In-Band vs. Out of-Band Virtualization
“In Band” means that the control data (metadata) and user data are in
the same path, in the main data path. For example, in an “in-band”
network-based FC storage virtualization implementation both control
data (metadata) and user data travel through the FC network.
“Out of Band” means that the control data DOES NOT travel through
the same main data path (“band”) as the user data. In an “out-of-band”
FC storage virtualization system, for example, the control data
(metadata) could travel out of the main data path, across an Ethernet
network, whereas the user data travels thought the FC network.
However, not all Asymmetric virtualization implementations are out-of-
band. For example, in an “out-of-band” network-based FC storage
virtualization implementation the control data (metadata) could still pass
though FC links to the Virtualization Manager, but take a different path to
the user data. This would be an example of an in-band asymmetric
implementation of storage virtualization.