CCNA Tutorial 1.13 – Switching Concepts (MAC Learning, Switching, Flooding, MAC Table)
Quiz – CCNA 1.13 Switching Concepts
Multiple Choice (20 questions)
- What is the primary function of a switch in a LAN?
- A) Forward packets based on IP addresses
- B) Forward frames based on MAC addresses
- C) Encrypt traffic
- D) Provide routing between VLANs
- When a switch receives a frame, how does it learn the source MAC address?
- A) By looking at the IP header
- B) By examining the source MAC in the Ethernet frame
- C) By using ARP
- D) By querying the router
- The MAC address table is sometimes called the:
- A) Routing table
- B) Forwarding database (FDB)
- C) Access list
- D) DHCP lease table
- When a frame arrives with a destination MAC that is unknown, what does the switch do?
- A) Drops the frame
- B) Sends it only to the router
- C) Floods it out all ports except the incoming port
- D) Forwards it to the default gateway
- When a frame arrives with a destination MAC that is already in the table, the switch will:
- A) Flood it
- B) Forward it out the specific port in the table
- C) Drop it automatically
- D) Send it to all VLANs
- What happens when a MAC entry in the table has not been used for a period of time?
- A) It is permanently stored
- B) It is aged out and removed
- C) It is replaced by a broadcast
- D) It is converted into an IP address
- What is the default MAC aging time on most Cisco switches?
- A) 60 seconds
- B) 300 seconds (5 minutes)
- C) 600 seconds (10 minutes)
- D) Unlimited
- Which of these actions describes frame switching?
- A) Learning MAC addresses
- B) Looking up the destination MAC and forwarding to the correct port
- C) Aging out entries in the MAC table
- D) Flooding to all ports
- Which situation causes frame flooding?
- A) Destination MAC is unknown
- B) Source MAC is unknown
- C) Duplicate IP address detected
- D) Duplex mismatch
- Which type of traffic is always flooded by a switch?
- A) Broadcast traffic
- B) Unicast traffic
- C) Multicast traffic
- D) Routed traffic
- How does a switch prevent flooding for known destinations?
- A) By clearing ARP cache
- B) By maintaining a MAC address table
- C) By using NAT
- D) By sending frames to a router
- Which field in the Ethernet frame does a switch primarily use to make forwarding decisions?
- A) Source MAC
- B) Destination MAC
- C) VLAN ID
- D) EtherType
- What happens if two devices with the same MAC address appear in a network?
- A) The switch blocks one automatically
- B) The switch updates its MAC table with the most recent port
- C) Both devices communicate without issue
- D) The switch assigns new MACs
- Which of the following describes MAC learning?
- A) The process of resolving IP to MAC addresses
- B) Recording source MACs in the MAC address table
- C) Forwarding frames based on IP addresses
- D) Dropping frames without an IP header
- Which of the following is NOT a function of a MAC address table?
- A) Mapping MAC addresses to ports
- B) Reducing unnecessary flooding
- C) Determining IP routes
- D) Forwarding decisions
- Which command on a Cisco switch displays the MAC address table?
- A) show arp
- B) show mac address-table
- C) show ip route
- D) show vlan brief
- Which type of traffic uses a destination MAC of FF:FF:FF:FF:FF:FF?
- A) Broadcast
- B) Unicast
- C) Multicast
- D) Anycast
- Which of these is an example of multicast traffic in Ethernet?
- A) A DHCP request
- B) OSPF hello messages
- C) ARP requests
- D) ICMP echo requests
- If the MAC table becomes full, what will the switch do with new unknown destinations?
- A) Drop all traffic
- B) Forward only to routers
- C) Flood the frames
- D) Disable interfaces
- What is the main purpose of MAC aging?
- A) Improve routing decisions
- B) Keep the MAC table accurate and prevent stale entries
- C) Eliminate need for ARP
- D) Allow VLANs to function
Fill in the Blank (5 questions)
- A switch forwards frames based on the __________ MAC address in the frame.
- When a destination MAC is unknown, the switch __________ the frame.
- The database a switch uses to store learned MAC addresses is called the __________ table.
- The default MAC aging timer on most Cisco switches is __________ seconds.
- A frame smaller than 64 bytes is called a __________ frame.
Answer Key – CCNA 1.13 Switching Concepts
- B) Forward frames based on MAC addresses
- B) By examining the source MAC in the Ethernet frame
- B) Forwarding database (FDB)
- C) Floods it out all ports except the incoming port
- B) Forward it out the specific port in the table
- B) It is aged out and removed
- B) 300 seconds (5 minutes)
- B) Looking up the destination MAC and forwarding to the correct port
- A) Destination MAC is unknown
- A) Broadcast traffic
- B) By maintaining a MAC address table
- B) Destination MAC
- B) The switch updates its MAC table with the most recent port
- B) Recording source MACs in the MAC address table
- C) Determining IP routes
- B) show mac address-table
- A) Broadcast
- B) OSPF hello messages
- C) Flood the frames
- B) Keep the MAC table accurate and prevent stale entries
- Destination
- Floods
- MAC (or CAM)
- 300
- Runt