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Zorluk: OrtaL2 Switching Concepts and MAC Table Operation

Host-X sends an Ethernet frame destined for Host-Y through a Cisco Catalyst switch. The switch receives the frame on interface FastEthernet0/2. At the time of arrival, Host-X's source MAC address is not present in the switch MAC address table, while Host-Y's destination MAC address is already mapped to FastEthernet0/8. Place the internal processing steps performed by the Layer 2 switch in the correct chronological sequence from first to last.

  1. 1Ingress frame containing source MAC-X and destination MAC-Y arrives on interface FastEthernet0/2.
  2. 2The switch extracts source MAC-X and creates a dynamic binding entry for MAC-X associated with FastEthernet0/2 in the MAC address table.
  3. 3The switch performs a lookup in its MAC address table using destination MAC-Y.
  4. 4The switch identifies a matching entry mapping destination MAC-Y directly to egress interface FastEthernet0/8.
  5. 5The switch forwards the frame exclusively out of interface FastEthernet0/8 as a known unicast transmission.

Cevap

The correct chronological sequence begins with receiving the frame on FastEthernet0/2, followed by learning the source MAC address (MAC-X), performing a table lookup for the destination MAC address (MAC-Y), matching MAC-Y to FastEthernet0/8, and finally forwarding the frame solely out interface FastEthernet0/8.
The correct order follows standard Cisco Layer 2 switching logic: 1) Ingress frame reception on interface FastEthernet0/2; 2) Source MAC address inspection and MAC table entry creation for FastEthernet0/2; 3) Destination MAC address table lookup; 4) Identification of egress port FastEthernet0/8; 5) Unicast transmission out FastEthernet0/8.

Adım Adım Çözüm

1
Receive Ingress Frame
The switch physical port FastEthernet0/2 accepts the frame header containing source MAC-X and destination MAC-Y.
Layer 2 processing requires the physical frame to enter an ingress interface first.
2
Source MAC Learning
Source MAC-X is mapped to FastEthernet0/2 in the switch MAC address table.
Switches update or populate their CAM/MAC table based on ingress source MAC addresses.
3
Destination MAC Lookup
The switch queries the MAC address table for destination MAC-Y.
The switch needs to decide whether to flood or unicast-forward the ingress frame based on destination MAC state.
4
Match Egress Port
The lookup resolves MAC-Y to interface FastEthernet0/8.
A matching entry prevents unknown unicast flooding.
5
Unicast Frame Forwarding
The frame is transmitted directly out FastEthernet0/8.
Known unicast destination entries result in single-port forwarding.

Anahtar Kavram

Layer 2 Ethernet Switching Process and MAC Address Table Learning and Forwarding Logic
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