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3/08/2008

CCNA COURSE CISCO CH 10 ARABIC

عنونه IP

لقد تعلمت في الفصل "TCP/IP" عن بروتوكول التحكم بالإرسال/بروتوكول الانترنت (TCP/IP) وعمله لضمان الاتصال عبر أي مجموعة من الشبكات المترابطة ببعضها. ستتعلم في هذا الفصل تفاصيل عن فئات عناوين IP، وعناوين الشبكة والعُقد، وأقنعة الشبكات الفرعية. بالإضافة إلى ذلك، ستتعلم المفاهيم التي تحتاج إلى فهمها قبل ضبط تكوين عنوان IP.


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برعاية


CCNA COURSE CISCO CH 9 ARABIC

TCP\IP بروتوكول التحكم بالإرسال/بروتوكول الانترنت

الآن وقد تعلّمت عن عملية ضبط تكوين الموجّه، حان الوقت لتتعلم عن بروتوكول التحكم بالإرسال/بروتوكول الانترنت (TCP/IP). ستتعلم في هذا الفصل عن عمل TCP/IP لضمان اتصال عبر أي مجموعة من الشبكات المترابطة ببعضها. بالإضافة إلى ذلك، ستتعلم عن مكوّنات مكدس البروتوكول TCP/IP كالبروتوكولات لدعم إرسال الملفات، والبريد الإلكتروني، وتسجيل الدخول من بعيد، وأمور أخرى. بالإضافة إلى ذلك، ستتعلم عن البروتوكولات الموثوق وغير الموثوق بها لطبقة الإرسال وستتعلم عن تسليم وحدات البيانات الخالية من الاتصالات (الرزم) عند طبقة الشبكة. أخيراً، ستتعلم كيف يزوّد ICMP وظائف تحكم ورسائل عند طبقة الشبكة وكيف يعمل ARP وRARP.

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برعاية


CCNA COURSE CISCO CH 8 ARABIC

تكوين الموجّه الجزء الثانى

>إحدى الطرق لبدء فهم طريقة عمل الانترنت هي بضبط تكوين موجّه. إنه أيضاً أحد المواضيع الرئيسية في الامتحان CCNA، وأحد أهم المهارات التي يتطلبها أصحاب العمل. الموجّهات هي أجهزة معقّدة يمكن أن تكون لها مجموعة عريضة ومتنوعة من التكاوين الممكنة.
> في هذا الفصل، ستتمرن على ضبط تكوين موجّه. ستفعل ذلك عدة مرات. التمرن مع ظروف افتراضية وموجّهات فعلية هي الطريقة الوحيدة لتتعلم هذه المهارة المهمة جداً. رغم أن التكوين الفعلي سيكون بسيطاً نوعاً ما فإن هدف فعل ذلك عدة مرات هو لجعله "أمراً طبيعياً" بالنسبة لك.



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برعاية


CCNA COURSE CISCO CH 7 ARABIC

تكوين الموجّه

في الفصل "بدء تشغيل الموجّه وإعداده"، تعلمت كيفية تشغيل موجّه لأول مرة باستعمال الأوامر وتسلسل بدء التشغيل الصحيحة للقيام بتكوين أولي لموجّه. ستتعلم في هذا الفصل كيفية استعمال صيغ الموجّه وطرق التكوين لتحديث ملف تكوين موجّه بالإصدارات الحالية والسابقة للبرنامج سيسكو IOS




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برعاية


3/07/2008

CCNA COURSE CISCO CH 6 ARABIC

صور IOS

لقد تعلمت في الفصل "تكوين الموجّه" كيفية استعمال صيغ الموجّه وطرق التكوين لتحديث ملف تكوين الموجّه بالإصدارات الحالية والسابقة للبرنامج سيسكو IOS. ستتعلم في هذا الفصل كيفية استعمال مجموعة متنوعة من خيارات نظام سيسكو IOS المصدر، وتنفيذ أوامر لتحميل نظام سيسكو IOS إلى الموجّه، وصيانة الملفات الاحتياطية، وترقية نظام سيسكو IOS. بالإضافة إلى ذلك، ستتعلم عن وظائف مسجِّل التكوين وكيفية تحديد إصدار الملف الذي لديك. يشرح هذا الفصل أيضاً كيفية استعمال ملقم TFTP كمصدر للبرامج. عدة خيارات مصدر تزوّد مرونة وبدائل احتياطية. الموجّهات تستنهض نظام سيسكو IOS من:

§ الذاكرة الوامضة
§ الملقم TFTP
§ الذاكرة ROM (ليس نظام سيسكو IOS بأكمله)




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برعاية


3/03/2008

CCNA COURSE CISCO CH 5 ARABIC

بدأ تشغيل الموجه (الراوتر) واعداده للعمل

في الفصل "مكوّنات الموجّه"، تعلمت الإجراءات والأوامر الصحيحة
للوصول إلى موجّه، وفحص وصيانة مكوّناته، واختبار وصلته الشبكية.

