Title: CCNA SEMESTER 1 V 3.0
1CCNA SEMESTER 1 V 3.0
2Students completing this chapter should be able
to
- Explain the importance of bandwidth in
networking. - Use an analogy from their experience to explain
bandwidth. - Explain the difference between bandwidth and
throughput. - Calculate data transfer rates.
- Explain why layered models are used to describe
data communication. - Explain the development of the Open System
Interconnection model (OSI). - List the advantages of a layered approach.
- Identify each of the seven layers of the OSI
model. - Identify the four layers of the TCP/IP model.
- Describe the similarities and differences between
the two models. - Briefly outline the history of networking.
- Identify devices used in networking.
- Understand the role of protocols in networking.
- Define LAN, WAN, MAN, and SAN.
- Explain VPNs and their advantages.
- Describe the differences between intranets and
extranets. -
3Networking Fundamentals
4Evolution of Networking
5Local Area Networks (LAN)
- Businesses needed a
- solution that would
- successfully address the
- following three problems
- How to avoid duplication of equipment and
resources - How to communicate efficiently
- How to set up and manage a network
6Wide-area networks (WANs)
- A way for information to move efficiently and
quickly - WANs could connect user networks over large
geographic areas
7Examples of data Networks
8Networking Devices
- Equipment that connects directly to a network
segment is referred to as a device. These devices
are broken up into two classifications. - Network Devices
- end-user devices
9End user devices
- End-user devices that provide users with a
connection to the network are also referred to as
hosts - These devices allow users to share, create, and
obtain information. - Host devices are physically connected to the
network media using a network interface card
(NIC)
10Network interface card(NIC)
- A NIC is a printed circuit board that fits into
the expansion slot of a bus on a computer
motherboard, or it can be a peripheral device.
11Network interface card(NIC)
- Laptop or notebook computer NICs are usually the
size of a PCMCIA card. - Each individual NIC carries a unique code, called
a Media Access Control (MAC) address
12End User Devices
13Network devices
- Network devices provide transport for the data
that needs to be transferred between end-user
devices. Network devices provide extension of
cable connections, concentration of connections,
conversion of data formats, and management of
data transfers.
14Network Devices
15Repeater
- A repeater is a network device used to regenerate
a signal. Repeaters regenerate analog or digital
signals distorted by transmission loss due to
attenuation.
16Bridges
- convert network transmission data formats as well
as perform basic data transmission management. - provide connections between LANs.
- perform a check on the data to determine whether
it should cross the bridge or not. This makes
each part of the network more efficient
17Bridges
18Switches
- Workgroup switches add more intelligence to data
transfer management. - They can determine whether data should remain on
a LAN or not - They can transfer the data only to the connection
that needs that data.
19Switches
20Routers
- Routers have all the capabilities listed above.
- regenerate signals
- concentrate multiple connections
- convert data transmission formats, and manage
data transfers - They can also connect to a WAN, which allows them
to connect LANs that are separated by great
distances
21Network topology
- Network topology defines the structure of the
network. One part of the topology definition is
the physical topology, which is the actual layout
of the wire or media. The other part is the
logical topology, which defines how the media is
accessed by the hosts for sending data
22Logical topology
- The logical topology of a network is how the
hosts communicate across the medium - - broadcast
- Ethernet
- - token passing
- Token Ring
- Fiber Distributed Data
Interface (FDDI) -
23Different topologies
24A protocol
- A protocol is a formal description of a set of
rules and conventions that govern a particular
aspect of how devices on a network communicate. - Protocols determine the format, timing,
sequencing, and error control in data
communication
25Protocols
- Protocols control all aspects of data
- communication, which include the following
- (IEEE, ANSI , TIA , EIA , ITU )
- How the physical network is built
- How computers connect to the network
- How the data is formatted for transmission
- How that data is sent
- How to deal with errors
26Local-area networks (LANs)
- LANs consist of the
- following components
- Computers
- Network interface cards
- Peripheral devices
- Networking media
- Network devices
- Some common LAN
- technologies are
- Ethernet
- Token Ring
- FDDI
27LANs technologies
28Wide-area networks (WANs)
- WANs interconnect LANs, which then provide access
to computers or file servers in other locations.
