Network Hardware.pdf

Network Hardware
9/13/2023 Compiled By : Sayed Ehsan Shamsi

What are networking Devices?
• Network devices are the devices used for
• organizing a network,
• connecting to a network,
• routing the packets,
• strengthening the signals,
• communicating with others,
• surfing the web,
• sharing files on the network and many more uses.

Types of network devices
• Modem
• Hub
• Switch
• NIC
• Repeater
• Bridge
• Router
• Gateway

Network Hardware's

Modem
• Modem stands for Modulation Demodulation.
• A modem converts data to a signal so it can be easily sent and
received over a phone line, cable, or satellite connection.
• For transmission over an analog telephone line—which was once the
most popular way to access the internet—the modem converts data
between analog and digital formats in real time for two-way network
communication.
• In the case of the high-speed digital modems popular today, the
signal is much simpler and doesn't require the analog-to-digital
conversion

Features of Modems
• They have high uploading and communication rates.
• An X2 modem provides an uploading bandwidth between 28.8 to 56
Kbps.
• Downstream data transfers rates of 33.6 kbps.
• Some modems combine dual simultaneous voice and Data (DSVD),
i.e., they can carry both analog voices and computer data.
• They can detect callers originating telephone number, and thus they
can serve as caller ID.

Types of Modems

Types of Modems
• Optical Modem
• Optical Modem uses optical cables instead of other metallic media. It converts the digital data signals into the
pulse of light transmitted on the optical fiber used by it.
• Digital Modem
• A digital modem converts digital data into digital signals. It modulates the digital data on the digital carrier
signals for transmission on digital transmission lines.
• Acoustic Modem
• The acoustic modem is a particular type of modem that can couple the telephone handset with a device used
by traveling salespeople to connect the hotel phones. It contains a speaker and microphone.
• Smart Modem
• The smart modem allows auto-dial/redial and auto-answer capabilities. It contains a microprocessor onboard
that uses the Hayes AT command set to provide auto-dial and auto answering functions.
• Short Haul Modem
• The short-haul modem is those who are present in your PC at home. They can transmit data over 20 miles or
less, and generally, they are used to connect PCs in a building or office within this area.

Modem Router
• Decodes the signal from an ISP.
• Connects directly to the internet.
• Doesn't set up a local network.
• Is not responsible for Wi-Fi.
• Establishes a local network.
• Creates and manages Wi-Fi.
• Splits an internet connection to several
devices.
• Does not decode the signal from an ISP.
• Requires a modem to connect to the internet.

Hub

What is the hub?
• A hub is a common connection point
• which is used for connection of devices in a network.
• It works as a central connection for all the devices that are connected
through a hub.
• The hub has numerous ports.
• If a packet reaches at one port, it is able to see by all the segments of the
network due to a packet is copied to the other ports.
• A network hub has no routing tables or intelligence (unlike a network
switch or router),
• which is used to send information and broadcast all network data across
each and every connection.

Hub
• Although most of the hubs can recognize network troubles or errors
like collisions, broadcasting all information to the several ports can be
a security risk and cause bottlenecks.
• The network hubs were popular in the past time as they were
cheaper as compared to a switch or router.
• Nowadays, switches are much cheaper than a hub and provide a
better solution for any network. Furthermore, a hub is no IP address,
as it is a dumb device

Types of Hub
There are three types of the hub
• Passive Hub:
• The passive hubs are the connection point for wires that helps to make the physical network.
• It is capable of determining the bugs and faulty hardware.
• Simply, it accepts the packet over a port and circulates it to all ports.
• Active Hub:
• it includes some additional features.
• It is able to monitor the data sent to the connected devices.
• It plays an important role between the connected devices with the help of store technology,
where it checks the data to be sent and decides which packet to send first.
• If a port receives a weak signal, but still it is readable, then the active hub reconstructs the
weak signal into a stronger signal before its sending to other ports.
• Intelligent Hub:
• It is a little smarter than passive and active hubs.
• These hubs have some kinds of management software that help to analyze the problem in
the network and resolve them.
• it offers better performance for the local area network.
• with any physical device, if any problem is detected, it is able to detect this problem easily.

• Features of Hub
• It acts with shared bandwidth and broadcasting.
• It includes only one collision domain and broadcast domain.
• It works at the physical layer of the OSI model and also offers support
for half-duplex transmission mode.
• It cannot create a virtual LAN
• Applications of Hub
• Hub is used to create small home networks.
• It is used for network monitoring.
• They are also used in organizations to provide connectivity.