في هذا الفصل، ستتعلم كيفية تشغيل موجّه لأول مرة باستعمال الأوامر
الصحيحة وتسلسل بدء التشغيل للقيام بتكوين أولي لموجّه.
بالإضافة إلى ذلك،
يشرح هذا الفصل تسلسل بدء التشغيل لموجّه
وحوار
الإعداد الذي يستعمله
الموجّه لإنشاء ملف تكوين أولي.

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برعاية

CCNA COURSE CISCO CH 4 ARABIC

مكونات الموجه (راوتر سيسكو)

الآن وقد أصبح لديك فهم عن واجهة سطر أوامر الموجّه، فقد حان الوقت
لفحص مكوّنات
الموجّه التي تضمن تسليماً فعّالاً للبيانات في الشبكة.
ستتعلم في هذا الفصل الإجراءات والأوامر الصحيحة للوصول إلى الموجّه
، وفحصه وصيانة
مكوّناته، واختبار وصلته الشبكية.

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برعاية

CCNA COURSE CISCO CH 3 ARABIC

واجهة استخدام سطر أوامر الموجه راوتر سيسكو

ستتعلم في هذا الفصل كيفية تشغيل موجّه لضمان تسليم بيانات على شبكة فيها موجّهات. ستصبح معتاداً على واجهة سطر الأوامر سيسكو.

ستتعلم كيفية:
• تسجيل الدخول بواسطة كلمة مرور المستخدم
• دخول الصيغة ذات الامتيازات بواسطة كلمة مرور التمكين
• التعطيل أو الإنهاء
بالإضافة إلى ذلك، ستتعلم كيفية استعمال ميزات المساعدة المتقدمة التالية:
• إكمال الأوامر وطلبات الإدخال
• فحص التركيب النحوي

أخيراً، ستتعلم كيفية استعمال ميزات التحرير المتقدمة التالية:
• التمرير التلقائي للسطر
• أدوات تحكم المؤشر
• دارئ المحفوظات مع استرداد الأوامر
ونسخ ولصق، المتوفرين في معظم الحاسبات

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برعاية

CCNA COURSE CISCO CH 2 ARABIC

الفصل الثانى

الآن وقد اكتسبت فهماً عن الطراز المرجعي وشبكات المناطق المحلية وعنونة ، أصبحت جاهزاً لتتعلم عن وتستعمل نظام سيسكو لكن قبل استعمالها، من المهم امتلاك فهم قوي عن شبكة المناطق الواسعة وأساسيات الموجّه. لذا، ستتعلم في هذا الفصل عن أجهزة شبكة المناطق الواسعة وتقنياتها ومواصفاتها القياسية. بالإضافة إلى ذلك، ستتعلم عن وظيفة الموجّه في شبكة المناطق الواسعة. أخيراً، ستنفّذ تمارين لها علاقة بإعداد الموجّه وضبط تكوينه.

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برعاية

CCNA COURSE CISCO CH 1 ARABIC

الفصل الأول

يعزّز فصل المراجعة هذا المفاهيم التي قد سبق أن تعلّمتها من قبل بخصوص الطراز المرجعي وشبكات المناطق المحلية وعنونة . إن فهم تلك المواضيع المتشعبة هي الخطوة الأولى نحو معرفة نظام سيسكو لتشغيل الشبكات البينية ، وهو الموضوع الرئيسي في منهج التعليم هذا، حيث يجب فهم مبادئ التشبيك البيني جيداً والمشروحة في هذا الفصل قبل محاولة فهم تشعبات نظام سيسكو


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برعاية

3/02/2008

CCNA COURSE CISCO INDEX TABLE ARABIC

جدول المحتويات / الفهرس الرئيسى

ويتضمن جدولا للمحتويات مبوبا حسب الفصول والأقسام وأرقام الصفحات
لكى يساعدك على الوصول الى الجزء الذى تريده بسهولة ويسر ولا تنسوا
مساندتنا بالضفط على اعلاـنــات جـوـجـل اعلى الصفحة وفى اليمين
ولكم جزيل الشكر

