xiềng” rồi, có phải E là “ Authentication passwords or keys are different”: cái này mình không nhớ rõ lắm, để xem lại

8) E
Cái này thì “xiềng” rồi... Passive state là khi đã ở chế độ “ổn định và có thể sử dụng rồi”

10) B, E, F
Đây là những đặc điểm của việc chia VLAN

12) B
Đây củng là đặc điểm của default route

13) D
EIGRP duy trì neighbor bằng cách gửi các gói small hello packet mội 5 second bằng UDP

14) B, D, F
15) A, C, E
16) C
17) C

Còn các câu 4, 9, 11 mình không nghĩ ra câu trả lời chính xác, để mình xem lại sau.

Cám ơn,

[cuongtran]

Nào mời các bạn cùng nhau chung sức trả lời các câu hỏi, các bạn chỉ cần chọn câu đúng là A hoặc B hoặc A và C..., cảm ơn các bạn

1. Which strategies can a company take to enhance network reliability through redundancy? (Choose two.)
Eliminate single points of failure.
A. Flood frames for unknown destinations.
B. Send multiple frames to an end device.
C. Design alternate routes to a destination.
D. Forward MAC address tables to all switches on the network.
E. Eliminate multiple paths to the same destination.

2. The network 192.1.1.0 has been subnetted for a network design. The 192.1.1.16/28 subnet has been chosen for further subnetting to provide for point-to-point serial link addressing. How many serial link subnets can be created while minimizing the number of wasted addresses?
A. 1
B. 2
C. 4
D. 6
E. 8
F. 16

3. Using Telnet, a network administrator is unable to log in to a switch located at another office in order to make configuration changes to it. What could be the problem?
A. The managmement station does not have access to a full-duplex Fast Ethernet link on the switch.
B. VLAN 1 on the switch is not configured for TCP/IP network access.
C. The switch must be managed from the local LAN.
D. The switch hostname has not been set.

4. What is the term that describes the cabling between the MDF and IDF locations as shown in the graphic?

A. horizontal cross-connect
B. horizontal cross-cabling
C. vertical cross-connect
D. vertical cross-cabling

5. A switched Ethernet network is experiencing unusually heavy traffic to the extent that network delays have become intolerable. While investigating the problem, a network administrator disconnects a redundant uplink between two switches. The excessive traffic quickly subsides. What was the likely cause of this problem?

A. broadcast storms
B. routing loops
C. multiple frame copies
D. load balancing
E. unicast frame forwarding


6. What is required for OSPF routers to share routing information?
A. designated routers
B. a backup designated router
C. neighbor adjacencies
D. an NBMA network topology
E. links configured on the 224.0.0.0 network

7. Under which of the following circumstances might two routers have trouble establishing a neighbor relationship in an OSPF network? (Choose three.)
A. Hello packets are not sent from either neighbor.
B. The interfaces are on different network types.
C. The network command has put the connected interfaces into the same OSPF area.
D. Slow network connections cause OSPF advertisements to time out.
Authentication passwords or keys are different.

8. What is indicated when an EIGRP route is in the passive state?

A. The route has the highest path cost of all routes to that destination network.
B. The route must be confirmed by neighboring routers before it is put in the active state.
C. The route is a feasible successor and will be used if the active route fails.
D. There is no activity on the route to that network.
E. The route is viable and can be used to forward traffic.


9. Which of the following tasks must be completed to configure a router interface to serve the newly added network 192.168.10.64/27 and to advertise this network over RIP v2? (Choose three.)
A. Configure RIP v2 with the network command and the IP network number for the new network.
B. Configure RIP v2 with the network command and the IP host address and subnet mask for the newly activated interface.
C. Configure the router with the ip subnet-zero command so that this network can be added and advertised.
D. Apply a network host address and subnet mask to the newly activated interface.
E. Activate the routing protocol with the router rip version 2 command.
Configure RIP on the other routers in the enterprise with an entry for the newly added network.

10. What do switches configured with VLANs provide to an enterprise network? (Choose three.)
A. bridging between VLANs
B. security
C. broadcast control
D. physical grouping of users
E. logical grouping of users
F. enlargement of collison domains

11. How can MAC address table entries be removed from a switch? (Choose two.)
A. Power cycle the switch to clear all dynamically learned addresses.
The clear switching-tables command will remove statically configured entries.
B. The clear mac-address-table command will remove statically and dynamically configured table entries.
C. The erase flash command will clear all statically configured table entries.
D. Statically configured MAC addresses will automatically be removed from the address table 300 minutes after the last activity on a switch port.


