An ISR (x800 series) combines a router, VPN device and Firewall with the modularity to turn on one or all features AND the processing power to handle it. That firewall in an ISR combined with CBAC properly configured is all the security you need. Now Combine that with a properly built ACL and you have a hardened router and firewall in one device.
ACLs tend to slow down traffic but can be the very last (or first as the case may be) line of defense.
Wires and fires has become wireless and tireless.
