SEMESTER 1 CHAPTER 2
Communicating over the Network
V 4.0
2.0.1
What are the five aspects of
the information network we
will focus on in this course?
2.1.1
What are the three
elements of
communication?
What is the definition of the
term network for this
course?
2.1.2
What would happen to the
network if a message was
sent as one massive
continuous stream of bits?
Define segmentation of
messages
What are the 2 advantages
of segmentation?
What is multiplexing?
2.1.3
2.1.4
What is hardware on a
network?
What are end devices on a
network?
What is the definition of a
host?
What is the definition of a
server?
What is the definition of a
client?
2.1.5
List examples of
Devices that make up the network
Media that connect the devices
Messages that are carried across the network
Rules and processes that govern network
communications
Tools and commands for constructing and
maintaining networks
Sender, Receiver, Chanell
data or information networks capable of
carrying many different types of
communications, including traditional computer
data, interactive voice, video, and
entertainment products.
no other device would be able to send or
receive messages on the same network while
this data transfer was in progress
division of the data stream into smaller pieces
many different conversations can be
interleaved on the network
segmentation can increase the reliability of
network communications
process used to interleave the pieces of
separate conversations together on the
network
the visible components of the network platform
Computers (work stations, laptops, file servers,
web servers)
Network printers
VoIP phones
Security cameras
Mobile handheld devices (such as wireless
barcode scanners, PDAs)
either the source or destination of a message
transmitted over the network
hosts that have software installed that enables
them to provide information and services
hosts that have software installed that enables
them to request and display the information
obtained from the server
Network Access Devices (Hubs, switches, and
intermediary devices.
List examples of process
that intermediary devices
perform.
2.1.6
What are the 3 primary
types of media used in
modern networks?
What criteria should be
used to select network
media?
2.2.1
What are the ways in which
network infrastructure can
vary?
What is the definition of a
LAN?
2.2.2
What is the definition of a
WAN?
What is an internetwork?
2.2.3
What is an intranetwork?
2.2.4.1 Define a NIC
Define a physical port
Define an interface
2.2.4.2 Complete the Packet Tracer
wireless access points)
Internetworking Devices (routers)
Communication Servers and Modems
Security Devices (firewalls)
Regenerate and retransmit data signals
Maintain information about what pathways
exist through the network and internetwork
Notify other devices of errors and
communication failures
Direct data along alternate pathways when
there is a link failure
Classify and direct messages according to
QoS priorities
Permit or deny the flow of data, based on
security settings
Metallic wires within cables
Glass or plastic fibers (fiber optic cable)
Wireless transmission
The distance the media can successfully carry
a signal.
The environment in which the media is to be
installed.
The amount of data and the speed at which it
must be transmitted.
The cost of the media and installation
The size of the area covered
The number of users connected
The number and types of services available
individual network usually spans a single
geographical area, providing services and
applications to people within a common
organizational structure
networks that connect LANs in geographically
separated locations
A global mesh of interconnected networks
(internetworks) meets these human
communication needs.
a private connection of LANs and WANs that
belongs to an organization, and is designed to
be accessible only by the organization's
members, employees, or others with
authorization
provides the physical connection to the
network at the PC or other host device.
A connector or outlet on a networking device
where the media is connected to a host or
other networking device.
Specialized ports on an internetworking device
that connect to individual networks.
2.2.5
2.3.1
2.3.2
Lab and save your results
You can skip this lab
What are the 3 layers of
protocols described?
What process do
networking layer protocol
suites describe?
What is proprietary?
2.3.3
2.3.4
What does the use of
standards and protocols
provide?
What is an application
protocol?
What is a Transport
Protocol?
What is the Internetwork
Protocol
What is the Network Access
Protocol?
2.3.5
2.4.1
2.4.2
2.4.3
What do networking
protocols describe?
What are the benefits of
using a layered model to
describe networking?
What are the two basic
types of networking
models?
What are the two primary
models used when
describing networking?
What is done at the
Application Layer?
Content Layer, Rules Layer, Physical Layer
The format or structure of the message
The process by which networking devices
share information about pathways with other
networks
How and when error and system messages
are passed between devices
The setup and termination of data transfer
sessions
one company or vendor controls the definition
of the protocol and how it functions
products from different manufacturers can
work together for efficient communications
defines the content and formatting of the
requests and responses exchanged between
the client and server
manages the individual conversations between
web servers and web clients
responsible for taking the formatted segments
from TCP, encapsulating them into packets,
assigning the appropriate addresses, and
selecting the best path to the destination host.
