Magnum 500-Series Switching Hubs | Installation and User Guide (08/98) |
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2.2.3 100Mb/s Fiber Port, ST or SC type (Single-Mode or Multi-Mode)100Mb1@
ST Connector (Magnum 528F-ST)
SC Connector (Magnum 528F-SC)
1 @ 100Mb Fiber port, type ST or SC (Magnum 528F models only)
The two Fast Ethernet switched ports on the Magnum 528F normally are set (by factory default) to operate at fixed 100Mb speed for guaranteed high-speed performance. The 528F’s fiber ports can be connected using a multi-mode ST, SC or single-mode ST, SC connector. In the factory-default setting, each of the 100Mb RJ-45 ports and/or the 100Mb Fiber port will run at 100Mb/s speed at all times
On the Magnum 528 and 528F models, the user may select full- or half-duplex mode per-port with a manual switch for flexibility to adapt to any type of Fast Ethernet devices. The Full/Half-duplex manual switches are located on the front panel under the corresponding Fast Ethernet ports for convenient access.
On Magnum 528F units, there are three LED’s per Fiber Optic port. One (LK) indicates ready for operation at 100Mb when lit, one indicates operation in full-duplex mode when ON (when it is OFF, operation is half-duplex), and one indicates Receiving Activity (RX). A fiber cable must be connected to each 100Mb port and a proper link (LK lit) must be made with the device at the other end of the cable in order for these LEDs to provide valid indications of operating conditions.
2.2.3Frame Buffering and Latency
The Magnum 500-Series are store-and-forward switches. Each frame (or packet) is loaded into the Magnum 500’s memory and inspected before forwarding can occur. This technique ensures that all forwarded frames are of a valid length and have the correct CRC, i.e., are good packets. This eliminates the propagation of bad packets, enabling all of the available bandwidth to be used for valid information.
While other switching technologies such as "cut-through" or "express" impose minimal frame latency, they will also permit bad frames to propagate out to the Ethernet segments connected. The "cut-through" technique permits collision fragment frames, which are a result of late collisions, to be forwarded to add to the network traffic. Since
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