What are the differences between and IPS and IDS?

["Chhabria, Kavita - Apogent" <kchhabria () apogent com>]

Hello all:
 
I would like to understand the differences between IDS and IPS.  We are
planning on installing snort and snortcenter and ACID, however, I have very
limited knowledge of what and IPS is, so I would like to understand it in
depth, more importantly, understand the diff bet IPS and IDS so that I am
sure that we are making 
the right decision to go with an IDS as opposed to an IPS.
 
Please provide me with the differences and advantages and disadvantages of
each approach?
 
Thanks a lot,
 
Kavita Chhabria
Systems Developer
Apogent Technologies
(269) 544-7515
 <mailto:kchhabria () apogent com> kchhabria () apogent com