Corporate Headquarters

•
Overview of Business Scenarios, page 2-1
•
Assumptions, page 2-2
•
Cisco SAFE Blueprint, page 2-3
•
Hybrid Network Environments, page 2-4
•
Integrated versus Overlay Design, page 2-4
•
Network Traffic Considerations, page 2-5
•
Network Resiliency, page 2-10
•
VPN Performance Optimization Considerations, page 2-12
•
Network Management Considerations, page 2-16
Note
In this Guide, the term ‘Cisco 7200 series router’ implies that an Integrated Service Adaptor (ISA) or a 
VAM (VAM, VAM2, or VAM2+) is installed in the Cisco 7200 series router.
Overview of Business Scenarios
The site-to-site and extranet scenarios explained in this guide provide a remote office and a business 
partner access to a corporate headquarters network through Generic Routing Encapsulation (GRE) or IP 
Security Protocol (IPSec) tunnels. The remote access scenario provides a remote user access to a 
corporate headquarters network through secure IPSec, Point-to-Point Tunneling Protocol (PPTP), or 
Layer 2 Tunnel Protocol (L2TP) tunnels. (See 
Figure 2-1
.)
Note
For detailed information on configuring network access server (NAS)-initiated access VPNs using the 
Layer 2 Forwarding (L2F) tunneling protocol, refer to the 
Access VPN Solutions Using Tunneling 
Technology
publication.

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2-2
Cisco IOS VPN Configuration Guide
OL-8336-01
Chapter 2 Network Design Considerations
Assumptions
In each scenario, a tunnel is constructed, encryption is applied on the tunnel, and different traffic types 
(for example, IP, User Datagram Protocol [UDP], and Transmission Control Protocol [TCP]) are either 
permitted or denied access to the tunnel. This controls the level of access the remote office and business 
partner have to the corporate intranet and secures the data exchanged between the sites.