Well I think it comes from the ethos, of let a router be a router, let a switch be a switch.
Back in the day - if you wanted VPN's you had a concentrator, but then I suspect Cisco started to listen to it's customers. Then VPN's and Firewalls are in the IOS of routers, dynamic routing is coded into Firewalls. Firewalls/Routers performing IPS/IDS/SPAM/SSL etc
I think it's a system of consolodation, one device does all.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...