What does a Layer 2 switch use to decide where to forward a received frame?()A. source MAC addressB. source IP addressC. source switch portD. destination IP addressE. destination port addressF. destination MAC address

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第2题：

What dose a Layer 2 switch use to decide where to forward a received frame?（）

• A、source MAC address
• B、source IP address
• C、source switch port
• D、destination IP address
• E、destination port address
• F、destination MAC address

正确答案:F

第3题：

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

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

正确答案:C

第4题：

What will an Ethernet switch do if it receives a unicast frame with a destination MAC that is listed in the switch table?（）

• A、The switch will not forward unicast frames.
• B、The switch will forward the frame to a specific port.
• C、The switch will return a copy of the frame out the source port.
• D、The switch will remove the destination MAC from the switch table.
• E、The switch will forward the frame to all ports except the port on which it was received.

正确答案:B

第5题：

For what two purposes does the Ethernet protocol use physical addresses？（）

• A、to uniquely identify devices at Layer 2
• B、to allow communication with devices on a different network
• C、to differentiate a Layer 2 frame from a Layer 3 packet
• D、to establish a priority system to determine which device gets to transmit first
• E、to allow communication between different devices on the same network
• F、to allow detection of a remote device when its physical address is unknown

正确答案:A,E

第6题：

What are two characteristics of "store and forward" switching?（）

• A、Latency fluctuates regardless of frame size.
• B、The switch receives the complete frame before beginning to forward it.
• C、Latency through the switch varies with frame length.
• D、The switch checks the destination address upon receipt of headers.

正确答案:B,C

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第12题：

If a switch is working in the fail-open mode， what will happen when the switch’s CAM table fills to capacityand a new frame arrives？（）

• A、A copy of the frame is forwarded out all switch ports other than the port the frame was received on.
• B、The frame is transmitted on the native VLAN.
• C、The switch sends a NACK segment to the frame’s source MAC address.
• D、The frame is dropped.

正确答案:A

第13题：

What does a Layer 2 switch use to decide where to forward a received frame?（）

• A、source MAC address
• B、source IP address
• C、source switch port
• D、destination IP address
• E、destination port address
• F、destination MAC address

正确答案:F

第14题：

Refer to the exhibit A frame on vlan 1on switch s1 is sent to switch s2 when the frame is received on vlan 2,what causes this behavior?（）

• A、trunk mode mismatches
• B、vlans that do not correspond to a unique IP subnet
• C、native vlan mismatches
• D、allowing only vlan 2 on the destination.

正确答案:C

第15题：

Why will as witch never learn a broadcast address？（）

• A、Broadcast frames are never sent to swiches.
• 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.

正确答案:C

第16题：

What does a Layer 2 switch do if it receives a frame with a destination MAC address that is not found in its MAC address table?（）

• A、The frame is dropped.
• B、The frame is addressed with a broadcast MAC address and sent out all ports.
• C、The frame is sent out all ports except the receiving port.
• D、An ARP request is sent out all ports except the receiving port.
• E、A destination unreachable message is sent back to the source address.
• F、None of the above.

正确答案:C

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