Differences between connected lookup and unconnected lookup ?

Connected Lookup	Unconnected Lookup
This is connected to pipleline and receives the input values from pipleline.	Which is not connected to pipeline and receives input values from the result of a: LKP expression in another transformation via arguments.
We cannot use this lookup more than once in a mapping.	We can use this transformation more than once within the mapping
We can return multiple columns from the same row.	Designate one return port (R), returns one column from each row.
We can configure to use dynamic cache.	We cannot configure to use dynamic cache.
Pass multiple output values to another transformation. Link lookup/output ports to another transformation.	Pass one output value to another transformation. The lookup/output/return port passes the value to the transformation calling: LKP expression.
Use a dynamic or static cache	Use a static cache
Supports user defined default values.	Does not support user defined default values.
Cache includes the lookup source column in the lookup condition and the lookup source columns that are output ports.	Cache includes all lookup/output ports in the lookup condition and the lookup/return port.