• Advantages of Hub
• It can be used by anyone as it is very cheap.
• It can easily connect many different media types.
• The use of a hub does not impact on the network performance.
• Additionally, it can expand the total distance of the network.
• Disadvantages of Hub
• It has no ability to choose the best path of the network.
• It does not include mechanisms such as collision detection.
• It does not operate in full-duplex mode and cannot be divided into the Segment.
• It cannot reduce the network traffic as it has no mechanism.
• It is not able to filter the information as it transmits packets
• it is not capable of connecting various network architectures like a ring, token, and ethernet, and
more.

Hub Switch
A hub works at the physical layer of the OSI
model.
A switch works at the data link layer of the OSI model.
A hub contains a single domain of collision. In switch, several ports include separate collision
domains.
It performs frame flooding, which can be
broadcast, unicast, or multicast.
It mainly performs broadcast, and also performs unicast
and multicast when required.
In the hub, the transmission mode is Half-
duplex
In switch, the transmission mode is full-duplex.
It uses electrical signal orbits. It uses frame & packet.
It does not support the Spanning-Tree
protocol.
It supports Multiple Spanning-Tree.
In the hub, mostly collisions occur in setup. In full-duplex switch does not occur collisions.
It is a passive device. It is an active device.
A hub is not capable of storing MAC
addresses.
It uses accessible content memory, which can be
accessed by application-specific integrated chips
(ASIC).
It is not an intelligent device. A switch is an intelligent device.
The speed of the hub network is up to 10 Mb
per second.
The speed of switch is 10/100 Mbps, 1 Gbps, and 10
Gbps.
Difference between hub and switch

HUB

What are the Repeaters
• A repeater is a dynamic network device
• used to reproduce the signals when they transmit over a greater
distance so that the signal’s strength remains equal.
• It can be used to create an Ethernet network.
• A repeater that occurs as the first layer of the OSI layer is the physical
layer.

Repeater

Features of Repeaters
• repeaters are linked to each other at the physical layer.
• It sends the signals for the unsteady areas to enlarge the system signals.
• These receptors linked the various network signals to convert the data
between the two devices.
• These repeaters can eliminate the distance between the two devices.
• The repeaters can frequently monitor the signals that are created between
the two LANs.
• The IP network links all the repeaters with an IP site relation network.
• These receptors can support 100 % digital communication so that they do
not require to wait for analog voice calls.

• Advantages of Repeater
• The signals get weaker as they transit to greater distances. The repeater provides the
stability of the signals.
• These repeaters are cost-effective and easy to use.
• The repeaters don’t influence network performance.
• These repeaters can retransmit the information and powerful the weak signals.
• Disadvantage of Repeaters
• They cannot connect two distinct networks.
• While amplifying the signals, the repeaters also amplify the level of noise in those
signals.
• If we enhance the extent of the web by only using the repeaters. In that case, the signal
propagation time will grow to a considerable level, and the network’s performance will
collapse.

Bridge in Computer Network?
• A bridge is a network device that connects two or more LANs (local
area networks) to form a larger LAN.
• Network bridging refers to the process of aggregating networks.
• A bridge connects the various components, making them appear to
be part of a single network.
• In the OSI model, a bridge operates at layer 2, or the data link layer.
• This is primarily to check incoming traffic and determine whether it
should be filtered or forwarded.

Working of Bridge
• A bridge accepts all packets and amplifies them before sending them
to the other side.
• Bridges are intelligent devices that allow only specific packets to pass
through them.
• A bridge only transmits packets addressed from one network node to
another

Types of Bridges in Computer Networks
• Transparent Bridge
• It's an invisible computer network bridge, as the name implies.
• This bridge's primary function is to block or forward data based on
the MAC address.
• The other devices in the network are entirely unaware that bridges
exist.
• This bridge keeps MAC addresses in a table similar to a routing table.
• Typically, these bridges are used in Ethernet networks.

Source-Route Bridge
• It decides the route between two hosts.
• The entire frame route is contained within a single frame in this bridge.
• The data link layer is connected to two similar network using this method.
Translational bridge
• Translational bridges are a type of network bridge that can translate
between various network protocols.
• This enables devices on different networks to communicate with one
another, even if they are using different protocols.
• It can connect different types of networks and helps in improving network
security and performance.

