Operation Manual

72 NetWAYS/ISDN – Glossary
SPX (Sequenced Packet Exchange)
A protocol that enables two workstations or applications to
communicate over a network. SPX uses the NetWare protocol
IPX for addressing. SPX uses NetWare IPX to transmit data,
but controls the receipt and the order of messages in the
packet stream.
TCP (Transmission Control Protocol)
TCP is a connection-oriented protocol for use over packet-ori-
ented networks. TCP builds directly on the Internet Protocol
(IP) and provides virtual connection services for assured, se-
quenced transport of user data. TCP provides a reliable con-
nection between two systems. TCP is specified in RFC 793.
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 pack-
ets of the transported protocol are encapsulated for trans-
port in those of the second protocol. At the other end of the
tunnel, the encapsulated packets are extracted again.
(VPN) Virtual Private Network
International name for secure logical networks based on vir-
tual connections.
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 packets of a given protocol are transparently transported
in those of another protocol.
X.75
X.75 is a transfer protocol with a transfer speed of 64 kbits/s.
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