Network access protocols describe two
primary functions, data link management and
the physical transmission of data on the media.
the functions that occur during network
communications
Assists in protocol design, because protocols
that operate at a specific layer have defined
information that they act upon and a defined
interface to the layers above and below.
Fosters competition because products from
different vendors can work together.
Prevents technology or capability changes in
one layer from affecting other layers above
and below.
Provides a common language to describe
networking functions and capabilities.
protocol models and reference models
TCP/IP and OSI
Represents the data to the user plus encoding
and dialog control
2.4.4
What is done at the
Transport Layer?
What is done at the Internet
Layer?
What is done at the Network
Access Layer?
What are the seven steps in
a complete communication
process?
Supports communication between diverse
devices across diverse neworks
Determines the best path through the network
Controls the hardware devices and media that
make up the network
1. Creation of data at the application layer of
the originating source end device
2. Segmentation and encapsulation of data as
it passes down the protocol stack in the source
end device
3. Generation of the data onto the media at the
network access layer of the stack
4. Transportation of the data through the
internetwork, which consists of media and any
intermediary devices
5. Reception of the data at the network access
layer of the destination end device
6. Decapsulation and reassembly of the data
as it passes up the stack in the destination
device
2.4.5
What is the PDU for the
application layer?
What is the Transport Layer
PDU?
What is the PDU for the
Internet Layer?
What is the PDU for the
Network Access Layer?
What PDU is used when
physically transporting the
information over the
medium?
2.4.6.1 How is the protocol stack
processed when sending
information?
2.4.6.2 What is the process use at
the receiving end called?
2.4.7
What are the seven layers
of the OSI Model?
2.4.8
Which Layers of the OSI
7. Passing this data to the destination
application at the Application layer of the
destination end device
Data
Segment
Packet
Frame
Bits
Top to bottom
Decapsulation
Application, Presentation, Session, Transport,
Network, Data Link, Physical
Application, Presentation, Session-Application
Model parallel with the
TCP/IP Model?
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.6.1
2.6.2
What does the physical
layer do?
What addresses does the
data link layer use?
What address does the
network layer use?
What does the transport
layer use?
What do the upper layers
use?
What is the PDU for Layer 2
called
What is the layer 2 address
called?
What happens after the
frame has reached its’
destination?
What are layer 3 devices
primarily designed for?
What address is used at
Layer 3?
What is the PDU of the
Layer 3 information?
Which device decapsulates
the frame at the edge of a
network?
What does a router do?
What happens when the
frame reaches the end
device?
What does the information
in the frame provide at
Layer 4?
How is each application or
service represented at
Layer 4?
The movie is pretty good if
you can download it.
Complete the Packet Tracer
Lab and save your network
when completed. E-mail the
file
Complete the Packet Tracer
Lab and save your network
Transport-Transport
Internet-Network
Data Link, Physical-Network Access
Timing and synchronization of bits
Destination and source physical address
Destination and source logical address
Destination and source process number (ports)
Encoded application data
Frame
MAC address
the Layer 2 address information is removed as
the data is decapsulated and moved up the
protocol stack to Layer 3
to move data from one local network to
another local network within an internetwork
IP address
Packet
Router
use the network identifier portion of this
address to determine which path to use to
reach the destination host
the frame and packet headers are removed
and the data moved up to Layer 4
identifies the specific process or service
running on the destination host device that will
act on the data being delivered
Port number
when completed. E-mail the
file
2.7.1.3 **Extra Credit***
Complete this Packet
Tracer Lab, save the file,
and email it to me.
* What are the intermediary devices? What are their functions?
 Processes running on the intermediary network devices perform these functions:
o Regenerate and retransmit data signals
o Maintain information about what pathways exist through the network and
internetwork
o Notify other devices of errors and communication failures
o Direct data along alternate pathways when there is a link failure
o Classify and direct messages according to QoS priorities
o Permit or deny the flow of data, based on security settings
 Examples of intermediary network devices are:
o Network Access Devices (Hubs, switches, and wireless access points)
o Internetworking Devices (routers)
o Communication Servers and Modems
o Security Devices (firewalls)
* What are the end devices? What are their functions?
 End devices are referred to as hosts.
o A host device is either the source or destination.
o A host can act as a client, a server, or both.
 Some examples of end devices are:
o Computers (work stations, laptops, file servers, web servers)
o Network printers
o VoIP phones
o Security cameras
o Mobile handheld devices (such as wireless barcode scanners, PDAs)
* What is LAN? What are the characteristics of LAN?



An individual network usually spans a single geographical area, providing
services and applications to people within a common organizational structure,
such as a single business, campus or region.
A LAN is usually administered by a single organization.
