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Differences between process and fast switching

Hi ,

Kindly clarify me the differences between prcess and fast switching .Whether the fast and CEF are same.....?

Thanks in advance

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Differences between process and fast switching

Cisco Employee

Differences between process and fast switching

Hello Tamil,

Please find below the differences between Process and CEF switching,

Process Switching:


In process switching the first packet is copied to the system buffer. The router looks up the Layer 3 network address in the routing table and initializes the fast-switch cache. The frame is rewritten with the destination address and sent to the outgoing interface that services that destination. Subsequent packets for that destination are sent by the same switching path. The route processor computes the cyclical redundancy check (CRC).

Fast Switching:

When packets are fast switched, the first packet is copied to packet memory and the destination network or host is found in the fast-switching cache. The frame is rewritten and sent to the outgoing interface that services the destination. Subsequent packets for the same destination use the same switching path. The interface processor computes the CRC.

Source:

http://www.cisco.com/en/US/docs/ios/12_2/switch/configuration/guide/xcfovips.html

You can also go through the Inside Cisco IOS architechture book to get a detailed view on the same.

Thanks,

Ricky Micky

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