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Zorluk: KolaySwitching Concepts and VLANs

A network switch receives an Ethernet frame on port 3 destined for a specific host. However, the destination MAC address is not currently stored in the switch's MAC address table. How will the switch handle this incoming frame?

  1. It floods the frame out all active switch ports assigned to the receiving port's VLAN, except port 3.Cevap
  2. B
    It forwards the frame out every physical port on the switch regardless of VLAN boundary assignments.
  3. C
    It sends the frame directly to the default gateway router so Layer 3 can resolve the unknown destination MAC address.
  4. D
    It automatically strips the 802.1Q tag from the frame header and forwards it exclusively over the native VLAN trunk link.

Cevap

The switch floods the frame out all active ports belonging to the same VLAN as the ingress port, excluding the ingress port itself.
When a Layer 2 switch receives a unicast frame destined for a hardware address not currently listed in its MAC address table, it performs unknown unicast flooding. To guarantee delivery while maintaining security and segmentation, the switch forwards the frame to every active port assigned to the same VLAN, excluding the ingress port on which the frame arrived.

Adım Adım Çözüm

1
Examine the destination MAC address in the incoming frame header.
The destination address is evaluated against the switch's internal Content Addressable Memory (CAM) / MAC address table.
Layer 2 switches make forwarding decisions based on source and destination MAC addresses.
2
Determine the lookup result when the MAC address is absent.
The frame is categorized as unknown unicast traffic.
Because the MAC address table lacks an entry associating the destination address with a specific egress port, the switch cannot perform targeted unicast forwarding.
3
Apply the unknown unicast forwarding rule within the ingress port's VLAN.
The frame is duplicated and transmitted out all operational switch ports in the same VLAN, except the receiving port.
Flooding ensures the intended destination device receives the frame and can reply, allowing the switch to learn its MAC address position for future frames while respecting VLAN isolation.

Anahtar Kavram

Unknown Unicast Flooding
Tahmini Süre:45s
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Switching Concepts and VLANs

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