For your remote site, 1700 VPN routers will be very good choice depending the traffic load. If only several users per site, 800 routers will be cool.
Central site 3600, 7100 or 7200 routers depending the VPN traffic load as well. You only need one internet physical connection (serail port , ATM or FastEthernet depending on your link). Then you can build up 27 logical GRE tunnels with IPSEC to 27 remote sites.
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...