- Some common WAN
- technologies are
- Modems
- Integrated Services Digital Network (ISDN)
- Digital Subscriber Line (DSL)
- Frame Relay
- US (T) and Europe (E) Carrier Series T1, E1,
T3, E3 - Synchronous Optical Network (SONET)
29WANs and WAN Devices
30Metropolitan-area networks (MANs)
- A MAN is a network that spans a metropolitan area
such as a city or suburban area. A MAN usually
consists of two or more LANs in a common
geographic area .
31Storage-area networks (SANs)
- A SAN is a dedicated, high-performance network
used to - move data between servers and storage resources
- SANs offer the following features
- Performance SANs enable concurrent access of
disk or tape arrays by two or more servers at
high speeds. - Availability SANs have disaster tolerance built
in, because data can be mirrored using a SAN up
to 10 kilometers (km) or 6.2 miles away. - Scalability Like a LAN/WAN, it can use a
variety of technologies. This allows easy
relocation of backup data, operations, file
migration, and data replication between systems.
32Storage-area networks (SANs)
33Virtual private network (VPN)
- A VPN is a private network that is constructed
within a public network infrastructure such as
the global Internet. Using VPN, a telecommuter
can access the network of the company
headquarters through the Internet by building a
secure tunnel between the telecommuters PC and a
VPN router in the headquarters
34Types of VPNs
- Access VPNs Access VPNs provide remote access
to a mobile worker and small office/home office
(SOHO) to the headquarters of the Intranet or
Extranet over a shared infrastructure. - Intranet VPNs Intranet VPNs link regional and
remote offices to the headquarters of the
internal network over a shared infrastructure
using dedicated connections - Extranet VPNs Extranet VPNs link business
partners to the headquarters of the network over
a shared infrastructure using dedicated
connections
35Benefits of VPNs
- A VPN is a service that offers secure, reliable
connectivity over a shared public network
infrastructure such as the Internet. - They are the most cost-effective method of
establishing a point-to-point connection between
remote users and an enterprise customer's network
36Intranets and extranets
- Intranets are designed to permit access by users
who have access privileges to the internal LAN of
the organization. - Extranets refer to applications and services that
are Intranet based, and use extended, secure
access to external users or enterprises.
37Importance of bandwidth
- Bandwidth is defined as the amount of information
that can flow through a network connection in a
given period of time.
38Pipe Analogy for Bandwidth
39Highway Analogy for Bandwidth
40Measurement
- In digital systems, the basic unit of bandwidth
is bits per second (bps). Bandwidth is the
measure of how much information, or bits, can
flow from one place to another in a given amount
of time, or seconds.
41Limitations
- Bandwidth varies depending upon the type of media
as well as the LAN and WAN technologies used. The
physics of the media account for some of the
difference. - The actual bandwidth of a network is determined
by a combination of the physical media and the
technologies chosen for signaling and detecting
network signals.
42Distance and bandwidth
43File Transfer Time Calculations
44Throughput
- Throughput refers to actual measured bandwidth,
at a specific time of day, using specific
Internet routes, and while a specific set of data
is transmitted on the network
45Digital versus analog
- Electromagnetic waves are called analog because
they have the same shapes as the light and sound
waves produced by the transmitters - Analog bandwidth is measured by how much of the
electromagnetic spectrum is occupied by each
signal. The basic unit of analog bandwidth is
hertz (Hz), or cycles per second. - In digital signaling all information is sent as
bits, regardless of the kind of information it
is. Voice, video, and data all become streams of
bits when they are prepared for transmission over
digital media. - Unlimited amounts of information can be sent over
the smallest or lowest bandwidth digital channel.
