Which Statement is Correct about Ethernet Switch Frame Forwarding Decisions
I. Introduction
Ethernet switches are essential networking devices that play a crucial role in forwarding data packets across a Local Area Network (LAN). When a switch receives an Ethernet frame, it must make a decision on how to handle and forward it based on various factors. In this article, we will explore the correct statement about Ethernet switch frame forwarding decisions.
II. Frame Forwarding Decisions
Ethernet switches employ different methods to determine the appropriate destination for an incoming frame. One commonly used method is known as MAC address learning.
III. MAC Address Learning
Ethernet switches maintain a table, known as the MAC address table or CAM table, which maps MAC addresses to their corresponding ports. When a frame enters the switch, it examines the source MAC address in the Ethernet header.
If the MAC address is not already in the CAM table, the switch adds an entry for it, associating it with the port through which it arrived. This process is called MAC address learning. By dynamically building the CAM table, the switch can keep track of which devices are connected to which ports.
IV. Frame Forwarding
Once the switch has learned the MAC addresses and associated ports, it can make informed decisions on how to forward frames. The switch compares the destination MAC address of an incoming frame to its CAM table entries.
If there is a match, indicating that the MAC address is already in the table, the switch knows which port the frame should be forwarded to. The switch then forwards the frame only to the port associated with the destination MAC address.
If there is no match in the CAM table, the switch broadcasts the frame to all ports except the one it arrived on. This is known as flooding. The destination device, if present, will receive the frame and update its CAM table entry accordingly.
V. Correct Statement
With the understanding of MAC address learning and frame forwarding, we can now determine the correct statement about Ethernet switch frame forwarding decisions.
The correct statement is that Ethernet switches use the destination MAC address in the Ethernet frame to decide which port to forward it to. By comparing the destination MAC address with entries in the CAM table, the switch can efficiently deliver frames directly to the intended recipient’s port.
VI. Conclusion
Ethernet switch frame forwarding decisions are crucial for efficient data transmission in a LAN. By employing MAC address learning and CAM tables, switches can determine the appropriate port for each incoming frame. The correct statement about Ethernet switch frame forwarding decisions is that the destination MAC address is used to decide the port for forwarding. This ensures accurate and efficient delivery of data packets within the network.
