ng a letter addressed to a non-local company in a larger packet of information, and sending this on to another postal location. When the packet arrives at the next location, the letter is extracted from the packet and routed to the intended final destination.
The Internet provides the user wide area network (WAN) communications more cheaply than the alternatives of leased line, frame relay, or asynchronous transfer mode (ATM). What is at issue, however, is the ability of the Internet to provide the necessary security, bandwidth and service quality characteristic of that obtained via private networking.
Internet service providers (ISPs), equipment vendors, and the developers of associated software tout the ability of virtual private networks (VPNs) or extranets, to provide the security, quality of service, availability, and multi-protocol support associated with private networks. While connection to business partners and customers is of concern, VPNs may address locations where the traditional private network connection is not justified. Regardless, VPNs do raise some significant questions when they are considered as alternatives for existing private networks. These include: dealing with the issue of quality of service; handling of non-IP traffic; authentication and assignment of IP addresses; and overall level of security [3].
The remote user (or network) accessing the VPN needs to connect to an Internet Service Provider (ISP) Point of Presence (POP) via modem, DSL, or cable modem. Generally speaking, software located on the end user computer encrypts and packages the data such that it can theoretically be securely transmitted to the ISP. The ISP is then able to send the packet off on the Internet like any other regular packet of information. Encryption and authentication protocols provide enough information to get the information to its destination while maintaining control over access to its contents. In this man...