SSIS Variables vs Parameters (SSIS Denali)

Question

1. What is the difference between Variables and Parameters in SSIS Denali?
2. If there is any difference then What is that which Variables cannot do that Parameter

Answer 1

Parameters are using send data from outside of the package like usernames, passwords or connectionstrings etc. Variables are using inside of the package. It means you can define a variable in one of your SSIS package and use it in package level.