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برعاية

3/01/2008

CCNA COURSE CISCO CH 4 ENGLISH

Preparing Network Connections

he first three chapters of this book dealt with
an introduction to networking, networking
concepts, and IP addressing—basically theory
and concept information.
In this chapter, I’ll begin discussing the applied
side of networking. This chapter focuses on installing
your networking devices (switches and routers),
cabling up your LAN and WAN connections,
and establishing a console connection so that you
can put a configuration on these devices.
Once you have established a console connection
in this chapter, Chapter 5 will begin the basics of
using the router’s or switch’s command-line
interface (CLI) to put a basic configuration
on these devices.

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CCNA COURSE CISCO CH 3 ENGLISH

IP Addressing

The Transmission Control Protocol/Internet
Protocol (TCP/IP) is a standard that
includes many protocols. It defines
how machines on an internetwork can
communicate with each other.
It was initially funded by and developed
for DARPA (Defense Advanced Research
Protects Agency), which is a conglomeration
of U.S. military and government organizations.
Developed initially for the government, it was
later made available to the public, mainly seen
on Unix systems. First specified in RFC 791,
it has become the defacto standard for
networking protocols. The Internet uses
TCP/IP to carry data between networks,
and most corporations today use TCP/IP
for their networks. This chapter will
provide an overview of TCP/IP, including
some of its more important protocols,
as well as IP addressing.


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CCNA COURSE CISCO CH 2 ENGLISH

Networking Concepts

Before considering how to configure Cisco routers
and switches, you must be introduced to basic
networking concepts you’ll need to understand
in order to grasp the advanced concepts discussed
in later chapters. The OSI Reference Model is the
best place to start, since it will help you understand
how information is transferred between networking
devices. Of the seven layers in the OSI Reference
Model, be especially sure to understand how the
bottom three layers function, since most networking
devices function at these layers. This chapter discusses
information flow, as well as Cisco’s three-tiered
hierarchical model, which is used to design scalable,
flexible, and easy-to-troubleshoot-and-maintain
networks.


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2/29/2008

CCNA COURSE CISCO CH 1 ENGLISH

Networking Technologies

This chapter offers a brief introduction to networking
and some basic networking terms and concepts.
This material should be a review of many already
known concepts. You should be familiar with
the various networking topologies used in networks
, as well as different types of networks, such as
local area networks (LANs) and wide area networks
(WANs).

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LESSON 6 ARABIC

Lesson Title :

الدروس من السادس والثلاثون حتى الدرس الأخير

وبهذا نكون قد انتهينا بفضل الله من هذه السلسله

وفى المواضيع القادمة ان شاء الله سنقوم بعرض دورة السيسكو كامله

باللغتين العربيه والانجليزيه ومعها محاكيات سيسكو لأجهزة الراوتر

لزوم التدريبات

ولا تنسوا مسانده المدونة بالضغط على اعلانات جوجل التى بلأعلى

وعلى يمين الصفحة اذا وجدتم ما يناسبكم منها وهى تحتوى ايضا على مواقع هامة فى الشبكات

السلكيه واللاسلكية

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LESSON 5 ARABIC

Lesson Title :

الدروس من الحادى والثلاثين حتى الخامس والثلاثون

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LESSON 4 ARABIC

Lesson Title :

الدروس من الحادى والعشرون حتى الثلاثون

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2/25/2008

LESSON 3 ARABIC

Lesson Title :

الدروس من الحادى عشر الى العشرون

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LESSON 2 ARABIC

Lesson Title :

الدروس من الدرس الأول الى العاشر

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LESSON 1 ARABIC

Lesson Title :

مقدمه عن الشبكات

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2/20/2008

LESSON 4 ENGLISH

4.0 Networking protocols

4.1 TCP/IP Suite

TCP - Transmission Control Protocol, the most
common transport layer protocol used on
Ethernet
and the Internet. It was developed by DARPA.
TCP is built on top of the
Internet Protocol (IP)
and is nearly always seen in the combination
TCP/IP (TCP over IP).
It adds reliable
communication, flow-control, multiplexing
and connection-oriented
communication.
It provides full-duplex, process-to-process connections.