Uses of Bridge in Computer Network
• Bridges are used to divide large networks into smaller groups,
networks which helps to reduce traffic.
• Bridges are used to extend the range of the network by connecting
two or more physically separated segments.
• Bridges provide security as it separates different parts of networks
from each other.
• Bridges provide network redundancy by connecting two or more
paths between different network segments.
• Bridges are used to forward frames without changing the source or
destination

Advantages of Bridges in Computer Networks Disadvantages of Bridges in Computer
Networks
• It serves as a network extender by acting as
a repeater.
• Subdividing network traffic into network
communications can reduce network traffic
on a segment.
• Collisions can be reduced to a minimum.
• Some types of bridges use architectures
and different types of media to connect
networks.
• Because fewer network nodes share a
collision domain, bridges increase the
available bandwidth to individual nodes.
• It reduces BW waste (bandwidth).
• The network's length can be extended.
• It connects various network transmission
segments.
• It cannot assist in the construction of the
network between the various network
architectures.
• Because it is more concerned with MAC
addresses, it cannot read specific IP
addresses.
• When compared to repeaters, these are
more expensive.
• It cannot stop the flow of messages
because it transmits all types of broadcast
messages.
• It can't handle the more variable and
complex data loads from the WAN.

Bridge

Switches in Computer Networks
• Switches are networking devices operating at layer 2 or a data link
layer of the OSI model.
• They connect devices in a network and use packet switching to send,
receive or forward data packets or data frames over the network.
• A switch has many ports, to which computers are plugged in.
• When a data frame arrives at any port of a network switch, it
examines the destination address, performs necessary checks and
sends the frame to the corresponding device(s).
• It supports unicast, multicast as well as broadcast communications

Switches

Features of Switches
• It is an intelligent network device that can be conceived as a multiport network bridge.
• It uses MAC addresses to send data packets to selected destination ports.
• It uses packet switching technique to receive and forward data packets from the source
to the destination device.
• It is supports unicast (one-to-one), multicast (one-to-many) and broadcast (one-to-all)
communications.
• Transmission mode is full duplex, i.e. communication in the channel occurs in both the
directions at the same time. Due to this, collisions do not occur.
• Switches are active devices, equipped with network software and network management
capabilities.
• Switches can perform some error checking before forwarding data to the destined port.
• The number of ports is higher – 24/48.

Types of Switches
• Switches are categorized into 4 types:
Unmanaged Switch −
• These are inexpensive switches commonly used in home networks
and small businesses.
• They can be set up by simply plugging in to the network, after which
they instantly start operating.
• When more devices needs to be added, more switches are simply
added by this plug and play method.
• they do not require to be configured or monitored.

Managed Switch −
• These are costly switches that are used in organizations with large and
complex networks, since they can be customized to augment the
functionalities of a standard switch.
• The augmented features may be QoS (Quality of Service) like higher
security levels, better precision control and complete network
management.
• Despite their cost, they are preferred in growing organizations due to their
scalability and flexibility.
• Simple Network Management Protocol (SNMP) is used for configuring
managed switches.

• LAN Switch − Local Area Network (LAN) switches connects devices in
the internal LAN of an organization.
• They are also referred as Ethernet switches or data switches.
• These switches are particularly helpful in reducing network
congestion or bottlenecks.
• They allocate bandwidth in a manner so that there is no overlapping
of data packets in a network.

• PoE Switch − Power over Ethernet (PoE) switches are used in PoE
Gogabit Ethernets. PoE technology combine data and power
transmission over the same cable so that devices connected to it can
receive both electricity as well as data over the same line. PoE
switches offer greater flexibility and simplifies the cabling connections

How Does a Network Switch Works?
• When the source wants to send the data packet to the destination,
the packet first enters the switch and the switch reads its header and
finds the MAC address of the destination to identify the device then it
sends the packet out through the appropriate ports that lead to the
destination devices.
• Switch establishes a temporary connection between the source and
destination for communication and terminates the connection once
the conversation is done. Also, it offers full bandwidth to network
traffic going to and from a device simultaneously to reduce collision.

Network Switch Router
Network Switch works on Layer 2 of the OSI Model.
The router is primarily a device of Layer 3 of the OSI
Model.
The resource is shared among multiple devices with
the help of a single LAN using a network switch.
Data is moved between two or more computers with
the help of a router.
Network switches uses data frames. Routers use data packets.
Switches only work in a Wired network connection. Router works with both wired and wifi networks.
Switches use MAC Addresses for transferring data to
the proper destination.
Routers use IP Addresses for the same work.

• Advantages of Switches
• Prevents traffic overloading in a network by segmenting the network
into smaller subnets.
• Increases the bandwidth of the network.
• Less frame collision as the switch creates the collision domain for
each connection.
• Disadvantages of Switches
• It can not stop traffic destined for a different LAN segment from
traveling to all other LAN segments.
• Switches are more expensive.