46Networking Models
- The concept of layers is used to describe
communication from one computer to another - As the data passes between layers, each layer
adds additional information that enables
effective communication with the corresponding
layer on the other computer - The OSI and TCP/IP models have layers that
explain how data is communicated from one
computer to another.
47Network Comparisons
48Layer Communication
- Layer 4 on the source computer communicates with
Layer 4 on the destination computer. The rules
and conventions used for this layer are known as
Layer 4 protocols.
49OSI model
50OSI layers
- The OSI reference model explains how packets
travel through the - various layers to another device on a network
- Dividing the network into seven layers provides
the following - advantages
- It breaks network communication into smaller,
more manageable parts. - It standardizes network components to allow
multiple vendor development and support. - It allows different types of network hardware and
software to communicate with each other. - It prevents changes in one layer from affecting
other layers. - It divides network communication into smaller
parts to make learning it easier to understand.
51The OSI Model - Layer 1
52The OSI Model - Layer 2
53The OSI Model - Layer 3
54The OSI Model - Layer 4
55The OSI Model - Layer 5
56The OSI Model - Layer 6
57The OSI Model - Layer 7
58Peer-to-peer communications
- Each layer of the OSI model at the source
communicate with its peer layer at the
destination - The protocols of each layer exchange information,
called protocol data units (PDUs). - Each layer depends on the service function of the
OSI layer below it. - The lower layer uses encapsulation to put the PDU
from the upper layer into its data field then it
adds whatever headers and trailers the layer
needs to perform its function.
59Peer-to-peer communications
60TCP/IP model
- Application layer handles issues of
representation, encoding, and dialog control. - The transport layer deals with the quality of
service issues of reliability, flow control, and
error correction - Internet layer divides TCP segments into packets
and send them from any network - Network layer is concerned with all of the
components, both physical and logical, that are
required to make a physical link
61Common TCP/IP Protocols
The relationship between IP and TCP is an
important one. IP can be thought to point the way
for the packets, while TCP provides a reliable
transport
62Comparing TCP/IP with OSI
TCP
IP
Ethernet
63Detailed encapsulation process
- If one computer (host A) wants to send data to
another computer (host B), the data must first be
packaged through a process called encapsulation. - Encapsulation wraps data with the necessary
protocol information before network transit.
64Data Encapsulation
65Data Encapsulation example
66An understanding of the following key points
should have been achieved
- Understanding bandwidth is essential when
studying networking - Bandwidth is finite, costs money, and the demand
for it increases daily - Bandwidth is measured in bits per second, bps,
kpbs, Mbps, or Gbps - Limitations on bandwidth include type of media
used, LAN and WAN technologies, and network
equipment - Throughput refers to actual measured bandwidth,
which is affected by factors that include number
of users on network, networking devices, type of
data, users computer and the server - The formula TS/BW (transfer time size of file
/ bandwidth) can be used to calculate data
transfer time - Comparison of analog and digital bandwidth
67An understanding of the following key points
should have been achieved
- Network communication is described by layered
models - The OSI and TCP/IP are the two most important
models of network communication - The International Organization for
Standardization developed the OSI model to
address the problems of network incompatibility - The seven layers of the OSI are application,
presentation, session, transport, network, data
link, and physical - The four layers of the TCP/IP are application,
transport, internet, and network access - The TCP/IP application layer is equivalent to the
OSI application, presentation, and session layers
- Fundamental networking devices are hubs, bridges,
switches, and routers - The physical topology layouts include the bus,
ring, star, extended star, hierarchical, and mesh
- A WAN consists of two or more LANs spanning a
common geographic area
68An understanding of the following key points
should have been achieved
- A SAN provides enhanced system performance, is
scalable, and has disaster tolerance built in - A VPN is a private network that is constructed
within a public network infrastructure - Three main types of VPNs are access, Intranet,
and Extranet VPNs - Intranets are designed to be available to users
who have access privileges to the internal
network of an organization - Extranets are designed to deliver applications
and services that are Intranet based, using
extended, secured access to external users or
enterprises
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