A post appeared on the SSIS forum today in which the poster was getting slightly confused about the use of SSIS Connection Managers and how they differ from DTS Connections so I thought it would be a good idea to illustrate the differences here to hopefully save anyone else from having the same headaches.
A problem with DTS Connections was that if all your tasks used the same Connection object then everything happened agains the same physical connection. Not a good situation as operations against the connection object effectively get queued up. This problem is alluded to at the bottom of this article.
This is not the case with SSIS Connection Managers. Instead, Connection Managers maintain a pool of connections. Each task that utilises the Connection Manager will get its own connection to the data source.
Note that if you want to you can make SSIS Connection Managers behave like DTS Connections by setting RetainSameConnection=TRUE. There is actually a use for this as exhibited here: http://blogs.conchango.com/jamiethomson/archive/2005/08/20/2048.aspx
-Jamie