Mdi/Mdi-X

Overview

Duplex Mode

Auto

Store and

Forward

Back Pressure and Flow Control

Duplex mode refers to how an end node receives and transmits data. If an end node can receive or transmit data, but not both simultaneously, it is operating in what is referred to as half-duplex mode. If an end node can both receive and transmit data simultaneously, the end node is said to be operating in full-duplex mode. Naturally, an end node capable of operating in full-duplex can handle data much faster than an end node that can only operate in half-duplex mode.

The twisted pair ports on the AT-9000/28 Gigabit Ethernet ecoSwitch can operate in either half-or full-duplex mode. They are IEEE 802.3u- compliant and use Auto-Negotiation to set the duplex mode setting for you automatically.

For Auto-Negotiation to operate properly on a switch, the end nodes connected to the switch should also use Auto-Negotiation. If an end node does not have this feature and has a fixed duplex mode of full-duplex, the result will be a duplex mode mismatch between the end node and a switch port. A port on the Gigabit Ethernet switch connected to an end node with

afixed duplex mode of full-duplex will operate at only half-duplex. This results in the end node using full-duplex and the switch port using half- duplex. This can produce network performance problems. If you encounter this situation, you must configure the port on the end node to use Auto-Negotiation or, if it lacks that feature, to half-duplex.

The auto-MDI/MDI-X feature on the twisted pair ports automatically configures the MDI/MDI-X setting when a link is established with an end node. Available when a port is at the default setting of Auto-Negotiation, this feature allows you to use a straight-through twisted pair cable when connecting any type of network device to a port.

Disabling Auto-Negotiation on a port and setting the speed and duplex mode manually also disables the auto-MDI/MDI-X feature. A port where Auto-Negotiation has been disabled defaults to MDI-X. Disabling Auto- Negotiation may require manually configuring a port’s MDI/MDI-X setting or using a crossover cable. For instructions on how to configure a port, refer to the AT-S100 Management Software User’s Guide.

The AT-9000/28 Gigabit Ethernet ecoSwitch uses store and forward as the method for receiving and transmitting frames. When a Ethernet frame is received on a switch port, the switch does not retransmit the frame out the destination port until it has received the entire frame and stored the frame in a port buffer. It then examines the frame to determine if it is a valid frame. Invalid frames, such as fragments or runts, are discarded by the switch. This insures that only valid frames are transmitted out the switch ports and that damaged frames are not propagated on your network.

To maintain the orderly movement of data between the end nodes, an Ethernet switch may periodically need to signal an end node to stop

AT-9000/28 specifications

The Allied Telesis AT-9000/28 is a versatile and robust network switch designed for organizations seeking to enhance their networking capability. This Layer 2 managed switch delivers a high degree of performance and reliability, making it an ideal choice for businesses that require a seamless network experience.

One of the main features of the AT-9000/28 is its 28 ports, which include 24 Fast Ethernet ports and 4 Gigabit Ethernet uplink ports. This allows for flexible network configuration and scalability, accommodating both wired and wireless devices efficiently. The switch also supports auto-negotiation and auto-MDI/MDI-X, which simplifies installation and connectivity by automatically detecting and configuring the appropriate settings.

The AT-9000/28 employs advanced switching technologies, such as IEEE 802.1Q VLAN tagging, which enables the segregation of traffic for improved security and performance. This feature is crucial for businesses that require data isolation between different departments or user groups. In addition, the switch supports quality of service (QoS) protocols, allowing for traffic prioritization. This is particularly beneficial for organizations that handle multimedia applications or VoIP services that demand reliable bandwidth.

Another significant characteristic of the AT-9000/28 is its support for port mirroring. This capability is essential for network monitoring and troubleshooting, as it allows administrators to track and analyze network traffic efficiently. Furthermore, the switch supports multiple user authentication methods, including RADIUS and TACACS+, thus enhancing network security.

The AT-9000/28 is built with energy efficiency in mind, featuring Energy Efficient Ethernet (EEE) technology. This reduces power consumption during periods of low traffic without compromising performance, which aids in lowering overall operational costs.

In terms of management, the AT-9000/28 offers versatile management options, including a web-based GUI, Command Line Interface (CLI), and SNMP support. This flexibility enables network administrators to configure, monitor, and troubleshoot the switch easily.

Overall, the Allied Telesis AT-9000/28 is a reliable switch well-suited for a variety of network environments. Its combination of performance, security features, and energy efficiency makes it an excellent choice for organizations looking to optimize their network infrastructure. With robust capabilities and advanced technologies, the AT-9000/28 stands out as a valuable addition to any networking setup.