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Zorluk: OrtaL2 Switching Concepts and MAC Table Operation

A network workstation with MAC address 0010.7b33.44a1 is relocated from switch port GigabitEthernet0/1 to port GigabitEthernet0/2 on the same VLAN. Before the switch's MAC address table aging timer expires, the workstation sends an Ethernet frame out GigabitEthernet0/2 destined for a server with MAC address 0010.7b99.88c2. The server's MAC address is already dynamically mapped to port GigabitEthernet0/4 in the MAC address table. How does the switch process this incoming frame?

  1. The switch updates the MAC address table entry for 0010.7b33.44a1 to point to GigabitEthernet0/2, then forwards the frame directly out GigabitEthernet0/4.Cevap
  2. B
    The switch drops the frame because the source MAC address is registered on GigabitEthernet0/1 and creates a security violation.
  3. C
    The switch floods the frame out all active interfaces in the VLAN except GigabitEthernet0/2 because the MAC location changed.
  4. D
    The switch uses Layer 2 discovery protocols to verify the remote neighbor before updating the MAC address table entry.

Cevap

The switch updates the MAC address table entry for the moving host to reflect the new ingress port (GigabitEthernet0/2) and forwards the frame directly out the destination port (GigabitEthernet0/4).
When a switch receives a frame, it reads the source MAC address to update its MAC address table. If the source MAC address is already listed but associated with a different interface, the switch instantly updates the entry to point to the new ingress interface (GigabitEthernet0/2). Next, the switch looks up the destination MAC address. Because the destination MAC address (0010.7b99.88c2) is already known and mapped to GigabitEthernet0/4, the switch performs known unicast forwarding directly to GigabitEthernet0/4.

Adım Adım Çözüm

1
Examine the source MAC address and ingress interface of the incoming frame.
Source MAC 0010.7b33.44a1 arrives on GigabitEthernet0/2.
Switches inspect the source MAC address of every ingress frame to build and maintain the MAC address table.
2
Update the MAC address table entry if the source MAC is missing or associated with a different port.
The existing entry for 0010.7b33.44a1 is updated from GigabitEthernet0/1 to GigabitEthernet0/2.
Dynamic MAC learning automatically updates port associations when a host moves to a new switch port within the same VLAN.
3
Lookup the destination MAC address in the MAC address table to determine forwarding behavior.
Destination MAC 0010.7b99.88c2 is found mapped to GigabitEthernet0/4.
Known unicast frames are forwarded exclusively out the specific port mapped in the MAC address table.

Anahtar Kavram

Layer 2 MAC Address Table Learning and Forwarding Operations
Tahmini Süre:1m 0s
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Konular

L2 Switching Concepts and MAC Table Operation

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