Ethernet switches make their forwarding decision based on what field of the Ethernet frame?
Question
Ethernet switches make their forwarding decision based on what field of the Ethernet frame?
Solution
Ethernet switches make their forwarding decisions based on the MAC (Media Access Control) address field of the Ethernet frame. Here are the steps:
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When a frame arrives at an Ethernet switch, the switch examines the destination MAC address of the frame.
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The switch then looks up this MAC address in its forwarding table, also known as a MAC address table or CAM (Content Addressable Memory) table.
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If the switch finds a match in its table, it forwards the frame out of the specific port associated with that MAC address.
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If the switch doesn't find a match in its table, it floods the frame out of all ports except the one it arrived on. This is known as unknown unicast flooding.
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The switch also learns from incoming frames. If it doesn't know the source MAC address of an incoming frame, it adds it to its forwarding table, associating it with the port the frame arrived on. This way, the switch builds its knowledge of what MAC addresses are associated with which ports.
Similar Questions
Which statement is correct about Ethernet switch frame forwarding decisions?Frame forwarding decisions are based on MAC address and port mappings in the CAM table.Cut-through frame forwarding ensures that invalid frames are always dropped.Unicast frames are always forwarded regardless of the destination MAC address.Only frames with a broadcast destination address are forwarded out all active switch ports.
Ethernet switches add entries to their MAC address table based on what field of the Ethernet frame?
Which three fields are found in an 802.3 Ethernet frame? (Choose three.)
Refer to the exhibit. The exhibit shows a small switched network and the contents of the MAC address table of the switch. PC1 has sent a frame addressed to PC3. What will the switch do with the frame?Group of answer choicesThe switch will discard the frame.The switch will forward the frame to all ports.The switch will forward the frame only to port 2.The switch will forward the frame only to ports 1 and 3.The switch will forward the frame to all ports except port 4.
When does a switch flood the network with a frame?When there is no MAC address associated with a switch port in the forward/filter tableWhen the frame uses the UDP protocolWhen it does not know the destination IP addressFor every frame
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