Section 5
Glossary
5-10
WN825
Subnet Mask
A methodology that determines what the router will examine for
the destination of an IP address. A router delivers packets using
the network address.
Switch
On an Ethernet network, a switch filters frames based on the
MAC address, in a manner similar to a bridge. A switch is more
advanced because it can connect more than two segments.
T
TCP
Transmission Control Protocol on OSI transport layer four,
provides reliable transport over the network for data transmitted
using IP (network layer three). It is an end-to-end protocol
defining rules and procedures for data exchange between hosts
on top of connectionless IP. TCP uses a timer to track
outstanding packets, checks error in incoming packets, and
retransmits packets if requested.
TCP/IP
The Transmission Control Protocol/Internet Protocol suite
provides standards and rules for data communication between
networks on the Internet. It is the worldwide Internetworking
standard and the basic communications protocol of the Internet.
Tunnel
To place packets inside other packets to send over a network.
The protocol of the enclosing packet is understood by each
endpoint, or tunnel interface, where the packet enters and exits
the network. VPNs rely on tunneling to create a secure network.
Tunneling requires the following protocol types:
A carrier protocol, such as TCP, used by the network that the
data travels over
An encapsulating protocol, such as IPSec, L2F, L2TP, or
PPTP, that is wrapped around the original data
A passenger protocol, such as IP, for the original data
U
UDP
User Datagram Protocol. A method used along with the IP to
send data in the form of message units (datagram) between
network devices over a LAN or WAN.
