Chapter one

Network Device Configuration

Configuration Wizard
Quiz 5%
• What is network Device configuration and why we
need to configure?

• What we mean by Encapsulation of Data on Network

and how OSI layer encapsulation steps taken by each
layers?

• Why Data Framing is needed and How can we

frame?
• VLANs (Virtual LANs) are logical grouping of devices in the
same broadcast domain. VLANs are usually configured on
switches by placing some interfaces into one broadcast domain
and some interfaces into another. Each VLAN acts as a
subgroup of the switch ports in an Ethernet LAN
Configuration Wizard
• While the configuration wizard is an easy way to display complex
configuration options,
• it does rely on the user having a basic understanding of the software
component.
• Network configuration is a process that involves the assignment of
network configurations, rules, controls, and flows. The configuration
of a switch or router, the configuration of a host, the setup of software
and a firewall, and the creation of a network architecture that can be
managed using rest APIs are some of the fundamentals of network
configuration.
Cont…

• The ability to configure a network provides a system administrator the ability to

set up a network to satisfy certain communication goals. The following activities
are included in the process:
• Configuration of the router includes specifying the appropriate IP addresses and
route settings, among other things.
• Host setup is the process of enabling a network connection and communication on
a host computer or laptop by recording the default network settings. These settings
include IP addressing, proxy, network name, and ID/password.
• Software configuration: To monitor network traffic, any network-based software,
such as an intrusion detection system (IDS), is granted access and given the proper
credentials.
• In addition, network setup involves the sharing of the Internet and the local area
network, the installation of software and applications, and the installation and
configuration of a firewall.
 Introduction
• When we think of connectivity in a network, the router is probably the
first device that comes to mind,
• but switches play a vital role in enabling network devices to
communicate.
• Switches can take incoming/outgoing traffic and pass it onward
toward its final destination.
Introduction
• In a networked environment, computers connected together using a
router or a switch.
• In larger companies, there may be several different routers distributed in
buildings and plant locations.
• A router allows any LAN-side computer communicate with computers
and devices outside the LAN.
• Routers send data packets from one place to another place on a network.
• Routers use network addresses to route packets to the correct destination.
• For example, in a TCP/IP network, the IP address of the network
interface is used to direct router destinations.
Network Devices
Router
• A router is a device that forward data packets over networks.
• Most commonly, a router is connected to at least two networks (normally LANs or WANs).
• Routers are located at gateways, the place where two networks are connected.
• Routers do little data filtering, they mainly deliver the data.
Switch
• A switch is a device that filters and forwards data packets between networks.
• Switches operate at the data layer, and sometimes at the network layer.
 Subnet
• A subnet is a portion of a network that shares a common address component.
• On a TCP/IP network, a subnet is described as all computers or devices whose IP Address have
the same prefix.
• Subnetting a network is useful because it provides security for the network as well as increases
performance of the network.
• IP networks are divided using subnet masks.
General view
CLI Configuration Modes
The basic CLI modes that we will be referring below are as following:
CLI is essential for more complex configuration tasks and it is the most
important knowledge
Router> <– User EXEC Mode
Router# <– Privileged EXEC mode
Router(config)# <– Global Configuration Mode
Router(config-if)# <– Interface Configuration Mode
Router(config-line)# <– Line Configuration Mode
In Global Configuration Mode you configure parameters that affect the
whole router device.
 Cont…
• two Router Configuration Modes (or access modes):
• User EXEC Mode: Allows the administrator to access only limited
monitoring commands. You can not actually make any configurations
from this mode. The command prompt on this mode is “router>”
• Privileged EXEC Mode: Allows the administrator to access all device
commands, such as those used for configuration and management,
and can be password protected to allow only authorized users to
access the device at this “full-access” level. This mode is also called
enable mode because you get to it with the enable command. The
command prompt on this mode is “router#”. From the privileged
EXEC mode you can start configuring the device by typing “configure
terminal“.
 Cont…
• Global Configuration Mode: enable us to configure the terminals and
changes can be happen here{Host name, Domain name, create an
account} e.g Router(config)#
• Interface Configuration Mode: allows us to give an IP address to
interface. e.g Router(config-if)#
• Line Configuration Mode: enhance the network administrator to
protect the accessibility to only the authorized user only by giving the
password and protect unauthorized access. e.g Router(config-line)#
Router Memory Types
A Cisco router has four memory types:
• ROM: This is where the POST script of the router is located. The POST software (Power
On Self Test) is used during startup to perform the initial hardware checking of the
device. The ROM also holds a mini-IOS used for password recovery.
• RAM: This is where the running configuration is located. After the device boots up, the
IOS software is loaded into RAM. Also, RAM holds routing tables, network parameters
during operation etc. When configuring the router, we actually change the running-
configuration which as we said is stored into RAM
• NVRAM: When we save the running-configuration (using the command “write“) it is
stored into the NVRAM and becomes the startup-configuration. After rebooting the
router, the startup-configuration is loaded from the NVRAM.
• Flash: This is like the hard-disk of a PC. It holds the IOS software image file and any
backup configurations that we might save from time to time.
• When we issue the “show running-configuration” command on the router we instruct
the device to display the current running configuration in RAM.
• When we issue the “show startup-configuration” command we instruct the router to
display the stored configuration in the NVRAM.