UDP
- User Datagram Protocol. Internet standard
network layer, transport layer and
session layer
protocols which provide simple but unreliable
datagram services. It adds a
checksum
and additional process-to-process addressing
information. UDP is a
connectionless protocol,
which, like TCP, is layered on top of IP. UDP neither
guarantees
delivery nor does it require a connection.
As a result it is lightweight and efficient, but all

error processing and retransmission must be taken
care of by the application program.


POP3
- Post Office Protocol version 3. POP3
allows a client computer to retrieve
electronic
mail from a POP3 server via a TCP/IP or other
connection. It does not provide
for sending mail,
which is assumed to be performed via SMTP
or some other method.
POP is useful for
computers without a permanent network
connection and which require
a "post office"
(the POP server) to hold their mail until they can
retrieve it.


SMTP
- Simple Mail Transfer Protocol, a protocol
used to transfer electronic mail
between computers,
usually over Ethernet. It is a server-to-server protocol,
so other
protocols are used to access the messages.
The SMTP dialog usually happens in the
background
under the control of the message transport system,
but it is possible to
interact with an SMTP server
using telnet to connect to the normal SMTP port, 25.


SNMP
- Simple Network Management Protocol,
the Internet standard protocol developed
to manage
nodes on an IP network. SNMP is not limited to TCP/IP
and can be used to
manage and monitor all sorts
of equipment including computers, routers, wiring hubs, etc.


FTP
- File Transfer Protocol, a client-server protocol
that allows a user on one computer
to transfer files
to and from another computer over a TCP/IP network.
Also the client
program the user executes to transfer files.

HTTP
- HyperText Transfer Protocol, the client-server
TCP/IP protocol used on the
World-Wide Web for
the exchange of HTML documents. It conventionally uses port 80.


IP
- Internet Protocol, the network layer for the TCP/IP
protocol suite widely used on
Ethernet networks.
IP is a connectionless, best-effort packet switching protocol. It

provides packet routing, fragmentation and re-assembly
through the data link layer.


PPP -
Point-to Point Protocol, the Internet standard
for transmitting network layer
datagrams
(e.g. IP packets)over serial point-to-point links.
PPP has a number of advantages over SLIP;
it is designed to operate both over
asynchronous
connections and bit-oriented synchronous
systems
and it can configure connections to a remote network

dynamically, and test that the link is usable. PPP can
be
configured to encapsulate different network layer
protocols
(such as IP, IPX, or AppleTalk) by using
the appropriate
Network Control Protocol (NCP).




2/18/2008

LESSON 3 ENGLISH

3.1 Networking Terms

Half-duplexing - A communication method,
which can carry
data in either direction but not
both directions at once.


Full-duplexing - A term used to describe
a communications
channel down which data
can travel in both directions at once.


LAN - Local Area Network. A data
communications network,
which is geographically,
limited (typically to a 1 mile radius)
allowing easy
interconnection of terminals, microprocessors

and computers within adjacent buildings.
Ethernet, Token-ring,
and FDDI are examples
of standard LANs.


WAN - Wide Area Network. Usually constructed
with serial
lines, extending over distances greater
than one mile.


Server - A computer, which provides some service
for other
computers, connected to it via a network.
The most common
example is a file server, which
has a local disk andservices requests
from remote
clients to read and write files on that disk.


Workstation - A general-purpose computer
designed to
be used by one person at a time
and which offers higher
performance than
normally found in a personal computer,
especially
with respect to graphics, processing power and the
ability
to carry out several tasks at the same time.
A device, which
accesses available resources from
servers typically found
in a distributed processing
environment .


Host - A computer connected to a network.
The term node includes
devices such as routers
and printers, which would not normally be

called "hosts".

Peer-to-Peer Network - A network that does
not rely on the
use of a central file server to share
files. Each workstation relies on
another workstation
to have it's resources made available. They are
very
difficult to maintain security, must be limited
number of peers to
keep administration costs low,
slow response time, but they are
inexpensive ,
no central point of failure and no special training required.


Server-based network - Requires a central file
server and a networking
operating system that can
handle the job. They require a separate machine

and therefore expensive hardware, expensive NOS,
and without the proper
training it is difficult to install
and maintain. On the other hand, data
transfer speeds
are greater, security is more robust, LAN expansion

is simpler, and there are management tools available.

Cable - provides the pathway for network
communications.
It's a component of a topology
determined by the NIC and standard
being used.
The most common types of LAN cabling are coaxial,

unshielded twisted pair, shielded twist pair, and fiber optic.

