virtual private network (VPN)

The term virtual private network (VPN) is used in several senses. Generally speaking, a virtual private network is one in which customer-specific logical subnetworks are formed within a public network. These can be voice communication networks, the Internet, Frame Relay or ATM, but also access networks with DSL technologies. The interpretation commonly used today for virtual private networks (VPNs) is IP VPNs, in which the participants are connected to each other viatunneling. In general, a virtual private network (VPN) is a closed, logical network that is based on different layers of the OSI reference model and is established for a specific user group. VPN networks are usually based on layers 2 or 3 of the OSI reference model and use tunneling mechanisms for IP traffic. A VPN always uses the publicly accessible transmission networks, where the connections are provided by a public carrier. The user practically forms his private network through these transmission paths. It has security mechanisms, such as identification and authentication of the network participants, so that unauthorized persons cannot gain access to the virtual private network. The services are provided over a public network, which means that the user can also use the carrier's resources. Mobile VPN connection to an IP-enabled corporate network A VPN has the advantages over true private networks, such as a corporate network, of much greater flexibility and performance. For example, users can define their bandwidth requirements or configure bandwidth requirements dynamically (bandwidth on demand). Network-relevant features, such as custom addressing, network management, dynamic configuration and route optimization, can be performed by both the carrier and the user, depending on the carrier. If mobile devices are integrated in a VPN, this is also referred to as mobile virtual private networks, mobile VPNs. A high level of security is achieved through the use of VPN protocols. There are various VPN protocols to protect and encrypt users and company data. These include IP Security Protocol(IPsec), Secure Socket Layer(SSL) and Transport Layer Security(TLS), Point to Point Tunneling Protocol(PPTP), Layer 2 Tunneling Protocol(L2TP) and OpenVPN. IP-based VPNs The communication basis of IP-based VPNs is the Point to Point Protocol(PPP) with IP tunneling. Remote offices can be connected either via dial-up access in fixed networks, but also via mobile networks and, in the case of large data volumes, via leased lines. In this context, we speak of remote access VPNs, via which home workstations and mobile data terminals can access the corporate network. The clients of such a virtual network establish a connection to the access router via the PPP protocol and are authenticated using the Challenge Handshake Authentication Protocol(CHAP). Transmission then takes place via the IP tunnel. Ethernet applications in VPNs The IETF is concerned with the topic of Ethernet and VPNs. It breaks down its activities in terms of IP traffic(layer 3), Ethernet (layer 2) and the SDHhierarchy, and asynchronous transfer mode (ATM) at layer 1. Ethernet services in VPNs according to IETF According to this, a Layer 3 VPN is a VPN set up by the network operator that uses routing

Englisch:	virtual private network - VPN
Updated at:	29.08.2019
#Words:	508
Links:	virtual, network, communication (COM), Internet, asynchronous transfer mode (ATM)
Translations:	DE
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