Transcript peripherals

Week one - networks and
Layered Communication
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Introduction to Networks
Layered Communication
OSI Model
The Physical Layer
The Data Link Layer
Introduction to Networking (1)
• Understand the concept of Networking
– Definition
– What can be Networked
– Reasons for Networking
• Understand the concept of an individual PC
• Understand wide variety of computer types
– PC
– MACINTOSH
– Mainframe
Introduction to Networking (2)
• Understand that what is important in
Networking is the Protocol used
• Terminology used to describe Networks
– LANs
– WANs
– MANs
• Understand the difficulty of Networking a
wide
– variety of Networks
– Hardware
– Software
Networking
• Connecting of any collection of computers,
printers, routers, switches, and other
devices for the purpose of communication
over some transmission medium.
Protocol
• Formal description of a set of rules and
conventions that govern how devices on a
network exchange information.
LAN, WAN and MAN (1)
• Local-area network [LAN]
– High-speed, low-error data network covering a
relatively small geographic area. LANs connect
workstations, peripherals, terminals, and other
devices in a single building or other
geographically limited area. LAN standards
specify cabling and signaling at the physical
and data link layers of the OSI model. Ethernet,
FDDI, and Token Ring are widely used LAN
technologies.
LAN, WAN and MAN (2)
• Wide Area Network [WAN]
– Data communications network that serves
users across a broad geographic area and
often uses transmission devices provided by
common carriers. Frame Relay, SMDS, and X.25
are examples of WANs.
LAN, WAN and MAN (3)
• Metropolitan-area network (MAN)
– Network that spans a
metropolitan area. Generally, a MAN spans a
larger geographic area than a
LAN, but a smaller geographic area than a WAN.
Compare with LAN and
WAN.
Hardware and Software
• hardware - A term used in computing to
refer to physical parts or equipment.
• Software - A term used in computing to
refer to programs or applications.
What is Networking?
• Networking is the interconnection of
workstations, peripherals terminals and
other devices. One of the most common
types of networks is the Local Area Network
or LAN.
• Peripherals
– Device connected to a computer to provide
auxiliary functions such as printing, added
disk space, scanning or CD-Rom
Why and how did networking
start?
• Applications written for business helped create
the PC industry. [Why]
• Early computers were standalone devices. [Why]
• One early solution to these problems was the
creation of local area networks, or LANs. [When]
– What was needed was a way to move
information efficiently and quickly from one
business to another. The solutionwas the
creation of metropolitan area networks, or
MANs, and wide area networks, or WANs.
Why were networking standards
needed?
• Because many of the emerging network
technologies were built using different
hardware and software implementations,
one problem that soon surfaced was that
many of the new network technologies
were incompatible. Increasingly, it became
difficult for networks using different
specifications to communicate with each
other.
OSI Model
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Understand concept of standards
Understand that OSI Model is model for
Know names of 7 layers of the OSI model
Understand what encapsulation is
Understand why it is desirable to network
Understand what data is data packet
Understand what a source is
• Understand what a destination is
What model was developed to
describe networking?
• To address the problem, the International
Organization for Standardization (ISO) researched
networks schemes like DECNET, SNA, and TCP/IP.
As a result of this research, the ISO recognized
there was a need to create a network model that
would help vendors create networks that would
work compatibly and interoperably with other
networks. The OSI Reference Model, released in
1984, was the descriptive scheme they created.
By creating the OSI model, the ISO was providing
vendors with a set of standards .
What is the OSI Reference
Model?
• The OSI (Open System Interconnection]
reference model is not something tangible.
Rather it is a conceptual framework
specifying the network functions that
occur at each layer. In simpler terms, a
model is a way of picturing how information
travels through networks.
What process does the OSI
Reference Model describe?
• Each of the seven problem areas is solved
by a layer of the model. The seven layers of
the OSI reference model are: the physical
layer, the data link layer, the network layer,
the transport layer, the session layer, the
presentation layer, and the application
layer.
Why is Networking desirable?
• By networking or connecting computers,
printers, routers, switches, and other
devices so that they can communicate with
each other, it is possible to share
information, resources, or get to the
Internet.
How does encapsulation allow
computers to communicate data?
• The information that is sent on a network is
referred to as data or data packets.
How does encapsulation allow
computers to communicate data?
• If one computer (host A) wants to send data to another
computer (host B), the data must first be packaged in a
process called encapsulation.
What is the first building block of the
OSIReference Model?
• In the OSI model, this foundation is called
the Physical layer.
The function of the physical layer
• It is the transmission of data. Typically
such transmission is accomplished
through the use of such things as wires,
connectors, and voltages.
How is information stored in
computers?
• Information in computers is stored using the binary
number system, in which the only possible symbols, or
binary digits, 0 or 1.
What types of materials might
one see in the Physical layer of
the OSI model?
• The materials used to connect computers
vary. They include twisted pair, coaxial, and
fiber-optic cable.
What are some criteria for
determining what type of media
will be used?
• The type of connecting material used by a
network will determine things such as how
much data and how fast the data can travel
across the network.
How do computers identify
themselves? [Data link Layer]
• Every computer has a unique way of
identifying itself. Every computer whether
it is attached to a network or not has a
physical address. No two physical
addresses are ever alike. Referred to as the
Media Access Control Address or MAC
Address, the physical address is located on
the Network Interface Card or NIC Card.
The Network card
Where is the NIC card on the OSI
model?
• It is located in that the data link layer, layer
2, where the MAC address is located,