CCNA Icnd110 s01l01

© 2007 Cisco Systems, Inc. All rights reserved. ICND1 v1.0—1-1
Building a Simple Network
Exploring the
Functions of
Networking

What Is a Network?

Common Physical Components of a
Network

Interpreting a Network Diagram

Resource-Sharing Functions and
Benefits
 Data and applications
 Resources
 Network storage
 Backup devices

Network User Applications
 E-mail (Outlook, POP3, Yahoo, and so on)
 Web browser (IE, Firefox, and so on)
 Instant messaging (Yahoo IM, Microsoft Messenger, and so on)
 Collaboration (Whiteboard, Netmeeting, WebEx, and so on)
 Databases (file servers)

Impact of User Applications on the
Network
 Batch applications
– FTP, TFTP, inventory updates
– No direct human interaction
– Bandwidth important, but not critical
 Interactive applications
– Inventory inquiries, database updates.
– Human-to-machine interaction.
– Because a human is waiting for a
response, response time is important
but not critical, unless the wait
becomes excessive.
 Real-time applications
– VoIP, video
– Human-to-human interaction
– End-to-end latency critical

Characteristics of a Network
 Speed
 Cost
 Security
 Availability
 Scalability
 Reliability
 Topology

Physical Topology Categories

Logical Topologies

Bus Topology
 All devices receive the signal.

Star Topology
 Transmission through a central point.
 Single point of failure.

Extended-Star Topology
 More resilient than star topology.

Ring Topology
 Signals travel around ring.
 Single point of failure.

Dual-Ring Topology
 Signals travel in opposite directions.
 More resilient than single ring.

Full-Mesh Topology
 Highly fault-tolerant
 Expensive to implement

Partial-Mesh Topology
 Trade-off between fault tolerance and cost

Connection to the Internet

Summary
 A network is a connected collection of devices that can
communicate with each other. Networks carry data in many kinds
of environments, including homes, small businesses, and large
enterprises.
 There are four major categories of physical components in a
computer network: the computer, interconnections, switches, and
routers.
 Networks are depicted graphically using a set of standard icons.
 The major resources that are shared in a computer network
include data and applications, peripherals, storage devices, and
backup devices.
 The most common network user applications include e-mail, web
browsers, instant messaging, collaboration, and databases.
 User applications affect the network by consuming network
resources.

 The ways in which networks can be described include
characteristics that address network performance and structure:
speed, cost, security, availability, scalability, reliability, and
topology.
 A physical topology describes the layout for wiring the physical
devices, while a logical topology describes how information flows
through a network.
 In a physical bus topology, a single cable effectively connects all
the devices.
 In a physical star topology, each device in the network is
connected to the central device with its own cable.
 When a star network is expanded to include additional networking
devices that are connected to the main networking device, it is
called an extended-star topology.
Summary (Cont.)

Summary (Cont.)
 In a ring topology, all the hosts are connected in the form of a ring
or circle. In a dual-ring topology, there are two rings to provide
redundancy in the network.
 A full-mesh topology connects all devices to each other; in a
partial-mesh topology, at least one device has multiple
connections to all other devices.
 There are three common methods of connecting the small office
to the Internet: DSL using the existing telephone lines, cable
using the CATV infrastructure, and serial links using the classic
digital local loops.

Practical questions
1. Which three statements about networks are
accurate? (Choose three.)
a) Networks are used to transmit data in many kinds of environments,
including homes, small businesses, and large enterprises.
b) A main office can have hundreds or even thousands of people who
depend on network access to do their jobs.
c) A network is a connected collection of devices that can communicate
with each other.
d) A main office usually has one large network to connect all users.
e) The purpose of a network is to create a means to provide all workers with
access to all information and components that are accessible by the
network.
f) Remote locations cannot connect to a main office through a network.

Answer
1. Which three statements about networks are
accurate? (Choose three.)
a) Networks are used to transmit data in many kinds of environments,
including homes, small businesses, and large enterprises.
b) A main office can have hundreds or even thousands of people who
depend on network access to do their jobs.
c) A network is a connected collection of devices that can
communicate with each other.
d) A main office usually has one large network to connect all users.
e) The purpose of a network is to create a means to provide all workers with
access to all information and components that are accessible by the
network.
f) Remote locations cannot connect to a main office through a network.

Practical questions
2. What is the purpose of a router?
a) To interconnect networks and choose the best paths between them
b) To provide the connection points for the media
c) To serve as the end point in the network, sending and receiving data
d) To provide the means by which the signals are transmitted from one
networked device to another

Answer
2. What is the purpose of a router?
a) To interconnect networks and choose the best paths between
them
b) To provide the connection points for the media
c) To serve as the end point in the network, sending and receiving data
d) To provide the means by which the signals are transmitted from one
networked device to another

Practical questions
3. What is the purpose of a switch?
a) to connect separate networks and filter the traffic over those networks
so that the data is transmitted through the most efficient route
b) to choose the path over which data is sent to its destination
c) to serve as the end point in the network, sending and receiving data
d) to provide network attachment to the end systems and intelligent
switching of the data within the local network

Answer
3. What is the purpose of a switch?
c) to serve as the end point in the network, sending and receiving data

Practical questions
4. What is the purpose of network interconnections?
c) to provide a means for data to travel from one point to another in the
network

Answer
4. What is the purpose of network interconnections?
a) to connect separate networks and filter the traffic over those
networks so that the data is transmitted through the most efficient
route
c) to provide a means for data to travel from one point to another in the
network

Practical questions
5. Which resource is not sharable on a network?
a) memory
b) applications
c) peripherals
d) storage devices

Answer
5. Which resource is not sharable on a network?
a) memory
b) applications
c) peripherals
d) storage devices

Practical questions
6. Which three of the following are common network
applications? (Choose three.)
a) e-mail
b) collaboration
c) graphics creation
d) database
e) word processing
f) spreadsheets

Answer
6. Which three of the following are common network
applications? (Choose three.)
a) e-mail
b) collaboration
c) graphics creation
d) database
e) word processing
f) spreadsheets

CCNA Icnd110 s01l01

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