CCNA LAN Switching

CCNA Practice questions on LAN Switching

1. What would a switch do when it receives a frame with the source and destination mac-address as same.

a. The frame would be forwarded to all ports
b. The frame would be forwarded to the router.
c. The frame would be forwarded to the intermediate switch.
d. The frame would be discarded.

2. Which field would a switch add to its mac-address table when it receives a frame on its port

a. Destination mac-address
b. Source mac-address.
c. FCS
d. Type Value

3. What would happen when a switch receives an ARP request frame.

a. The frame would be sent to the intended reception
b. The frame would be sent to the router
c. The frame would be flooded to all ports on the switch
d. The frame would be broadcasted to all ports on the switch.

4. What would happen when a switch receives a DHCP Discover Packet on its switch port.

a. The packet would be dropped
b. The frame would be forwarded to the router
c. The frame would be broadcasted to all ports on the switch
d. None of the above.

Video Course – Layer 2 Switching & VLAN’s for Cisco CCNA

5. PC1 and PC2 belonging to different IP networks are connected to ports belonging to the same VLAN. Which of the following is true

a. PC1 can ping PC2
b. PC1 cannot ping PC2
c. PC1 can ping PC2 if the gateway of PC1 and PC2 is configured with the IP address of VLAN
d. PC1 can ping PC2 if the gateway of PC1 and PC2 is configured with the IP address of the switch.

6. Two switches are connected using a single link. Spanning tree is not configured on the switches. Which of the following events would occur.

a. Loop would occur
b. Loop would occur on the switch with the lowest mac-id
c. Loop would occur on the switch with the highest mac-id
d. Nothing would occur

7. Which of the following packets would not be able to cross to a different vlan

a. ARP Request
b. DHCP Discover
c. Unicast
d. Broadcast

Answers

1. When a switch receives a frame with source and destination mac-address as same , it would be discarded. This is known as filtering on the switch.

2. When a switch receives a frame it would add the source mac-address in the frame to the mac-address table.

3. ARP request frame is a broadcast frame. When a switch receives a broadcast frame, it would be broadcasted to all ports on the switch

4. DHCP Discover packet is a broadcast packet. This would the switch to broadcast the packet to all ports on the switch.

5. Since PC1 and PC2 are on different networks, irrespective of being on the same vlan, they would need a layer 3 device for intercommunication. So PC1 would be unable to ping PC2.

6. Spanning tree is required to be configured only when there are multiple links. In this case there is only a single link, due to which STP is not required. So no events would occur.

7. VLAN’s do not allow broadcast packets to travel to a different vlan. ARP request, DHCP Discover packets are broadcast packets. Only unicast packets are allowed.

Video Course – Layer 2 Switching & VLAN’s for Cisco CCNA

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Routing & Switching Basics