A Cisco Catalyst switch with an initially empty MAC address table receives an Ethernet frame on ingress port FastEthernet0/1. The frame originates from Host A (MAC address 00A1.1111.AAAA) and is addressed to Host B (MAC address 00B2.2222.BBBB) on VLAN 10. In what chronological sequence does the Layer 2 switch execute internal processing steps from frame ingress to frame egress?
- 1Parse the ingress Ethernet frame on FastEthernet0/1 to extract the source MAC address (00A1.1111.AAAA) and destination MAC address (00B2.2222.BBBB).
- 2Lookup the source MAC address (00A1.1111.AAAA) in the MAC table and create a dynamic entry binding 00A1.1111.AAAA to port FastEthernet0/1 on VLAN 10.
- 3Perform a MAC address table lookup for the destination MAC address (00B2.2222.BBBB) within VLAN 10.
- 4Identify the destination MAC address as unknown unicast due to a lookup miss in the MAC address table.
- 5Flood the frame out all active switchports belonging to VLAN 10, explicitly excluding ingress port FastEthernet0/1.
Cevap
The correct chronological sequence is: 1) Parse ingress frame for MAC addresses, 2) Learn source MAC and map to ingress port, 3) Lookup destination MAC in table, 4) Identify destination as unknown unicast, 5) Flood frame out all VLAN ports except ingress port.
When a Layer 2 switch receives an Ethernet frame on an ingress interface, it processes the frame in a specific order: first, it parses the L2 header; second, it reads the source MAC address and updates/populates its MAC address table (CAM table); third, it looks up the destination MAC address; fourth, if the destination is missing from the CAM table, it classifies it as an unknown unicast; fifth, it floods the frame out all active ports assigned to that VLAN except the receiving port.
Adım Adım Çözüm
Anahtar Kavram
Layer 2 MAC Address Table Operation and Ingress/Egress Forwarding Pipeline