Ethernet MAC transmits frames in half-duplex and full-duplex ways. In half- duplex operation mode, the MAC can either transmit or receive frame at a moment, but cannot do both jobs at the same time.

As the transmission of a MAC frame with half-duplex operation exists only in the same collision domain. The carrier signal needs to spend time to travel and reach the target device. The worst case occurs when two most-distanced devices in the same collision domain; one sends the frame first and the other sends the frame right before the frame from first device arrives. The collision happens and will be detected by the second device immediately. Because of the medium delay, this corrupted signal needs to spend some time to propagate back to the first device. The maximum time to detect a collision is approximately twice the signal propagation time between the two most-distant devices. This maximum time is traded-off by the collision recovery time and the diameter of the LAN.

In the original 802.3 specification, Ethernet operates in half duplex only. Under this condition, when in 10Mbps LAN, it’s 2500 meters, in 100Mbps LAN, it’s approximately 200 meters and in 1000Mbps, 200 meters. Theoretically, the LAN diameter should be 20 meters. However, in practice the LAN diameter of 200 meters is kept by increasing the minimum frame size with a variable-length, non- data extension bit field, which is removed by the receiving MAC. The following tables are the frame format suitable for 10M, 100M and 1000M Ethernet, and some parameters that shall be applied to all of these three types of Ethernet.

Actually, the Gigabit Ethernet chips in practice do not support this feature at the moment. All chips, and as well as all network vendors' devices, support full- duplex mode only. It is safe to say that this criterion does not exist for both present time and in the future. The switch’s Gigabit module supports only full-duplex mode.

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Fig. 3-4 Gigabit Ethernet Frame

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ES-5240G+ specifications

Edimax Technology ES-5240G+ is a highly versatile and efficient Ethernet switch designed to cater to the networking needs of small to medium-sized businesses and home offices. With its robust features and reliable performance, this switch is an essential component for a seamless network infrastructure.

One of the standout features of the ES-5240G+ is its 24 10/100/1000Mbps Gigabit Ethernet ports. This allows for high-speed connectivity, enabling users to transfer large files quickly and efficiently. The switch is equipped with a non-blocking architecture, ensuring that all ports can be utilized simultaneously without any reduction in bandwidth. This is particularly beneficial for businesses that rely on high-speed internet and internal networks for their daily operations.

The ES-5240G+ supports advanced Layer 2 switching features, including VLAN (Virtual Local Area Network) support, port mirroring, and link aggregation. These features enhance network management and optimization, making it easier to segment network traffic and improve security. With VLAN support, users can create separate networks within the same switch, leading to improved performance and reduced broadcast traffic.

Moreover, the ES-5240G+ incorporates IEEE 802.3x Flow Control, which helps to prevent data loss during heavy traffic periods. This technology allows for effective communication between devices and ensures smooth data transmission, even in congested network environments. Additionally, the switch is equipped with Automatic MDI/MDI-X detection, eliminating the need for crossover cables and simplifying installation.

From a security perspective, Edimax has included features such as address filtering and port security, which help to protect the network from unauthorized access. The switch can restrict access to specific MAC addresses, providing an added layer of security for sensitive data.

In terms of energy efficiency, the ES-5240G+ is designed to comply with IEEE 802.3az Energy Efficient Ethernet standards. This technology helps to reduce power consumption during low-traffic periods, making it an eco-friendly choice for businesses looking to minimize their carbon footprint.

Overall, Edimax Technology ES-5240G+ stands out as a reliable and efficient Ethernet switch, equipped with a range of features that enhance network performance and security. Its capabilities make it an ideal choice for businesses seeking to streamline their networking infrastructure and improve operational efficiency.
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