Chapter 1: Overview

Smart

MissingLink

Mode

switches, one local and the other remote. Switch 1, the remote switch, is connected to port 1, the fiber optic port, on the media converter, while Switch 2, the local device, is connected to port 2, the twisted pair port. If the link to Switch 1 is lost, the line card disables the transmitter on port 2 to signal Switch 2 of the loss of the link to Switch 1. This notifies Switch 2 of the problem so it too, along with Switch 1, can take remedial action, such as activating a redundant path if it is running a spanning tree protocol, or sending an SNMP trap to a management workstation. Without the MissingLink mode, Switch 2 would be unaware of the problem because it would still have a valid link to the media converter.

In the example the initial loss occurred on port 1. But the operating mode operates the same when the initial loss of the link is on port 2. Here, the transmitter on port 1 is disabled to notify the node connected to that port of the loss of the link on port 2.

The states of the ports on the media converter running in this mode operate in tandem. Either both of the ports have a link or neither of the ports. This is reflected on the Link LEDs. If both ports can form links with their network devices, their Link LEDs will both be on. But if one or both ports cannot establish a link, then the Link LEDs will be off.

This operating mode is most useful when the network devices connected to the ports of the media converter can react to a loss of a link on a port, such as managed Fast Ethernet switches running SNMP or a spanning tree protocol. Conversely, the MissingLink mode will be of little value if the network devices of the media converter cannot react to a lost link. In the latter scenario, the Link Test mode would probably be a better operating mode for the media converter during normal network operations.

Furthermore, Allied Telesis does not recommend using the MissingLink mode when troubleshooting a network problem that may have its roots with a link problem. The MissingLink mode will not allow you to use the port’s Link LEDs or the management software to diagnose the problem, since neither port will show a link. Rather, the Link Test and the Smart MissingLink modes are more useful when troubleshooting a link problem.

The Smart MissingLink mode is nearly identical to the MissingLink mode. It, too, enables the two ports on the media converter to share the link status of their connections. This mode is different in that it does not completely shut off the transmitter of a port when the companion port loses its link. Rather, this operating mode pulses the port’s transmitter and flashes the port’s Link LED once a second to signal that the port can still establish a link to its network device and that the loss of the link originated on the companion port on the media converter.

The advantage of this operating mode over the MissingLink mode is that you can use the Link LEDs on the media converter to troubleshoot a link failure with the ports. As an example, assume that the fiber optic port on a media converter lost its link to its network device. The mode would

22

Page 21 Page 23
Page 22
Image 22
Allied Telesis AT-PC232/POE manual Smart MissingLink Mode
Page 21 Page 23

AT-PC232/POE specifications

Allied Telesis AT-PC232/POE is a versatile and robust power-over-Ethernet (PoE) switch that effectively meets the needs of small to medium-sized networks. Designed for user-friendly operation and scalability, this switch caters to the increasing demand for power and data connectivity in various environments, from small offices to larger enterprise applications.

One of the main features of the AT-PC232/POE is its capability to deliver both data and electrical power over a single Ethernet cable. This functionality simplifies installations of network devices such as IP cameras, VoIP phones, and wireless access points, reducing cabling costs and improving site aesthetics. The switch can supply up to 15.4 watts of power per port, adhering to the IEEE 802.3af PoE standard. This enables straightforward connection to devices without needing additional power sources, making it a convenient choice for businesses looking to streamline their operational efficiency.

In terms of design, the AT-PC232/POE is compact and rack-mountable, allowing for efficient use of space in server rooms and network closets. Its fanless operation ensures quiet performance, making it suitable for noise-sensitive environments. The switch is also equipped with LED indicators that provide at-a-glance updates on power status, network activity, and port statistics.

The AT-PC232/POE utilizes advanced networking technologies such as VLAN (Virtual Local Area Network) support and QoS (Quality of Service). VLAN support allows network administrators to segment network traffic for better performance and security, while QoS capabilities prioritize critical data packets, ensuring that important applications such as video conferencing and VoIP operate smoothly without interruption.

Another significant characteristic of this switch is its management capabilities. Allied Telesis provides a web-based graphical user interface (GUI) for easy configuration and monitoring, allowing administrators to quickly set up networks and troubleshoot issues. Security features such as port security and access control lists help prevent unauthorized access and ensure that the network remains secure.

In summary, the Allied Telesis AT-PC232/POE switch combines efficient power delivery with sophisticated networking features, making it an excellent choice for businesses looking to enhance their network infrastructure. Its compact design, ease of use, and management capabilities position it as a reliable solution for modern networking demands.
Top Page Image Contents