12. What is the purpose of a default route?
A. A default route will cause packets addressed to unknown destination networks to be dropped.
B. A default route will cause packets addressed to unknown destination networks to be sent to a designated router interface.
C. A default route will cause packets addressed to known destinations to prefer a specified path to the destination network.
D. A default route will direct packets for all destination networks to a designated router and router interface.

13. How do EIGRP routers actively maintain neighbor relationships?
A. They dynamically learn new routes.
B. They continously monitor the status of their own ports.
C. They exchange their entire neighbor tables with directly attached routers.
D. They exchange hello packets with their neighbors every five seconds, by default.
E. They compare known routes to received updates.

14. Which of the following statements are correct concerning the default configuration of a new switch? (Choose three.)
A. VLAN1 is configured with a management IP address.
B. All switch ports are assigned to VLAN1.
C. Spanning Tree Protocol is disabled.
D. All interfaces are set to auto.
E. Enable password is configured as cisco.
F. The flash directory contains the IOS image.

15. Which of the following are characteristics of link-state routing protocols? (Choose three.)
A. collection of routing information from within a defined area of the network
B. view of network from neighbor's perspective
C. independent calculation of best paths to all destinations
D. propagation of incorrect information minimized
E. demonstration of universal compatibility and simplicity

16. When the mode LED on a Cisco switch is set to STAT, what port status is indicated by a green flashing port LED?
A. no link
B. port is not forwarding
C. port is sending or receiving data
D. port is sending, but not receiving
E. link fault

17. Which type of address does OSPF use to initiate new adjacencies and to ensure that neighbor routers are functioning?
A. broadcast
B. loopback
C. multicast
D. unicast

[Hajime]

To VoThanhDuy:


Các thiết bị có thể làm trunking là routers, switch và một server có gắn card mạng đặc biệt hỗ trợ trunking (dot1q). Các card mạng loại xịn của Intel/HP thường có hỗ trợ trunking như vậy

Vậy nếu việc trunking được support bởi isl thì server với NIC đặc biệt đó không thể kết nối trunk được à ? Ý mình muốn hỏi là: NIC đặc biệt đó chỉ support cho dot1q thôi à... tại mình chưa có kinh nghiệm thực tế lắm



Nếu một switch nhận một frame và địa chỉ source của frame này chưa biết, switch sẽ cập nhật địa chỉ source MAC vào port tương ứng trên switch


Chính xác là switch sẽ map source MAC trong frame bằng source MAC của port tương ứng trên switch

--- Câu trả lời của kokichi81 là chính xác, mình nghĩ câu đó đâu có khó lắm đâu vì nó là đặc điểm của switch mà... :)

To kokichi81:


Cho mình hỏi thiết bị CSU/DSU khác thiết bị NTU ở chỗ nào.
Vì mình từng thấy hai switch nối đường trunk với nhau qua NTU.

Ý bạn là : Switch1 ----- trunk----NTU------trunk-----Switch2 á ? ( tại vì nó nối trunk qua NTU mà )

Cám ơn, :)

[VoThanhDuy]

Hi Cường,

1. Để tăng tính dự phòng của một hệ thống mạng, bạn có thể thiết kế sao cho có nhiều đường đi về một đích. Các chọn lựa khác không phù hợp.

3. Để có thể telnet vào một switch, bạn phải đặt IP address cho interface VLAN 1.

4. Đoạn cáp nối giữa MDF/IDF được gọi là horizontal cross cable.

[kokichi81]

Mô hình mà minh thấy là :
Switch------NTU--------------------------------NTU-----Switch

[VoThanhDuy]

hi,

cấu hình theo kiểu trên không phải là trunking mà là bridging.

Lúc đó 2 cái NTU hoạt động bridging phải ko?

Thân chào,

[kokichi81]

Không phải!
Trên hai port của hai switch vãn cấu hình là trunk.
Còn NTU chi có trách nhiệm điều chế và giải điều chế tín hiệu thôi.
Vì đường truyền xa hơn 100m mà không muôn dùng cáp quang nên người ta mới dùng mô hình như vậy.
Như vâyvề căn bản giữa hai switch vẫn nối với nhau bằng trunk

Thân.

[danguyennhi]

hi kokichi81

Hai cái đó là NTU hay là HTU vậy?

Cám ơn nhé,

[khampha02]

Để chia VLAN, bạn có thể dùng cách chia theo port hoặc theo MAC. Cách chia theo port sẽ làm tăng tốc độ switch frame.

Cho hỏi vì sao chia theo port sẻ làm tăng tốc độ ?