The administrative control that governs the security and access control
policies are enforced on the network level.
* What is WAN? What are the characteristics of WAN?
 When a company or organization has locations that are separated by large
geographical distances, it may be necessary to use a telecommunications
service provider (TSP) to interconnect the LANs at the different locations.
 These networks that connect LANs in geographically separated locations are
referred to as Wide Area Networks (WANs).
* What is the “multiplexing”?
 Sending smaller individual pieces from source to destination, many different
conversations can be interleaved on the network.
 The process used to interleave the pieces of separate conversations together
on the network is called multiplexing.
* What are the definitions of “network protocols”?
 define the structure of layer specific PDU's
 outline the functions necessary for communications between layers
 require layer dependent encapsulations
* Networking protocol suites describe processes such as:
 The format or structure of the message
 The method by which networking devices share information about pathways with
other networks
 How and when error and system messages are passed between devices
 The setup and termination of data transfer sessions
What are the functions of encapsulation?
 identifies pieces of data as part of the same communication
 ensures that data pieces can be directed to the correct receiving end device
 enables the reassembly of complete messages
* What is PDU?
 The form that a piece of data takes at any layer is called a Protocol Data Unit
(PDU).
 During encapsulation, each succeeding layer encapsulates the PDU that it
receives from the layer above in accordance with the protocol being used.
 At each stage of the process, a PDU has a different name to reflect its new
appearance.
o
o
o
o
o
Data - The general term for the PDU used at the Application layer
Segment - Transport Layer PDU
Packet - Internetwork Layer PDU
Frame - Network Access Layer PDU
Bits - A PDU used when physically transmitting data over the medium
* What is “encapsulation”? What are the purposes of encapsulation?
- Drippy Sweet Pancakes For Breakfast
- You need to know the name of each PDU during the encapsulation process.
- You need to know the information added to each stage.
* What is the purpose of the layer 4 (or transport layer) segment headers?
 The transport layer: The application data is broken into TCP segments.
o Each TCP segment is given a label, called a header, containing
information about which processes (or services) running on the destination
computer should receive the message.
* What is the purpose of the layer 3 (or internet layer, or network layer) packet headers?
 The Internet layer: Here the entire TCP segment is encapsulated within an IP
packet, which adds another label, called the IP header.
o The IP header contains source and destination IP addresses. .
* What is the purpose of the layer 2 (or network access layer, or data link layer) frame
headers and the trailers?
 The Network Access layer: Ethernet protocol where it is encapsulated within a
frame header and trailer.
o Frame header contains source and destination physical address.
o The trailer contains error checking information.
o Finally the bits are encoded onto the Ethernet media by the server NIC.
* What is “logical address”?
 Another name for logical address is IP address
* What is “physical address”?
 In a LAN using Ethernet, this address is called the Media Access Control (MAC)
address.
* You need to know the name of OSI models?
-Please Do Not Throw Sausage Pizza Away
- Can you list the primary function of each layer?
* You need to know the name of TCP/IP models?
-Never Ingest Tainted Apple
- Can you list the primary function of each layer?
* You need to know the side-by-side comparison of both models (which layer mapped to
which layer).
OSI
ISO Layer
Layer
Name
#
7
TCP/IP TCP/IP layer Encapsulation Devices or TCP/IP
Keywords/Description
#
Name
Units
Components Protocols
Application
(Away)
4
6
Presentation
(Pizza)
5
Session
(Sausage)
4
Transport
(Throw)
3
3
Network
(not)
2
2
Data Link
(DO)
1
1
Physical
(Please)
FTP,
HTTP,
POP3,
IMAP,
telnet, Network services for
SMTP, application processes, such as
DNS, file, print, messaging,
data
PC
TFTP database services
Application
Standard interface to data for
(Apple)
the application layer. MIME
encoding, data encryption,
conversion, formatting,
data
compression
Interhost communication.
Establishes, manages and
data
terminates connection
between applications
(Drippy)
TCP, End-to-end connections and
UDP reliability.
Segmentation/desegmentation
Transport segments
of data in proper sequence.
Flow control
(Tainted) (Sweet)
IP
Logical addressing and path
Internet
packets
determination. Routing.
Reporting delivery errors
(Ingest)
(Pancakes) router
Physical addressing and
access to media. Two
bridge,
sublayers: Logical Link
switch,
Control (LLC) and Media
Network frames
NIC
Access Control (MAC)
(For)
Access
(Never)
Binary transmission signals
repeater,
and encoding. Layout of pins,
bits
hub,
voltages, cable specifications,
modulation
(Breakfast) tranciever