NIC - An adapter circuit board installed in
a computer to
provide a physical connection to a network.

Hub - A wiring concentrator for a LAN or WAN
that provides
a central attachment point for network
cabling. Coaxial cable
doesn't use hubs. There are
three types of hubs:

passive
(absorbs some signal; no electronics to
process data signal),

active (cleans signal; electronics to amplify signal),
and
intelligent (managed & switching hubs).
Switching hub - Intelligent hub, which contains
circuitry that very
quickly, routes signals between
ports on the hub. A communications
paradigm
in which a dedicated communication path is
established
between the sender and receiver
along which all packets travel.
The telephone
system is an example of a circuit switched network.

Also called connection-oriented.

MAU - Media Access Unit. In a Token Ring
network, a device to
attach multiplenetwork
stations in a star topology, internally wired

to connect the stations into a logical ring.
The MAU contains relays
to short out
non-operating workstations. Multiple MAUs
can be
connected into a larger ring through
their Ring In/Ring Out connectors.
Transceivers
( Transmitter-receiver) . The physical device, which

connects a host interface (e.g. an Ethernet controller)
to a local
area network. Ethernet transceivers contain
electronics that
apply signals to the cable and sense
other host's signals and collisions.


MAC address - Also known as the physical
addresses, operates on
the data link layer.
Each address is a unique 12-digit hexadecimal

ID number, which is hard coded to the network
adapter by the factory
, and is used by devices
to direct packets to other devices. Crossover cable

- A cable used to daisy-chain two network hubs
together. Can also be
used to connect two PCs
together and eliminate the need for a hub.


Default Gateway - The exit and entry point
of a subnet.
Subnetwork - A portion of a network,
which may be a physically
independent network
segment, which shares a network address

with other portions of the network and is
distinguished by a subnet
number.
A subnet is to a network what a network is
to an Internet.


Connectionless Protocol - The data
communication method
in which communication
occurs between hosts with no previous setup.

Packets sent between two hosts may take
different routes.
UDP is a connectionless
protocol. Also called packet switching. This is

on contrast to circuit switching, which is
connection-oriented.
Connection
-oriented Protocol - A type of transport layer
data
communication service that allows a host
to send data in a continuous
stream to another host.
The transport service will guarantee that all data

will be delivered to the other end in the same order
as sent and without
duplication. Communication
proceeds through three well-defined

phases: connection establishment, data transfer,
and connection
release. The most common
example is Transmission

Control Protocol (TCP).

Attenuation - The degrading of a signal as it
travels farther from
its origination. Crosstalk
- Signal overflow from one wire to another

adjacent wire. Jitter - Instability in a signal
wave; Caused by signal
interference or an
unbalanced FDDI Ring or Token Ring.


NOW WE HAVE FINISHED
THE THIRD LESSON ,
THE NEXT
LESSON I WILL EXPLAIN THE
PROTOCOLS
USED IN NETWORKING .




SEE YOU

2/15/2008

INTRODUCTION

WELCOME

Welcome to the NETWORKS blog .

Here you will find all you need to
start
a new way towards networks
configuration
and administration .

You will find a free lessons , free books
and all
what you need to be a successful
network administrator .


Thank you for joining me .

LESSON 1 ENGLISH

1.1 What is networking ?

Networking means connecting computers so that they can
share files, printers, applications, and other computer-
related resources. The advantages of networking
computers together are pretty obvious:

• Users can save their important files and documents
on a file server, which is more secure than storing
them on their workstations because a file server can
be backed up in a single operation.
• Users can share a network printer, which costs
much less than having a locally attached printer for
each user’s computer.
• Users can share groupware applications running on
application servers, which enables users to share
documents, send messages, and collaborate directly.
• The job of administering and securing a company’s
computer resources is simplified since they are
concentrated on a few centralized servers.
• This definition of networking focuses on the basic
goals of networking computers: increased
manageability, security, efficiency, and cost-
effectiveness over non-networked systems.