What is a Router?
• The router is a physical or virtual internetworking device that is designed to receive,
analyze, and forward data packets between computer networks.
• A router examines a destination IP address of a given data packet, and it uses the
headers and forwarding tables to decide the best way to transfer the packets.
• There are some popular companies that develop routers; such
are Cisco, 3Com, HP, Juniper, D-Link, Nortel, etc.
• Some important points of routers are given below:
• A router is used in LAN (Local Area Network) and WAN (Wide Area Network)
environments.
• For example, it is used in offices for connectivity, and you can also establish the
connection between distant networks
• It shares information with other routers in networking.
• It uses the routing protocol to transfer the data across a network.
• Furthermore, it is more expensive than other networking devices like switches and hubs

Router
• A router works on the third layer of the OSI model,
• it is based on the IP address of a computer.
• It uses protocols such as ICMP to communicate between two or more
networks.
• It is also known as an intelligent device as it can calculate the best
route to pass the network packets from source to the destination
automatically.

Why Routers?
• A router is more capable as compared to other network devices, such
as a hub, switch, etc., as these devices are only able to execute the
basic functions of the network.
• For example, a hub is a basic networking device that is mainly used to
forward the data between connected devices, but it cannot analyze or
change anything with the transferring data.
• On the other hand, the router has the capability to analyze and
modify the data while transferring it over a network, and it can send it
to another network.
• For example, generally, routers allow sharing a single network
connection between multiple devices.

How does Router work?
• A router analyzes a destination IP address of a given packet header
and compares it with the routing table to decide the packet's next
path. The list of routing tables provides directions to transfer the data
to a particular network destination. They have a set of rules that
compute the best path to forward the data to the given IP address.
• Routers use a modem such as a cable, fiber, or DSL modem to allow
communication between other devices and the internet. Most of the
routers have several ports to connect different devices to the internet
at the same time. It uses the routing tables to determine where to
send data and from where the traffic is coming

• A routing table mainly defines the default path used by the router. So,
it may fail to find the best way to forward the data for a given packet.
For example, the office router along a single default path instructs all
networks to its internet services provider.
• There are two types of tables in the router that are static and
dynamic. The static routing tables are configured manually, and the
dynamic routing tables are updated automatically by dynamic routers
based on network activity

Features of Router
• A router works on the 3rd layer (Network Layer) of the OSI model, and it is able to communicate
with its adjacent devices with the help of IP addresses and subnet.
• A router provides high-speed internet connectivity with the different types of ports like gigabit,
fast-Ethernet, and STM link port.
• It allows the users to configure the port as per their requirements in the network.
• Routers' main components are central processing unit (CPU), flash memory, RAM, Non-Volatile
RAM, console, network, and interface card.
• Routers are capable of routing the traffic in a large networking system by considering the sub-
network as an intact network.
• Routers filter out the unwanted interference, as well as carry out the data encapsulation and
decapsulation process.
• Routers provide the redundancy as it always works in master and slave mode.
• It allows the users to connect several LAN and WAN.
• Furthermore, a router creates various paths to forward the data.

• Applications of Routers
• There are various areas where a router is used:
• Routers are used to connect hardware equipment with remote location networks like BSC, MGW, IN, SGSN, and other servers.
• It provides support for a fast rate of data transmission because it uses high STM links for connectivity; that's why it is used in both
wired or wireless communication.
• Internet service providers widely use routers to send the data from source to destination in the form of e-mail, a web page, image,
voice, or a video file. Furthermore, it can send data all over the world with the help of an IP address of the destination.
• Routers offer access restrictions. It can be configured in a way that allows for few users to access the overall data and allows others
to access the few data only, which is defined for them.
• Routers are also used by software testers for WAN communications. For example, the software manager of an organization is
located in Agra, and its executive is located at a different place like Pune or Bangalore. Then the router provides the executive the
method to share his software tools and other applications with the manager with the help of routers by connecting their PCs to
the router using WAN architecture.
• In wireless networks, by configuring VPN in routers, it can be used in the client-server model, which allows sharing the internet,
video, data, voice, and hardware resources. As shown in the below picture:
•

• In modern times, routers have the facility of inbuilt USB ports within
the hardware. They have enough internal storage capacity. External
storage devices can be used with routers to store and share data.
• Routers are used to set up the operation and maintenance center of
an organization, which is known as the NOC center. All equipment at a
distant location are connected by routers on optical cable at a central
location, which also offer redundancy through the main link and
protection link topology

