For further details on this architecture, consult these documents:
"SAFE: A Security Blueprint for Enterprise Networks"
http://www.cisco.com/en/US/netsol/ns340/ns394/ns171/ns128/networking_solutions_white_paper09186a008009c8b6.l
"SAFE: Extending the Security Blueprint to Small, Midsize, and Remote-User Networks"
http://www.cisco.com/en/US/netsol/ns340/ns394/ns171/ns128/networking_solutions_white_paper09186a008009c8a0.l
"SAFE: VPN IPSec Virtual Private Networks in Depth"
http://www.cisco.com/application/pdf/en/us/guest/netsol/ns128/c654/cdccont_0900aecd800b05ad.pdf
"Cisco SAFE: Wireless LAN Security in Depth"
http://www.cisco.com/en/US/netsol/ns340/ns394/ns171/ns128/networking_solutions_white_paper09186a008009c8b3.l
"SAFE: IP Telephony Security in Depth"
http://www.cisco.com/en/US/netsol/ns340/ns394/ns171/ns128/networking_solutions_white_paper09186a00801b7a50.l
"SAFE: IDS Deployment, Tuning, and Logging in Depth"
http://www.cisco.com/en/US/netsol/ns340/ns394/ns171/ns128/networking_solutions_white_paper09186a00801bc111.l