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Central Management System
Router
A communications device connected between 2 (or more) different networks, which maps (routes/
directs) traffic between the IP addresses on each network.
Service
Services comprise 3 elements—a pair of communicating software applications; the definition of the
data structures which the applications exchange; and the definition of the protocols by which the
applications exchange data structures. Established services include FTP, Telnet, HTTP, SMTP, etc. There are
also proprietary or special purpose services.
SMTP
Simple Mail Transfer Protocol. The service for encapsulating and sending messages to another person on
the Internet, known as Email.
SSH
Secure shell. A special program providing a secure communications channel between SSH client and
SSH server processes.
Switch
An Ethernet connectivity device, similar to but more advanced than a Hub, which
partitions traffic between connected computers to lessen congestion.
On an Ethernet LAN a switch determines from the physical device MAC address in each
incoming message frame, to which output port it is forwarded.
TCP/IP
TCP/IP (Transmission Control Protocol/Internet Protocol) is the basic communication language or
protocol of the Internet. It can also be used as a communications protocol in a private network (either an
intranet or an extranet).
Telnet
A service which provides remote terminal login to a multi-user host.
VLAN
VLAN's provide a function for separating users into groups through network segments. This is done
virtually and eliminates the need for physical hardware changes and configurations. This means that
only one switch can be used for creating separate "virtual" LANs on this one physical hardware device.
For instance, on a 24-port switch, you can create 3 isolated VLANs of 8 users each.
VLANs can also span over multiple switches, i.e. 2 users on one switch and 3 users on another using
VLAN Trunking.
VLAN Trunking
More sophisticated devices can mark packets through tagging, so that a single interconnect (trunk) may
be used to transport data for various VLANs.
Grouping computers located in disparate locations by VLAN can simplify a network design. A VLAN is
essentially the same as a local area network (LAN), but it allows for easier grouping of computers even if
they're not on the same network switch.
VLAN memberships are configured through a software interface, as opposed to physically moving cables
on switches. Most enterprise-level networks today use the concept of VLANs.
Without VLANs, a switch considers all interfaces on the switch to be in the same broadcast domain.
