Hi,

The packet forwarding/switching is done using one of the following method:

1- Process Switching

2- Fast Switching

3- CEF Switching

4- ASIC (Application Specific Integrated Circuit).

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1- With (Process Switching), the packets are forwarded to the CPU and the CPU performs Switching , its often called Software Switching as the Switching is done on software basis.

2- With (Fast Switching), a Fast Switching table is created on a router On demand.

3- With (CEF Switching), the RIP table is copied into the CEF FIB once the router starts up, CEF Swirching is a topology driven.

CEF Switching has two tables:

a- The Adjacency table

b- The FOrward Information Base Table.

CEF Loadbalancing:

CEF performs Load balancing in two ways:

a- CEF load Balancing Per destination/prefix

b- CEF load balancing per packet

The default CEF loadbalancing Scheme is (Per Destination), However, Per packet load balancing is not recommended because

packet might arive at destination out of order.

4- With (ASIC) Application Specific Integrated Circuit, the hardware is correctly programmed to handle the packet switching.

Here is Some characterstics about IP Switching methods:

http://www.cisco.com/en/US/tech/tk827/tk831/technologies_white_paper09186a00800a62d9.shtml#fast

HTH

Mohamed