Dvpn Overview; Basic Concepts Of Dvpn - 3Com MSR 50 Series Configuration Manual

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DVPN Overview

Basic Concepts of DVPN

DVPN C
ONFIGURATION
When configuring DVPN, go to these sections for information you are interested
in:
"DVPN Overview" on page 1557
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"DVPN Configuration Task List" on page 1562
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"Displaying and Maintaining DVPN" on page 1571
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"DVPN Configuration Example" on page 1571
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The demands of enterprises for setting up virtual private networks (VPNs) across
the public network are growing. The demands are hardly to satisfy with traditional
VPN approaches however, as most enterprise branches access the public network
with dynamic addresses, which tend to change.
Dynamic virtual private network (DVPN) can address the issue well.
In DVPN, a collection of nodes connected to the public network is regarded as a
non-broadcast multi-access (NBMA) network, the public network as the link layer
of this NBMA network, and tunnels being the virtual paths between subnets of
intranet as the network layer. Branch devices dynamically access the public
network.
VPN address management (VAM) is a major protocol used in the DVPN solution. It
collects, maintains, and distributes dynamic information to help set up internal
secured tunnel conveniently. When forwarding a packet for a subnet, the device
first obtains its next hop on the private network through a routing protocol and
the public network address associated with this next hop; then encapsulates the
packet with the public address as the destination address of the tunnel; and finally
sends the packet down the tunnel to the destination.
The following key roles are involved in DVPN:
DVPN client
A DVPN client is a device at either end of a DVPN tunnel. It can be a networking
device or a host. A DVPN client takes part in tunnel setup and must implement the
VAM client feature.
VAM server
A VAM server receives registration information from DVPN clients and manages
and maintains information about DVPN clients. Currently, a VAM server is usually a
high performance routing device with the VAM server feature enabled.