it is nothing but system level testing

If there is no suffecient time to do all planed testing 
activities. then we can do testing on major functionality 
of the product. this could be achieved by AD-HOC testing
this is said tobe bottle neck testing.

this is not a registered name.
this is related to perfo. testing.
bottle necks are the point in a s/w developmenet cycle when 
the s/w surges in its perfo.

Bottleneck Testing is system testing and is related to
performance testing, in which sub-systems are checked for
sake of performance.

**this is all i know about**