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| 4.1 |  | Methods of Inter-VLAN Routing |
| 4.1.8 |  | Cisco Layer 3 feature cards |

Although the performance of route switch processors is generally adequate for typical applications, there are circumstances where additional performance is required. Situations that may require additional routing performance include the following:

- A high proportion of traffic needs to cross VLAN boundaries.
- A large number of interfaces are present and many are Gigabit or greater in speed.
- Additional switching capacity has been provided through the addition of a Switch Fabric Module.

Two layer 3 feature cards available for the Catalyst 6000 series of switches are the Multilayer Switch Feature Card (MSFC) and the Policy Feature Card (PFC).

The Multilayer Switch Feature Card (MSFC) provides layer 3 functionality and enables the use of Cisco Express Forwarding for increased routing performance.

The Policy Feature Card (PFC) contains all the Application-Specific Integrated Circuits (ASICs) for Layer 2 and 3 look-ups and performs many Cisco IOSŪ features in hardware. It performs IP Unicast and Multicast forwarding, QoS, and Access Control List (ACL) lookups in hardware. The PFC scales central forwarding to 30 Mbps.