Sourcefire is expected to be acquired by Cisco or a competitor. All network security functions will collapse to the switch, something Richard Stiennon called Secure Network Fabric. At the most I see a “switch plus one” model, where no more than one stand-alone security device will support the core switch/router infrastructure. At some point a majority of hosts will be virtualized, and many network and host security measures will be performed by the hypervisor anyway. Everything that a switch can’t perform, security-wise, will be expected of the “firewall””]
Source: https://taosecurity.blogspot.com/2006/10/thoughts-on-sourcefire-ipo.html