For multi-point connections, such as an X.25 or other packet-switched private networks, one subnet is sufficient for all connections.
An IP address for each connection or virtual circuit is required in the multi-point connection.
A packet assembler-disassembler (PAD)
is used on X.25 networks to connect computers to the X.25 network Cloud as shown below.
The X.25 Cloud is a world-wide private network that consists of a bunch of network devices that separate PADs.
To connect to a VPN client, each VPN server requires a public address. This address becomes one end of the communications tunnel. The VPN client receives an address from the VPN server either via DHCP or from a static address pool configured on the VPN server. When communicating over the VPN connection, the VPN client uses the address assigned by the DHCP Server for the VPN interface to access intranetwork resources. Any IP addressing design must account for the public address and the range of private network addresses required by the VPN server design. A private network address is required for each VPN client that simultaneously accesses the intranetwork.
The next lesson examines QoS.