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US 2003/0131182 A1
[0020] FIG. 1B is a block diagram illustrating an exem
plary storage area network in Which various embodiments of
the invention may be implemented.
[0021] FIG. 2 is a block diagram illustrating a virtualiZa
tion model that may be implemented in accordance With
various embodiments of the invention.
[0022] FIG. 3A is a block diagram illustrating an exem
plary virtualiZation sWitch in Which various embodiments of
the present invention maybe implemented.
[0023] FIG. 3B is a block diagram illustrating an exem
plary standard sWitch in Which various embodiments of the
present invention may be implemented.
[0024] FIG. 4 is a transaction ?oW diagram illustrating a
conventional method of implementing a node World Wide
name (NWWN) and port World Wide name (PWWN) for
each SCSI target port.
[0025] FIG. 5 is a block diagram illustrating an exemplary
virtual enclosure in accordance With one embodiment of the
invention.
[0026] FIG. 6 is a diagram illustrating an exemplary
system in Which a virtual enclosure is implemented through
the binding of the virtual enclosure ports to various virtu
aliZation ports in accordance With various embodiments of
the invention.
[0027] FIG. 7 is a process How diagram illustrating a
method of creating a virtual enclosure in accordance With
various embodiments of the invention.
[0028] FIG. 8 is a diagram illustrating a conventional ?bre
channel identi?er (FCID) that may be associated With a
virtual enclosure port in accordance With various embodi
ments of the invention.
[0029] FIG. 9 is a transaction ?oW diagram illustrating
one method of coordinating virtual enclosure binding and
trapping functionality of virtualiZation ports in accordance
With various embodiments of the invention.
[0030] FIG. 10 is a diagram illustrating an exemplary
table that may be maintained by a virtualiZation port indi
cating FCIDs to be handled by the virtualiZation port in
accordance With various embodiments of the invention.
[0031] FIG. 11 is a transaction ?oW diagram illustrating
one method of establishing communication betWeen a host
and one or more virtualiZation ports (e.g., virtual enclosure
ports, trapping ports) such that the host can access one or
more LUNs in accordance With various embodiments of the
invention.
[0032] FIG. 12 is a diagram illustrating an exemplary
LUN mapping table that may be used at step 1128 of FIG.
11 to perform LUN mapping.
[0033] FIG. 13 is a diagram representing a virtual enclo
sure corresponding to the LUN mapping table of FIG. 12.
DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENTS
[0034] In the folloWing description, numerous speci?c
details are set forth in order to provide a thorough under
standing of the present invention. It Will be obvious, hoW
ever, to one skilled in the art, that the present invention may
Jul. 10, 2003
be practiced Without some or all of these speci?c details. In
other instances, Well knoWn process steps have not been
described in detail in order not to unnecessarily obscure the
present invention.
[0035] In accordance With various embodiments of the
present invention, virtualiZation of storage Within a storage
area netWork may be implemented through the creation of a
virtual enclosure having one or more virtual enclosure ports.
The virtual enclosure is implemented, in part, by one or
more netWork devices, Which Will be referred to herein as
virtualiZation sWitches. More speci?cally, a virtualiZation
sWitch, or more speci?cally, a virtualiZation port Within the
virtualiZation sWitch, may handle messages such as packets
or frames on behalf of one of the virtual enclosure ports.
Thus, embodiments of the invention may be applied to a
packet or frame directed to a virtual enclosure port, as Will
be described in further detail beloW. For convenience, the
subsequent discussion Will describe embodiments of the
invention With respect to frames. SWitches act on frames and
use information about SANs to make sWitching decisions.
[0036] Note that the frames being received and transmitted
by a virtualiZation sWitch possess the frame format speci?ed
for a standard protocol such as Ethernet or ?bre channel.
Hence, softWare and hardWare conventionally used to gen
erate such frames may be employed With this invention.
Additional hardWare and/or softWare is employed to modify
and/or generate frames compatible With the standard proto
col in accordance With this invention. Those of skill in the
art Will understand hoW to develop the necessary hardWare
and softWare to alloW virtualiZation as described beloW.
[0037] Obviously, the appropriate netWork devices should
be con?gured With the appropriate softWare and/or hardWare
for performing virtualiZation functionality. Of course, all
netWork devices Within the storage area netWork need not be
con?gured With the virtualiZation functionality. Rather,
selected sWitches and/or ports may be con?gured With or
adapted for virtualiZation functionality. Similarly, in various
embodiments, such virtualiZation functionality may be
enabled or disabled through the selection of various modes.
Moreover, it may be desirable to con?gure selected ports of
netWork devices as virtualiZation-capable ports capable of
performing virtualiZation, either continuously, or only When
in a virtualiZation enabled state.
[0038] The standard protocol employed in the storage area
netWork (i.e., the protocol used to frame the data) Will
typically, although not necessarily, be synonymous With the
“type of traf?c” carried by the netWork. As explained beloW,
the type of traf?c is de?ned in some encapsulation formats.
Examples of the type of traf?c are typically layer 2 or
corresponding layer formats such as Ethernet, Fibre channel,
and In?niBand.
[0039] As described above, a storage area netWork (SAN)
is a high-speed special-purpose netWork that interconnects
different data storage devices With associated netWork hosts
(e.g., data servers or end user machines) on behalf of a larger
netWork of users. A SAN is de?ned by the physical con
?guration of the system. In other Words, those devices in a
SAN must be physically interconnected.
[0040] Within a storage area netWork 131 such as that
illustrated in FIG. 1B, various storage devices 132, 134,
136, 138, 140, and 142 may be implemented, Which may be