Page 25 - M. Abrahim Thesis

Computer Network 2021

Figure 2-5 shown an Intranets and Extranets Hierarchy

https://www.youtube.com/watch?v=4_zSIXb7tLQ&t=30s

https://www.youtube.com/watch?v=HEzN3B_aXE4&t=26s

2.5 Virtual Private Networks
A virtual private network (VPN) is a private network that is constructed within a public
network infrastructure such as the global Internet. For example, using a VPN, a telecommuter
can access the company headquarters’ network through the Internet by building a secure tunnel
between the telecommuter’s PC and a VPN router in the headquarters. Cisco products support
the latest in VPN technology. A VPN is a service that offers secure, reliable connectivity over a
shared public network infrastructure such as the Internet. VPNs maintain the same security and
management policies as a private network. They are the most cost-effective method of
establishing a point-to-point connection between remote users and an enterprise customer’s
network.

Three main types of VPNs exist, as shown in Figure 2-6:

• Access VPNs provide remote access for a mobile worker and small office/home
office (SOHO) to the headquarters’ intranet or extranet over a shared
infrastructure. Access VPNs use analog dialup, ISDN, DSL, mobile IP, and cable
technologies to securely connect mobile users, telecommuters, and branch
offices.
• Intranet VPNs link regional and remote offices to the headquarters’ internal
network over a shared infrastructure using dedicated connections. Intranet VPNs
differ from extranet VPNs in that they allow access only to the enterprise
customer’s employees.
• Extranet VPNs link business partners to the headquarters’ network over a shared
infrastructure using dedicated connections. Extranet VPNs differ from intranet
VPNs in that they allow access to users outside the enterprise.

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