In my experience Cisco leaves acquisition alone for at least couple of years providing its brand and sales force. If the acquisition isn't proving its worth and/or if revenue growth is staying flat then start packing your bags.

On the other hand I don't like how the acquisition's leadership gets to absorb other BU's which are targeting similar market space because there is a lot of time and effort that gets invested into integrating teams working culture and style. Also the incoming teams fight to keep their product portfolios alive which leads to sub-optimal decisions.