| A fabric switch is a switch which has fiber optic inputs and outputs. It is a crossbar switch, which means several devices, like servers, or servers and storage can communicate at the same time when they are connected to it. Popular sizes for fabric switches are 8 ports and 16 ports, and as many as 32 or 64. Fabric switches are expensive, the 64 port getting up to or over $100K. Brocade and McData do well with these. By far more of the 8s and 16s are sold. The next "lower" switch on the totem pole, the fibre channel arbitrated loop switch, or simply loop switch, is much cheaper, but devices have to arbitrate and, therefore, wait to get hold of the switching media and transmit through it to some other device. Before these two kinds of switches, hubs predominated. These three types of switches are the boxes that typically sit between servers and storage in a SAN, storage area network, which is rapidly gaining use and replacing direct attached storage (storage boxes attached directly by cables to servers). Again, fabric switches are the best and fastest (and most expensive) of the switch types. |
