In distributed switching, the switching process occurs on Versatile Interface Processor (VIP) and other interface cards that support switching. When distributed Cisco Express Forwarding is enabled, line cards, such as VIP line cards or GSR line cards, maintain an identical copy of the FIB and adjacency tables. The line cards perform the express forwarding between port adapters, relieving the RSP of involvement in the switching operation. distributed Cisco Express Forwarding uses an Inter Process Communication (IPC) mechanism to ensure synchronization of FIBs and adjacency tables on the RP and line cards.
For model numbers and hardware compatibility information, see the
Catalog. For information on configuring distributed Cisco Express Forwarding, see the Cisco Express Forwarding Overview module.
For information on configuring Multicast Distributed Switching (MDS), see the Configuring Multicast Distributed Switching module.
The following figure illustrates the distributed switching process on the device:
Figure 5. Distributed Switching
The VIP card installed on this device maintains a copy of the routing cache information needed to forward packets. Because the VIP card has the routing information it needs, it performs the switching locally, making the packet forwarding much faster. Device throughput is increased linearly based on the number of VIP cards installed on the device.