A network is a collection of computers, server devices, and
communication devices connected together and capable of communication
with one another through a transmission medium.
An internet is any grouping of two or more networks connected
by one or more internet routers.
Network services are the capabilities that the network system
delivers to users, such as print servers, file servers, and
Transmitting information in a network system is made possible
by an addressing scheme that identifies the sender and destination
of the transmission, using network and node addresses. Data
is transmitted toand from these addresses in the form of packets.
A routing table is maintained in each router. This table lists
all networks and routers in the internet and enables routers
to determine the most efficient route for each packet. The routing
table serves as a logical map of
the internet, specifying the address of the next router in the
path to a given destination network and the distance in hops.
The router uses the routing table to determine where and whether
to forward a packet. Each router periodically broadcasts its
routing table to other routers on each of its directly connected
networks, enabling them to compare and update their own tables
with the most recent record of connected networks and routes.
In this way, routing tables are kept current as changes are
made on the internet.
A hop is a unit count between networks on the internet. A hop
signifies “one router away.”
Device on the network.
File Transfer Protocol gives users the ability to transfer files
between IP hosts. It uses TCP to provide connection initiation
and reliable data transfer.
A computer with one or more uses that can act as an endpoint
of communication if it has TCP/IP.
Internet Control Message Protocol provides a means for intermediate
gateways and hosts to communicate. There are several types of
ICMP messages and they are used for several purposes including
IP flow control, routing table correction and host availability.
Internet Protocol which routes the data.
The basic unit of the information passed across and IP Internet.
It contains address information and data.
Packet InterNet Groper is a program which uses ICMP echo request
message to check if the specific IP address is accessible from
the current host.
A Destination point used by transport level protocols to distinguish
among multiple destinations within a given host computer.
An extension of the IP addressing scheme which enables an IP
site to use a single IP address for multiple physical networks.
Subnetting is applicable when a network grows beyond the number
of hosts allowed for the IP address class of the site.
Transmission Control Protocol ensures reliable, sequential,
delivery of data. TCP at each end of the connection ensures
that the data is delivered to the application accurately, sequential,
completely and free of duplicates. The application passes a
stream of bytes to TCP which breaks it into pieces, adds a header,
forming a segment, and then passes each segment to IP for transmission.
The TCP/IP standard protocol for remote terminal connection
service. A user can telnet from the local host to a host at
a remote site.
User Datagram Protocol provides simple, efficient protocol which
is connectionless and thus unreliable. The IP address contained
in the UDP header is used to direct the datagram to a specific
Any set of port numbers reserved for specific uses vy transport
level protocols (TCP & UDP). Well-known ports exist for
echo servers, time servers, telnet and FTP servers.
Synchronous Serial Interfaces
A serial interface between two devices which provides for bi-directional
data transfer as well as clocking. One device, the DCE, provides
the transmit and the receive timing to the second device, the
Communication Equipment (DCE)
This interfaces to the communication service’s transmission/reception
medium, and includes T1 Voice/Data Multiplexors, 64/56 Kilobit
DSU/ CSUs, and Fiber Optic Modems. The DCE provides the transmit
receive data pathways, along with their synchronous clocking
signals, that are used by the Engage Router’s DTE interface
for full duplex communication between the remotely interconnected
Terminal Equipment (DTE)
This equipment, such as an Engage Router, attaches to the terminal
side of Data Communication Equipment.
Carrier Detect (DCD)
A signal that indicates to the DTE that the DCE is receiving
a signal from a remote DCE.
Terminal Ready (DTR)
Prepares the DCE to be connected to the phone line, then the
connection can be established by dialing. Enables the DCE to
answer an incoming call on a switched line.