Specifications

138 AVM Access Server – Glossary
TCP/IP address: see “IP address” on page 127
Tunneling
Tunneling is a technique in which the packets of a given protocol are
transparently transported in those of another protocol. The resulting
transparent connection between the endpoints of the transport is
called a tunnel. The data packets of the transported protocol are en-
capsulated for transport in those of the second protocol. At the other
end of the tunnel, the encapsulated packets are extracted again.
VPN (Virtual Private Network)
Generic name for secure logical networks based on virtual connec-
tions.
A virtual private network is a wide-area network accessible only to
members of a given company or organization, but transported over the
existing infrastructure of a publicly available network.
Virtual private networks use tunneling, a technique in which the pack-
ets of a given protocol transparently transported in those of another
protocol. See also “Tunneling” on page 138.
UDP (User Datagram Protocol)
This protocol, situated in Layer 4 (the Transport Layer) of the OSI refer-
ence model, provides applications with a transaction-oriented packet
transport service. UDP includes only minimal protocol mechanisms for
communication between systems. Unlike TCP, UDP does not provide
end-to-end transmission monitoring: the sender has no assurance that
the addressee has received a given packet, nor is the sequence of
packets preserved. UDP is defined in RFC 768.