Process Switching vs Fast Switching

[shiraforkosh1]

Hi

I read about the Process Switching and Fast Switching in the Cisco documents, and the explanation about the two subject is the same. The only different that I saw there was that in the process switching paragraph was written that the first packet is saved in the system buffer, and in Fast Switching  paragraph  was written that the first packet is saved in the packet memory. Does packet memory is an actually different memory component then system buffer, Or it just an other way to describe it? If the answers for this question is that it is the same thing, so what is the different between the Process Switching and Fast Switching?

link for the Cisco documents:

http://www.cisco.com/c/en/us/td/docs/ios/12_2/switch/configuration/guide/fswtch_c/xcfovips.html

[Mark Malone]

Hi

process switching was the original switching method , fast switching came then with the ability to use a cache to take the load off the processor

This doc explains the methods better

http://resources.intenseschool.com/packet-switching-methods-process-switching-fast-switching-and-cef/

[Arush Bhardwaj]

Good evening friend,

Would like to add few more points on Process Switching and Fast Switching -

In case of Process switching inspection of every packet is done by the processor. Infact SNMP traps from the router and telnet packets destined for the router are always process-switched.Process routing task is more processor intensive, complex, and introduces a longer latency. To address these concerns ,Fast Switching was introduced.

In Fast Switching, the first packet to a destination is process switched but subsequent packets are forwarded using the information stored in the fast cache.

Below link shared the comparison between Process Switching and Fast Switching in form a table -

http://www.ipwithease.com/process-switching-vs-fast-switching/

[Joseph W. Doherty]

Oh, just wanted to also note, on many Cisco software based routers, there's a considerable performance capacity difference between process and fast switching.  I've attached an old router performance white paper where you can see the documented performance differences.