• Types of Routers
• There are various types of routers in networking; such are given below:
• 1. Wireless Router: Wireless routers are used to offer Wi-Fi connectivity to
laptops, smartphones, and other devices with Wi-Fi network capabilities, and it
can also provide standard ethernet routing for a small number of wired network
systems.
• Wireless routers are capable of generating a wireless signal in your home or
office, and it allows the computers to connect with routers within a range, and
use the internet. If the connection is indoors, the range of the wireless router is
about 150 feet, and when the connection is outdoors, then its range is up to 300
feet.
• Furthermore, you can make more secure wireless routers with a password or get
your IP address. Thereafter, you can log in to your router by using a user ID and
password that will come with your router.

• 2. Brouter: A brouter is a combination of the bridge and a router. It allows transferring the data between networks like a bridge.
And like a router, it can also route the data within a network to the individual systems. Thus, it combines these two functions of
bridge and router by routing some incoming data to the correct systems while transferring the other data to another network.
• 3. Core router: A core router is a type of router that can route the data within a network, but it is not able to route the data
between the networks. It is a computer communication system device and the backbone of networks, as it helps to link all
network devices. It is used by internet service providers (ISPs), and it also provides various types of fast and powerful data
communication interfaces.
• 4. Edge router: An edge router is a lower-capacity device that is placed at the boundary of a network. It allows an internal network
to connect with the external networks. It is also called as an access router. It uses an External BGP (Border Gateway Protocol) to
provides connectivity with remote networks over the internet.
• There are two types of edge routers in networking:
• Subscriber edge router
• Label edge router
• The subscriber edge router belongs to an end-user organization, and it works in a situation where it acts on a border device.
• The label edge router is used in the boundary of Multiprotocol Label Switching (MPLS) networks. It acts as a gateway between the
LAN, WAN, or the internet.

• 5. Broadband routers: Broadband routers are mainly used to provide
high-speed internet access to computers. It is needed when you
connect to the internet through phone and use voice over IP
technology (VOIP).
• All broadband routers have the option of three or four Ethernet ports
for connecting the laptop and desktop systems. A broadband router is
configured and provided by the internet service provider (ISP). It is
also known as a broadband modem, asymmetric digital subscriber
line (ADSL), or digital subscriber line (DSL) modem

• Routing Protocols
• Routing protocols specify a way for the router to identify other routers on
the network and make dynamic decisions to send all network messages.
There are several protocols, which are given below:
• Open Shortest Path First (OSPF): It is used to calculate the best route for
the given packets to reach the destination, as they move via a set of
connected networks. It is identified by the Internet Engineering Task
Force (IETF) as Interior Gateway Protocol.
• Border Gateway Protocol (BGP): It helps manage how packets are routed
on the internet via exchange of information between edge routers. It
provides network stability for routers if one internet connection goes down
while forwarding the packets, it can adapt another network connection
quickly to send the packets.

• Interior Gateway Routing Protocol (IGRP): It specifies how routing information will be
exchanged between gateways within an independent network. Then, the other network
protocols can use the routing information to determine how transmissions should be
routed.
• Enhanced Interior Gateway Routing Protocol (EIGRP): In this protocol, if a router is
unable to find a path to a destination from the tables, it asks route to its neighbors, and
they pass the query to their neighbors until a router has found the path. When the entry
of routing table changes in one of the routers, it informs its neighbors only about the
changes, but do not send the entire table.
• Exterior Gateway Protocol (EGP): It decides how routing information can be exchanged
between two neighbor gateway hosts, each of which has its own router. Additionally, it is
commonly used to exchange routing table information between hosts on the internet.
• Routing Information Protocol (RIP): It determines how routers can share information
while transferring traffic among connected group of local area networks. The maximum
number of hops that can be allowed for RIP is 15, which restricts the size of networks
that RIP can support.

Bridge Router
A bridge is a networking device that is used to
connect two local area networks (LANs) by
using media access control addresses and
transmit the data between them.
A router is also a networking device that sends
the data from one network to another network
with the help of their IP addresses.
A bridge is able to connect only two different
LAN segments.
A router is capable of connecting the LAN and
WAN.
A bridge transfers the data in the form of
frames.
A router transfers the data in the form of
packets.
It sends data based on the MAC address of a
device.
It sends data based on the IP address of a
device.
The bridge has only one port to connect the
device.
The router has several ports to connect the
devices.
The bridge does not use any table to forward
the data.
The router uses a routing table to send the
data.

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