Cisco Systems EA6500 Manual De Usuario
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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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Chapter 37 Configuring the Switch Fabric Module
Understanding How the Switch Fabric Module Works
Switch Fabric Module Slots
With a WS-C6513 chassis, install the Switch Fabric Modules in either slot 7 or 8.
Note
In a WS-C6513 chassis, only slots 9 through 13 support dual-switch fabric interface switching modules
(for example, WS-X6816-GBIC).
(for example, WS-X6816-GBIC).
With all other chassis, install the Switch Fabric Modules in either slot 5 or 6.
Switch Fabric Redundancy
The Switch Fabric Module first installed functions as the primary module. For redundancy, you can
install a redundant Switch Fabric Module. When two Switch Fabric Modules are installed at the same
time, the module in the upper slot functions as the primary module, and the one in the lower slot
functions as the backup. If you reset the module installed in the upper slot, the one in the lower slot
becomes active.
install a redundant Switch Fabric Module. When two Switch Fabric Modules are installed at the same
time, the module in the upper slot functions as the primary module, and the one in the lower slot
functions as the backup. If you reset the module installed in the upper slot, the one in the lower slot
becomes active.
No configuration is required for Switch Fabric Module redundancy. The module in the upper slot
functions as the primary module and a redundant Switch Fabric Module in the lower slot automatically
takes over if the primary module fails.
functions as the primary module and a redundant Switch Fabric Module in the lower slot automatically
takes over if the primary module fails.
Forwarding Decisions for Layer 3-Switched Traffic
Either a PFC2 or a Distributed Feature Card (DFC) makes the forwarding decision for Layer 3-switched
traffic as follows:
traffic as follows:
•
A PFC2 makes all forwarding decisions for each packet that enters the switch through a module
without a DFC.
without a DFC.
•
A DFC makes all forwarding decisions for each packet that enters the switch on a DFC-enabled
module in these situations:
module in these situations:
–
If the egress port is on the same module as the ingress port, the DFC forwards the packet locally
(the packet never leaves the module).
(the packet never leaves the module).
–
If the egress port is on a different fabric-enabled module, the DFC sends the packet across the
SFM to the egress module, which sends it out the egress port.
SFM to the egress module, which sends it out the egress port.
–
If the egress port is on a different nonfabric-enabled module, the DFC sends the packet across
the SFM to the Supervisor Engine 2. The Supervisor Engine 2 fabric interface transfers the
packet to the 32-Gbps switching bus where it is received by the egress module and is sent out
the egress port.
the SFM to the Supervisor Engine 2. The Supervisor Engine 2 fabric interface transfers the
packet to the 32-Gbps switching bus where it is received by the egress module and is sent out
the egress port.
Switching Modes
When you install a Switch Fabric Module, the traffic is forwarded to and from modules in one of the
following modes:
following modes:
•
Compact mode—The switch uses this mode for all traffic when only fabric-enabled modules are
installed. In this mode, a compact version of the DBus header is forwarded over the switch fabric
channel, which provides the best possible performance.
installed. In this mode, a compact version of the DBus header is forwarded over the switch fabric
channel, which provides the best possible performance.