Structure Of Vpn Network; Fundamental Technology Of Vpn - 3Com 3C13636 Configuration Manual

3Com Router 3000 Ethernet Family
Configuration Guide
business partners at a low cost, while improving utility of network resources. This
will help Internet Service Providers (ISPs) increase profits.
Add or delete users through software configuration rather than changing hardware
facilities, thus delivering great flexibility.
Support mobile access of VPN users at any time in any place, thus meeting
growing mobile service demands.
Create VPN with QoS (e.g. MPLS VPN), providing differentiated services for VPN
users and by pricing these services differently obtaining more profits. For the
fundamentals and related introduction of MPLS VPN, refer to the chapter "MPLS
Configuration".

1.1.3 Structure of VPN Network

VPN comprises a group of sites. A site might join one or more VPNs, but any two sites
are IP reachable only if they belong to the same VPN. According to its standard
definition, VPN with all its Sites coming from a single enterprise is called Intranet, and
cross-enterprise VPN is by contrast called Extranet.
VPN 1
Figure 1-1 The composition of VPN
The above chart demonstrates the relationship between five sites and three VPNs.
VPN1---Site2, Site4
VPN2---Site1, Site3, Site4
VPN3---Site1, Site5

1.2 Fundamental Technology of VPN

I. Basic Networking Application of VPN
Take an enterprise as an example. Its intranet through VPN is shown in following figure.
Site 2
Site 4
3Com Corporation
Site 1
VPN 3
Site 3
VPN 2
1-2
Chapter 1 VPN Overview
Site 5