Chapter 3: Local Management
3.9.1Full Duplex FDDI
Full duplex FDDI is the creation of a 200 Mbps point-to-point link between two FDDI devices that support full duplex FDDI operation. Full duplex FDDI is a technology where the end devices simultaneously transmit and receive data at 100 Mbps. For the HSIM-F6 to operate in full duplex mode, specific criteria must be met. Before configuring the HSIM-F6 to operate in full duplex mode, ensure that the network configuration meets the following requirements.
•The FDDI device that connects to the HSIM-F6 must be a Cabletron Systems product that supports full duplex FDDI (e.g., 9F426-02 MMAC-Plus SmartSwitch module, or another HSIM-F6).
•Full duplex FDDI is a point-to-point link between two devices that support full duplex operation. No other stations may be present on the ring. If a third station is added, the HSIM-F6 automatically returns to standard FDDI operation.
•There must be two FPIMs installed in the HSIM-F6 to connect to the other full duplex FDDI device. To operate in full duplex mode, one port transmits data while the other receives data simultaneously. Cabletron Systems recommends that the connection between the two devices be made from the A port of one device, to the B port of the other.
Making a connection between the A ports of both devices to the B ports of both devices (as is done with a DAS in normal FDDI operation) DOES NOT create a redundant path when using full duplex FDDI.