Page 12 of 18 Fibre Channel: Why another interface? March 2001 Because multiple devices cannot transfer data over the network at the same time, errors resulting from packet collisions and data loss are relatively infrequent and can be handled by the hardware. When transmission errors do occur, it is possible to retransmit just the affected frames; retransmitting the entire data stream is not required. A switched fabric is the most complex topology. It can be used to connect up to 16 million nodes, each of which is identified by a unique, world-wide name. In much the same way as a telephone call is routed from one side of the country to the other, the data passes from the originator, through a switch and into a “cloud” of interconnected networks. The path each data frame takes through the cloud is determined by switches throughout the cloud. When the frame reaches its destination, it moves out of the cloud to the recipient, where the frames that make up the data stream are reassembled and decoded. In a switched fabric, each data frame is transferred over a virtual point-to-point connection. There can be any number of full-bandwidth transfers occurring through the switch. Devices do not have to arbitrate for control of the network; each device can use the full available bandwidth. A switched fabric topology provides virtual point-to-point connections between any two communicating devices on the network A Fibre Channel switched fabric network operates in much the same way as the familiar long distance telephone network. Each data frame is transferred over a virtual point-to-point connection formed by a series of switches making up the fabric. p1   p2   p3   p4   p5   p6   p7   p8   p9   p10   p11   p12   p13   p14   p15   p16   p17   p18