Page 13 of 18
March 2001
Fibre Channel: Why another interface?
The bridge shortcut
Currently, the most common method for attaching tape drives and libraries
to a Fibre Channel network is to attach traditional SCSI devices to a
SCSI-to-Fibre Channel bridge (sometimes called a router). The bridge
converts the SCSI signals into the Fibre Channel frames and then
transmits the frames through a Fibre Channel switch or hub to the Fibre
Channel network. Using a bridge provides a quick way to attach legacy
SCSI devices into a Fibre Channel network. In addition, some bridges
enable use of the extended copy (E-copy) SCSI command on tape drives.
Using a bridge to provide Fibre Channel connectivity does have its
limitations. Connecting multiple devices (for example, the tape drives and
robot in a library) to a Fibre Channel network through a single bridge can
cause a performance bottleneck. In this type of configuration, all of the
devices must share the available bandwidth through the single link to the
Fibre Channel network. Furthermore, bridges tend to be expensive and can
be complex to properly configure. Adding new devices means
reconfiguring the existing bridge or purchasing a new bridge to provide the
necessary bandwidth. In addition, when multiple devices are attached to
the network through a single bridge, failure of the bridge takes all of the
attached devices off the network.
A FIbre Channel-to-SCSI bridge connects traditional SCSI devices to a
Fibre Channel network
Although Fibre Channel-to-
SCSI bridges can be
expensive to implement, they
provide instant Fibre
Channel connectivity for
legacy SCSI devices.
p1
p2
p3
p4
p5
p6
p7
p8
p9
p10
p11
p12
p13
p14
p15
p16
p17
p18