Hi!
I would really recommend you get the Inside Cisco IOS architecture book,
it
gives a lot of information on the different switching modes of cisco...
In resume, CEF builds the "switching table" in configuration time (instead
on
the first packet of a flow, as fast-switching does). To hold the switching
information
it uses a "mtrie" instead of a mtree, which allows to reference external
tables
instead of pointing to the destinations in the mtree structure (as
fs,distributed sw do) This external tables are updated every time new
information is adquired (for
example, a arp resolution, or cache time out) so the amount of information
that
needs to be changed overtime is a lot less than in other switching modes.
In previous modes, it was necessary sometimes to invalidate the complete
cache in some cases,
now only specific entries are changed.
It was designed to support very big caches (it was tested on backbone
routers),
so it should be quite ok for most applications. Just take care if you
enable it in a
working router, because probably you will need to restart it to get it
working
stable again (I did test on a 3640 + ipsec +12.1.3, and it needed a
restart).
Other difference is that the switching is done per source and destination
and not per destination (as Fsw) so the loadbalancing of packets over
parallel links is better.
Regards.
Bal Sandhu escribió:
> Guys,
>
> does anyone have any information on CEF ?
> How can I measure the improvements upon its implementation ?
>
> cheers,
>
> Bal Sandhu
>
> e-mail : mailto:[EMAIL PROTECTED]
> http://www.madge.com
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