2. Networking Devices
As these devices connect network entities, they’re known as connectivity devices.
1. Hub
2. Repeater
3. Modem
4. Network Interface Card (NIC)
5. Bridge
6. Basic Switch
7. Wireless access point (AP)
8. Basic router
9. Basic firewall
10. Basic Dynamic Host Configuration Protocol
3. The Hub
A hub is the device that connects all the segments of the network together in a star topology
Ethernet network. Every device in the network connects directly to the hub through a single
cable and is used to connect multiple devices without segmenting a network.
Any transmission received on one port will be sent out all the other ports in the hub,
including the receiving pair for the transmitting device, so that Carrier Sense Multiple Access
with Collision Detection (CSMA/CD) on the transmitter can monitor for collisions.
5. The Repeater
Figure below shows a repeater being used to connect two unshielded twisted-pair
(UTP) connectors. This configuration will provide an extension to your Ethernet
segment and give you a gain of another 100 meters (328 feet).
6. The modem
A modem is a device that modulates digital data onto an analog carrier for transmission
over an analog medium and then demodulates from the analog carrier to a digital signal
again at the receiving end. The term modem is actually an acronym that stands for
MOdulator/DEModulator.
When you hear the term modem, three different types should come to mind:
Traditional (plain old telephone service [POTS])
DSL
Cable
8. 1. Network Interface Card (NIC):- A network Interface Card (NIC) is installed in
computer to connect, or interface, computer to the network. It provides the physical,
electrical, and electronic connections to the network media. Figure below shows a
typical 100Mbps Ethernet NIC.
9. The bridge
A bridge—specifically, a transparent bridge—is a network device that connects two
similar network segments together. Its primary function is to keep traffic separated on
either side of the bridge, breaking up collision domains, as pictured in Figure below.
10. The switches
Switches: - Switches connect multiple segments of a network together much like hubs
do, but with three significant differences—a switch recognizes frames and pays attention
to the source and destination MAC address of the incoming frame as well as the port on
which it was received.
11. Wireless Access Point (AP)
A wireless access point (AP) is a networking device that creates a wireless
local area network (WLAN), usually in an office or large building. It connects
to a wired router, switch, or hub via an Ethernet cable and projects a WiFi
signal to a designated area.
12. The router
router is a networking device that forwards data packets between computer
networks. It is a core component of the internet infrastructure and plays a crucial
role in connecting devices, enabling communication, and routing data traffic
efficiently.
Key Functions of a Router:
Packet Forwarding: Routers analyze the destination addresses of data packets and
determine the best path to forward the packets to their intended destinations. They
maintain routing tables that map network addresses to physical connections, ensuring
seamless data transfer across different networks.
Data Routing: Routers identify the most efficient routes for data packets to travel,
considering factors like network congestion, path length, and link quality. This
optimization minimizes latency and ensures high-performance data transmission.
13. The router
Firewall: Routers often incorporate firewall capabilities, acting as gatekeepers that filter
and control incoming and outgoing network traffic. This protection safeguards networks
from unauthorized access, malicious attacks, and data loss.
Wireless Connectivity: Routers commonly provide wireless access points (WAPs),
enabling devices to connect to the network without cables. This flexibility allows for
mobility and convenient internet access for multiple devices.
Routers in Different Network Environments:
Home Networks: Residential routers connect computers, smartphones, and smart devices
within a home, providing internet access and enabling data sharing.
Business Networks: Enterprise routers manage large-scale networks, connecting devices
within offices, retail establishments, and industrial facilities. They handle high data
traffic volumes and support various network protocols.
Internet Service Providers (ISPs): Core routers at ISPs connect multiple networks,
routing traffic between them and ensuring efficient data transmission across the internet
backbone.
14. The router
Role of Routers in the Internet Infrastructure:
Data Exchange: Routers facilitate data exchange between different networks, enabling
communication and collaboration across the internet.
Content Delivery: Routers play a critical role in content delivery, routing data packets
from content providers to users worldwide.
Network Resilience: Routers provide redundancy and load balancing, ensuring network
stability and preventing service disruptions during peak usage or network failures.
15. The firewall
Types of Firewalls:
Packet-filtering firewalls: These firewalls inspect each packet individually and allow or
deny it based on its source and destination addresses, port numbers, and protocol types.
Stateful inspection firewalls: These firewalls track the state of network connections and
only allow traffic that is part of an established connection. This provides more granular
control over network traffic and helps to prevent intrusion attempts.
Deep packet inspection (DPI) firewalls: These firewalls analyze the contents of
network packets to identify and block malicious traffic, such as spam, malware, and
phishing attacks.
16. The firewall
Functions of Firewalls:
Protecting against unauthorized access: Firewalls can prevent unauthorized users
from accessing the network. This includes both external attackers and internal
users who do not have the proper permissions.
Protecting against malicious attacks: Firewalls can block malicious traffic, such as
malware, viruses, and worms, from entering the network.
Protecting against data breaches: Firewalls can help to prevent data breaches by
limiting the types of traffic that can enter or leave the network.
17. Dynamic Host Configuration Protocol
The Dynamic Host Configuration Protocol (DHCP) is a network protocol that
automatically assigns IP addresses and other configuration parameters to devices on a
network. This eliminates the need for manual configuration of IP addresses, subnets,
default gateways, and other parameters. DHCP is a client-server protocol, in which a
DHCP server maintains a pool of IP addresses and leases them out to DHCP clients.
![The modem
A modem is a device that modulates digital data onto an analog carrier for transmission
over an analog medium and then demodulates from the analog carrier to a digital signal
again at the receiving end. The term modem is actually an acronym that stands for
MOdulator/DEModulator.
When you hear the term modem, three different types should come to mind:
Traditional (plain old telephone service [POTS])
DSL
Cable](https://image.slidesharecdn.com/cp102chapter03commonnetwork-250405170458-ef9f7720/85/CP102_Chapter03_Common_Netwojrk-in-basic-6-320.jpg)
