3Com Switch 8800 Family IPsec Module Configuration and Command reference Guide

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VPN OVERVIEW
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The content below applies to the IPsec module, so the command views in this
document apply to the module and not the Switch 8800 Family switches.
VPN Overview Along with the increasingly wide application of the Internet, Virtual Private
Network (VPN) emerged to construct private networks on public networks.
"Virtual" here mainly indicates that VPN is a kind of logical networks.
Employees travel around on business more and more frequently; foreign services
and customers are scattered more widely; cooperation is conducted with a
growing number of partners. More and more companies therefore turn to the
Internet for market promotion, sales, after-sales services, and also for conducting
training and other activities. This provides a broad market for the application of
VPN.
Features of VPN ■ Different from a traditional network, VPN does not exist physically. It is a kind
of logical network, a virtual network formed through resources collocation
employing the current public network.
■ Each VPN is only for a particular enterprise or group of users. For VPN users,
VPN is just like any traditional private network. As a kind of private network,
VPN keeps resources independent of the underlying network, meaning
resources of each VPN are normally inaccessible for other VPNs over the
underlying network and users outside this VPN. It also delivers adequate
security, safeguarding the internal information of VPN against external
invasion.
■ VPN is a kind of upper layer service but not simple. It establishes network
interconnection between private network users, including network topology
inside VPN, route calculation, joining and leaving of members, etc. Thus, VPN
technology is much more complicated, compared to common point-to-point
applications alike.
Benefits of VPN VPN allows you to:
■ Establish reliable and safe connection between remote users, oversea agencies,
partners, suppliers and company headquarters, ensuring security of data
transmission. This advantage is of special significance to the amalgamation of
E-business or financial network with communication network.
■ Provide information communication over public networks, thus allowing
enterprises to connect with remote offices, staff traveling on business and
business partners at a low cost, while improving utility of network resources.
This will help Internet Service Providers (ISPs) increase profits.