Download server-based network

An Introduction
to Networking
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Networks and Standalone
Computers
 Network
– Group of computers and other devices
connected by some type of transmission media
– Networks enable users to share devices and
data, collectively called a network’s
resources
 Standalone computer
– Uses programs and data only from its local
disks and is not connected to a network
Sneakernet
 Method of sharing data by copying it to a disk
and carrying the disk from computer to computer
Local and Remote Computers
 Local computer
– Computer on which user is working
 Remote computer
– Computer that user controls or works on via
network connection
Peer-to-Peer Network
 Computers communicate on single segment of cable and
share each other’s data and devices
 Simple example of a local area network (LAN)
Local Area Network (LAN)
 Network of computers and other devices
confined to relatively small space
 LANs involving many computers are
usually server-based
– On a server-based network, special
computers (known as servers) process data
for and facilitate communication between
other computers on the network (known as
clients)
Networking Basics
 Workstation
– Computer that typically runs a desktop
operating system and connects to a network
 Client/server architecture
– Networking model in which clients use central
server to share applications, devices, and data
Networking Basics
 Client/server network
– Network based on client/server architecture
 Network operating system
– Special software designed to manage data and
other resources on a server for a number of
clients
Networking Basics
Advantages of Server-Based
over Peer-to-Peer Networks
 User login accounts and passwords can be
assigned in one place
 Access to multiple shared resources can be
centrally granted
 Servers are optimized to handle heavy
processing loads and dedicated to handling
requests from clients
 Servers can connect more than a handful of
computers
MANs and WANs
 Metropolitan area network (MAN)
– Network connecting clients and servers in
multiple buildings within limited geographic
area
 Wide area network (WAN)
– Network that spans large distance and connects
two or more LANs
– The Internet is an example of a very intricate
and extensive WAN that spans the globe
WAN
Elements Common to All
Server-Based Networks
 Client
– In addition to referring to a computer on the
network, may also refers to human user of
client workstation
 Server
 Workstation
 Network interface card (NIC)
– Enables workstation to connect to the network
and communicate with other computers
Elements Common to All
Server-Based Networks
Elements Common to All
Server-Based Networks
 Network operating system (NOS)
 Host
– Server that manages shared resources
 Node
– Client, server, or other device that can
communicate over a network and that is
identified by a unique identifying number,
known as its network address
Elements Common to All
Server-Based Networks
 Protocol
– Rules network uses to transfer data
 Data Packets
– The distinct units of data transmitted from one
computer to another on a network
Elements Common to All
Server-Based Networks
 Addressing
– Scheme for assigning unique identifying
number to every workstation on network
– The number that uniquely identifies each
workstation and device on a network is its
address
Elements Common to All
Server-Based Networks
 Transmission
media
– Means
through
which data
are
transmitted
and received
How Networks Are Used
 Services
– Features provided by a network
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File and print services
Communications services
Mail services
Internet services
Management services
MDF in a Multi-Story Building
MDF in a Multi-Building
Campus
Horizontal and Backbone
Cabling (Type A)
MDF
IDF
3000m
The Seven Layers of the OSI
Model
International
Organization of
Standardization
ISO
Layer7
 The application layer is the
OSI layer that is closest to
the user; it provides
network services to the
user’s applications. It
differs from the other
layers in that it does not
provide services to any
other OSI layer, but rather,
only to applications outside
the OSI model. Examples
of such applications are
spreadsheet programs,
word processing
programs, and bank
terminal programs. If you
want to remember Layer 7
in as few words as
possible, think of
browsers.
Layer 6
 The presentation layer
ensures that the
information that the
application layer of one
system sends out is
readable by the
application layer of
another system. If
necessary, the
presentation layer
translates between
multiple data formats by
using a common format.
If you want to think of
Layer 6 in as few words
as possible, think of a
common data format
Layer 5
 As its name implies, the
session layer establishes,
manages, and terminates
sessions between two
communicating hosts.
The session layer
provides its services to
the presentation layer. It
also synchronizes
dialogue between the two
hosts' presentation layers
and manages their data
exchange. If you want to
remember Layer 5 in as
few words as possible,
think of dialogues and
conversations.
Layer 4
 The transport layer segments
data from the sending host's
system and reassembles the
data into a data stream on the
receiving host's system.
Layer 4 is the boundary
between media-layer
protocols and host-layer
protocols. Layer 4 also deals
with Flow Control
(Windowing), and Reliability
of Communication
(Acknowledgement).
Layer 3
 The network layer is a
complex layer that
provides connectivity
and path selection
between two host
systems that may be
located on
geographically
separated networks. If
you want to remember
Layer 3 in as few words
as possible, think of
path selection, routing,
and addressing.
Layer 2
 The data link layer
provides reliable transit of
data across a physical
link. In so doing, the data
link layer is concerned
with physical (as opposed
to logical) addressing,
network topology,
network access, error
notification, ordered
delivery of frames. If you
want to remember Layer
2 in as few words as
possible, think of frames
and media access
control.
Layer 1
 The physical layer defines
the electrical, mechanical,
procedural, and functional
specifications for activating,
maintaining, and
deactivating the physical link
between end systems. Such
characteristics as voltage
levels, timing of voltage
changes, physical data
rates, maximum
transmission distances,
physical connectors, and
other, similar, attributes are
defined by physical layer
specifications. If you want to
remember Layer 1 in as few
words as possible, think of
signals and media.
Encapsulation
Summary of the OSI Model
Layer
Description
5 Conversion Steps to
Encapsulate Data