Friday, June 5, 2009

Vpn services

vpn services is very important and also admin responsibility secure his network. computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger networks as opposed to running across a single private network. The Link Layer protocols of the virtual network are said to be tunneled through the transport network. but a VPN does not need to have explicit security features such as authentication or content encryption. when we use vpn services that time some service work wich was secure our data because when we send or recive data that time in encripted form hacker can't read easily our data.

Routing:
Tunneling protocols can be used in a point-to-point topology that would generally not be considered a VPN, because a VPN is expected to support arbitrary and changing sets of network nodes. Since most router implementations support software-defined tunnel interface, customer-provisioned VPNs often comprise simply a set of tunnels over which conventional routing protocols run. PPVPNs, however, need to support the coexistence of multiple VPNs, hidden from one another, but operated by the same service provider.

Building blocks:
Depending on whether the PPVPN runs in layer 2 or layer 3, the building blocks described below may be L2 only, L3 only, or combinations of the two. Multiprotocol Label Switching (MPLS) functionality blurs the L2-L3 identity..

Layer 1 services:
Virtual private wire and private line services In both of these services, the provider does not offer a full routed or bridged network, but components from which the customer can build customer-administered networks. VPWS are point-to-point while VPLS can be point-to-multipoint. They can be Layer 1 emulated circuits with no data link structure. An unfortunate acronym confusion can occur between Virtual Private Line Service and Virtual Private LAN Service; the context should make it clear whether "VPLS" means the layer 1 virtual private line or the layer 2 virtual private LAN.

Layer 2 services:
Layer 2 that allows for the coexistence of multiple LAN broadcast domains, interconnected via trunks using the IEEE 802.1Q trunking protocol.because it is secure compare to another. Other trunking protocols have been used but have become obsolete, including Inter-Switch Link .

Virtual private LAN service
VLANs allow multiple tagged LANs to share common trunking. The former is a layer 1 technology that supports emulation of both point-to-point and point-to-multi point topologies. The method discussed here extends Layer 2 technologies such as 802.1d and 802.1q LAN trunking to run over transports.

A VPLS is a Layer 2 PPVPN, rather than a private line, emulating the full functionality of a traditional local area network. From a user standpoint, a VPLS makes it possible to interconnect several LAN segments over a packet-switched, or optical, provider core. making the remote LAN segments behave as one single LAN. user could be access.


Source: http://en.wikipedia.org/wiki/Virtual_private_network#Virtual_private_LAN_service_.28VPLS.29

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