We could also focus on the different types of networks:

• Local area networks (LANs), which can range
from a few desktop workstations in a small
office/home office (SOHO) to several thousand
workstations and dozens of servers deployed
throughout dozens of buildings on a university
campus or in an industrial park
• Wide area networks (WANs), which might be a
company’s head office linked to a few branch
offices or an enterprise spanning several
continents with hundreds of offices and
subsidiaries
• The Internet, the world’s largest network and the
“network of networks”

We could also focus on the networking architectures
in which these types of networks can be implemented:

• Peer-to-peer networking, which might be
implemented in a workgroup consisting of
computers running Microsoft Windows 98 or
Windows 2000 Professional .
• Server-based networking, which might be based on
the domain model of Microsoft Windows NT, the
domain trees and forests of Active Directory in
Windows 2000, or another architecture such as
Novell Directory Services (NDS) for Novell
NetWare .
• Terminal-based networking, which might be the
traditional host-based mainframe environment;
the UNIX X Windows environment; the terminal
services of Windows NT 4, Server Enterprise
Edition; Windows 2000 Advanced Server .


1.2 Network Operating Systems

-Windows NT
A networking operating system designed using a Directory
to manage certain resources.
NT's primary file system is NTFS. Provides an inherently
GUI console at the server.
Clients - Windows NT Workstation best serves Windows NT
Server because of the common NTFS file system and they
are optimized to work best with each other.
However, Windows95/98, Windows for Workgroups, DOS, UNIX,
Macintosh, and even NetWare clients can be connected to
a Windows NT environment.

-UNIX
UNIX is a command line operating system written in
the C programming language. GUI interface can be
achieved by installing special software such as X-Windows. Used
mainly in a multi-user environment on minicomputers.
Several different version available and allows a great deal
of flexibility when performing network operations.
Many UNIX protocols are the standard for today’s Internet.
Clients - Unix specific clients such as Sun Sparc stations work
best with their manufacturer's Network Operating System (NOS).

-Novell NetWare
A networking operating system designed using a bindery
or Directory Service to manage most resources.
NetWare’s primary file system is a combination of FAT (File Allocation
Table) and DET (Directory Entry Table). Provides an inherently text
based and command prompt console at the server.
Clients - Novell NetWare works well with most popular clients
such as DOS, Windows 3.11, Windows 9x, Windows NT Workstation.

THUS WE HAVE FINISHED THIS LESSON , I AM WAITNG YOUR
QUESTIONS AND SUGGESTIONS , SEE YOU

LESSON 2 ENGLISH

2.1 The OSI Model

The Open System Interconnection (OSI) Model is a seven
layer model that helps designers of network operating
systems and software to create relatively standardized software.
This is useful when trying to get different operating systems to talk
to each other. Although the model is only a blueprint, it is
almost universally followed.

*NOTE*
The OSI model graphical explanation is available at this link

http://www.4shared.com/file/37894066/
cbcacee0/The_OSI_Model__1_.html


2.2 Networking Devices

Internetworking devices offer communication between
local area network (LAN) segments. There are five
primary types of internetworking devices:

repeaters, bridges, routers, brouters, and gateways.
The OSI layer at which they establish the LAN-to-LAN
connection can differentiate these devices very generally.
Each device offers the functionality found at its layer(s)
of connection and uses the functionality of all lower layers.

-Repeater (Physical) A network device used to regenerate or
replicate a signal. Repeaters are used in transmission systems
to regenerate analog or digital signals distorted by
transmission loss. Analog repeaters frequently can
only amplify the signal while digital repeaters can
reconstruct a signal to near its original quality.
In a data network, a repeater can relay messages
between subnetworks that use different protocols or
cable types. Hubs can operate as repeaters by
relaying messages to all connected computers. A
repeater cannot do the intelligent routing performed
by bridges and routers.

-Bridge (Data Link) A device that connects two
local-area networks (LANs), or two segments of
the same LAN .
The two LANs being connected can be alike or
dissimilar. For example, a bridge can connect an
Ethernet with a Token-Ring network.
Unlike routers, bridges are protocol independent.
They simply forward packets without analyzing and
re-routing messages. Consequently, they're faster
than routers, but also less versatile.

-Router (Network) A device that connects two LANs.
Routers are similar to bridges, but provide additional
functionality, such as the ability to filter messages
and forward them to different places based on
various criteria.
The Internet uses routers extensively to forward
packets from one host to another.
Brouter Data Link/Network Short for bridge router,
a device that functions as both a router and a bridge.
A brouter understands how to route specific types of packets,
such as TCP/IP packets. Any other packets it receives are
simply forwarded to other network(s) connected to
the device (this is the bridge function).

-Gateway (Top 4 layers) In networking, a combination of
hardware and software that links two different types of networks.
Gateways between e-mail systems, for example,
allow users on different e-mail systems to exchange
messages.