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Upgrade and downgrade considerations for FC-FC routing 21
Even though F_Ports are not allowed in the base switch, they are allowed in an FC router in legacy
mode (Fabric OS v6.1.x or earlier, or Fabric OS v6.2.0 or later with Virtual Fabrics disabled). If you
connect an FC router in legacy mode to the base switch, backbone-to-edge routing is supported on
that FC router.
In Figure 76, no devices can be connected to the backbone fabric (Fabric 8) because base switches
cannot have F_Ports. Figure 78 shows an FC router in legacy mode connected to a base switch.
This FC router can have devices connected to it, and so you can have backbone-to-edge routing
through this FC router. In this figure, Host A in the backbone fabric can communicate with device B
in the edge fabric with FID 20; Host A cannot communicate with device C, however, because the
base switches do not support backbone-to-edge routing.
FIGURE 78 Backbone-to-edge routing across base switch using FC router in legacy mode

Upgrade and downgrade considerations for FC-FC routing

When you upgrade to Fabric OS v6.4.0 or later, EX_Ports remain functional and you can continue to
perform all FC router operations on the switch.
Brocade recommends that you save your FC-FC routing configuration (using the configUpload
command) before performing any downgrades.
For further instructions on downgrading, refer to Chapter 9, “Installing and Maintaining Firmware”.

How replacing port blades affects EX_Port configuration

If you replace an FR4-18i blade with an 8-Gbps port blade or FX8-24 blade, the EX_Port
configuration remains the same for the first 16 ports on the 8-Gbps port blade (and for the first 12
FC ports on the FX8-24 blade). For all other ports on the blade, the EX_Port configuration is
cleared. No ports are persistently disabled.
Logical switch 8
(Base switch)
Fabric ID 8
Logical switch 7
Fabric ID 15
Logical switch 6
Fabric ID 1
Allows XISL use
Logical switch 5
(Default logical switch)
Fabric ID 128
Physical chassis 2
Logical switch 4
(Base switch)
Fabric ID 8 E
Logical switch 3
Fabric ID 15 E
Logical switch 2
Fabric ID 1
Allows XISL use
E
Logical switch 1
(Default logical switch)
Fabric ID 128
E
Physical chassis 1
E
E
E
XISL
EX EX
F
F
E
IFL
IFL
ISL
ISL
E ISL
FC router
Fabric ID 4
E
EX
IFL

A

B

C

Edge fabric
FID 20
E