Fabric OS Administrator's Guide v7.0.0 (53-1002148-02, June 2011)

468 Fabric OS Administrator’s Guide
53-1002148-02
Fibre Channel routing concepts
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To do so, at least one translate phantom domain is created in the backbone fabric. This
translate phantom domain represents the entire edge fabric. The shared physical devices in
the edge have corresponding proxy devices on the translate phantom domain.
Each edge fabric has one and only one xlate domain to the backbone fabric. The backbone
fabric device communicates with the proxy devices whenever it needs to contact the shared
physical devices in the edge. The FC-FC Routing Service receives the frames from the
backbone switches destined to the proxy devices, and redirects the frames to the actual
physical devices. When connected to edge fabrics, the translate phantom domain can never be
the principal switch of the backbone fabric. Front domains are not created; rather, only
translate phantom domains are created in the backbone fabric.
Devices are exported from the backbone fabric to one or more edge fabrics using LSANs. See
“LSAN zone configuration” on page 480 for more information.
Phantom domains
A phantom domain is a domain created by the Fibre Channel router. The FC router creates two
types of phantom domains: front phantom domains and translate phantom domains.
A front phantom domain, or front domain, is a domain that is projected from the FC router to the
edge fabric. There is one front phantom domain from each FC router to an edge fabric, regardless
of the number of EX_Ports connected from that router to the edge fabric. Another FC router
connected to the same edge fabric projects a different front phantom domain.
A translate phantom domain, also referred to as translate domain or xlate domain, is a router
virtual domain that represents an entire fabric. The EX_Ports present xlate domains in edge fabrics
as being topologically behind the front domains; if the xlate domain is in a backbone fabric, then it
is topologically present behind the FC router because there is no front domain in a backbone fabric.
If an FC router is attached to an edge fabric using an EX_Port, it creates xlate domains in the fabric
corresponding to the imported edge fabrics with active LSANs defined. If you import devices into
the backbone fabric, then an xlate domain is created in the backbone device in addition to the one
in the edge fabric.
Figure 78 on page 468 shows a sample physical topology. This figure shows four FC routers in a
backbone fabric and four edge fabrics connected to the FC routers.
FIGURE 78 Sample topology (physical topology)
Fabric 1
Fabric 2
Fabric 3
Fabric 4
Host Target 1 Target 2 Target 3
FC router 1 FC router 4FC router 3FC router 2
EX
E
EX
EX
EX
EX
EX
EX
E
E
E
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E