Content

| 9.3 |  | Network Analysis Modules and Switch Fabric Modules |
| 9.3.6 |  | Increasing switching fabric in 6500 series switches |

The Catalyst 6500 Series switch fabric module (SFM), in combination with the Supervisor Engine 2, delivers an increase in available system bandwidth from the default 32Gbps on the forwarding bus to 256 Gbps. Inclusion of a SFM in a 6500 chassis increases the speed that switching, routing and network monitoring modules can transfer data between each other. The SFM reduces latency and the incidence of packet drop due to bandwidth bottlenecks at traffic aggregation points within the network.

The Switch Fabric Module creates a dedicated connection between fabric-enabled modules and provides uninterrupted transmission of frames between these modules. The Switch Fabric Module also provides fabric-enabled modules with a direct connection to the Catalyst 6500 32-Gbps forwarding bus. If two SFMs are installed in the chassis, the secondary module will act as a backup in the event of failure of the first module.

The Switch Fabric Module does not have a console. A two-line LCD display on the front panel shows fabric utilization, software revision, and basic system information.

The following are the key features of the Switch Fabric Module:

- The Switch Fabric Module enables 30 Mpps Cisco Express Forwarding (CEF)-based central forwarding on Supervisor Engine 2.
- The Switch Fabric Module enables up to 210 Mpps distributed forwarding on DCF-enabled switch fabric modules.
- The Switch Fabric Module supports advanced services such as quality of service (QoS) and security in hardware through access control lists (ACLs).

When a SFM is installed, the traffic is forwarded to and from modules in one of these modes:

- Bus mode – Data passes between the local bus and the supervisor engine bus. This mode is used for traffic to or from non-fabric enabled modules and between fabric- enabled and non-fabric-enabled modules.
- Truncated mode – Only the truncated data (the first 64 bytes of the frame) is sent over the switch fabric channel if both the destination and the source are fabric-enabled modules. If either the source or destination is not a fabric-enabled module, the data goes through the switch fabric channel and the data bus. The SWF does not get involved when traffic is forwarded between non-fabric enabled modules.
- Compact mode – A compact version of the DBus header is forwarded over the switch fabric channel, delivering the best possible switching rate. Non-fabric enabled modules do not support the compact mode and generate cyclic redundancy check (CRC) errors if they receive frames in compact mode. This mode is used only when no non-fabric enabled modules are installed in the chassis.

| Interactive Media Activity Drag and Drop: The Mode Type Used to Forward Traffic Internally on a Catalyst 6500 with SFM After completing this activity, the students will be able to understand the mode type on a Catalyst 6500 with SFM.