Virtual Private Network

Virtual Private Network

A Layer 2 MPLS VPN is a term in computer networking. It is a method that Internet service providers use to segregate their network for their customers, to allow them to transmit data over an IP network.

A VoIP VPN combines voice over IP and virtual private network technologies to offer a method for delivering secure voice. Because VoIP transmits digitized voice as a stream of data, the VoIP VPN solution accomplishes voice encryption quite simply, applying standard data-encryption mechanisms inherently available in the collection of protocols used to implement a VPN.

Virtual Private Data Network

A virtual private network (VPN) extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. The benefits of a VPN include increases in functionality, security, and management of the private network.

<networking, security> (VPN) 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 encrypt/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. {Cisco (http://cisco.com/univercd/cc/td/doc/product/lan/cat5000/cnfg_nts/rsm/rsm_pa/4801encr.htm)}. (1999-11-15)

A mediated VPN is a virtual private network topology where two or more participants connect to a central switchboard server managed typically by a third party in order to create a virtual private network between them, as distinct from a typical VPN arrangement whereby clients of an organisation connect to a VPN concentrator managed by the same organization.

VPN blocking is a technique used to block the encrypted protocol tunneling communications methods used by virtual private network (VPN) systems. Often used by large organizations such as national governments or corporations, it can act as a tool for computer security or Internet censorship by preventing the use of VPNs to bypass network firewall systems.