User guide

Glossary
Multi-Tech Systems, Inc. RF550VPN User Guide 74
S
Server
A provider of resources (e.g.,file servers and name servers). For example, your RouteFinder provides
Internet access and is, therefore, an Internet Access Server.
Static Routing
Involves the selection of a route for data traffic on the basis of routing options preset by the network
administrator.
Subnet
A portion of a network that shares a common address component. On TCP/IP networks, subnets are all
devices whose IP Addresses have the same prefix. For example, all devices with IP addresses starting
with 213.0.0 are part of the same subnet.
SubnetMask /IPAddressMask
Subnet mask is what is used to determine what subnet an IP address belongs to. Subnetting enables
the network administrator to further divide the host part of the address into two or more subnets.
T
TCP/IP (Transmission Control Protocol/Internet Protocol)
A suite of communication protocols used to connect hosts on the Internet. Every computer that wants
to communicate with another computer on the Internet must use the TCP/IP protocol to transmit and
route data packets. The format of an IP address is a 32-bit numeric address written as four octets
separated by periods. Each number can be zero to 255. Within an isolated network, you can assign IP
addresses at random as long as each one is unique. However, connecting a private network to the
Internet requires using registered IP addresses to avoid duplication.
The four groups of numbers (octets) are used to identify a particular network and host on that network.
The InterNIC assigns Internet addresses as Class A, Class B, or Class C. Class A supports 16 million
hosts on each of 127 networks. Class B supports 65,000 hosts on each of 16,000 networks. Class C
supports 254 hosts on each of 2 million networks. Due to the large increase in access to the Internet,
new classless schemes are gradually replacing the system based on classes.
Triple DES (3DES)
Cipher that applies the DES cipher three times with either two or three different DES keys.
Tunneling
As an Internet term, tunneling means to provide a secure temporary path over the Internet or other IP-
based network in a VPN (Virtual Private Network) scenario. In this context, tunneling is the process of
encapsulating an encrypted data packet in an IP packet for secure transmission across an inherently
insecure IP network, such as the Internet.
U
UDP (User Datagram Protocol)
An Internet Standard transport layer protocol. It is a connectionless protocol that adds a level of
reliability and multiplexing to IP.
V
Virtual Private Network
A private network built atop a public network. Hosts within the private network use encryption to talk to
other hosts; the encryption excludes hosts from outside the private network even if they are on the
public network.
W
WAN (Wide Area Network)
A network that connects host computers and sites across a wide geographical area.