Definitions for teachers by teachers

VPN Connection

by Sarah Barnett

VPN stands for Virtual Private Network, the concept of using the internet or other 'public' carriers as transit for private network traffic, usually in encrypted form. The use of encryption in the lower protocol layers to provide a secure connection through an otherwise insecure network, typically the Internet. VPNs are generally cheaper than real private networks using private lines but rely on having the same encryption system at both ends. The encryption may be performed by firewall software or possibly by routers.

Link-level (layer 2 and 3) encryption provides extra protection by encrypting all of each datagram except the link-level information. This prevents a listener from obtaining information about network structure. While link-level encryption prevents traffic analysis (a form of attack), it must crypt/decrypt on every hop and every path.

Protocol-level encryption (layer 3 and 4) encryption encrypts protocol data but leaves protocol and link headers clear. While protocol-level encryption requires you to encrypt/decrypt data only once, and it encrypts/decrypts only those sessions that need it, headers are sent as clear text, allowing traffic analysis.

Application (layer 5 up) encryption is based on a particular application and requires that the application be modified to incorporate encryption.

Necessary? No
This is a term that I have never heard before.  I am always glad to learn new things and will file this away for future reference, but a VPN Network is not something I need to be concerned with now.

by Zan Brixey

VPN Network (v p n net' wurk): VPN Network is short for Virtual Private Network and is a private network that is constructed using public wires to connect nodes (processing locations). The Internet is used as the medium for transporting data but security mechanisms ensure that only authorized users can access the network. Access is controlled; data is encrypted, secure and cannot be intercepted. Thus, a private network is configured within a public network. This is quite economical as VPNs take advantage of the economics of scale and built-in management facilities of large public networks. These networks appear as private national or international networks to the customer, but physically share the backbone trunks with other customers.

For a comprehensive list of links to various sites, see those listed by Webopedia.

by Becky Trieger

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