5 Networking Fundamentals

Question 1

Six types of networks:

Answer 1

Local area network (LAN)
Wide area network (WAN)
Personal area network (PAN)
Metropolitan area network (MAN)
Storage area network (SAN)
Wireless local area network (WLAN)

Question 2

What is LAN ?

Answer 2

LANs (local area network) simply link computers in order to share resources within a closed environment.

Question 3

What is (WAN) ?

Answer 3

A wide area network (WAN) . Whereas LANs are limited to single buildings, WANs can span buildings, states, countries, and even continental boundaries. It’s safe to think of a WAN as multiple dispersed LANs connected
together.

Question 4

What is PAN ?

Answer 4

Personal Area Networks (PANs) used in reference to Bluetooth networks.

wireless personal area network (WPAN)

Whenever two Bluetooth devices get close enough to each other, they can communicate directly with each other—no central communication point is required. This dynamically created network is called a
piconet. A Bluetooth-enabled device can communicate with up to seven other devices in one piconet. Two or more piconets can be linked together in a scatternet. In a scatternet, one or more devices would serve as a bridge between the piconets.

Question 5

What is a MAN ?

Answer 5

Metropolitan Area Networks (MAN). For those networks that are larger than a LAN but confined to a relatively small
geographical area, there is the term metropolitan area network (MAN). A MAN is generally defined as a network that spans a city or a large campus. For example, if a city decides to install wireless hotspots in various places, that network could be considered a MAN. The difference between MAN and WAN is who has responsibility for managing the connectivity.

In a MAN, a central IT organization, such as the campus or city IT staff, is responsible. In a WAN, it’s implied that you will be using publicly available communication lines, and there will be a phone company or other service provider involved.

Question 6

What is a SAN ?

Answer 6

A storage area network (SAN) is designed to do exactly what it says, which is to store
information. This network won’t have client computers or other types of servers on it.
It’s for storage only.

Question 7

Denefits to SAN:

Answer 7

Dedicated SANs relieve network loads. With a SAN, all storage traffic, which may
include huge data files or videos, is sent to a specific network or network segment,
relieving traffic on other network segments.

SANs offer fast data access. Most SANs use high-speed Fibre Channel connections,
which allow for very fast access even for huge files.

SANs are easily expandable. In most cases, it’s a matter of connecting a new storage
unit, which might even be hot-swappable
(removed and replaced without powering
down the system), and a few clicks to configure it. Then it’s ready to go.

Block-level storage is more efficient. Most
SANs are configured to store and retrieve data in a system called block storage. This
contrasts with the file-based access systems you’re probably used to, such as the ones in Windows and macOS.

Block storage allows a file to be broken into more manageable chunks rather than
being stored as one entity. This allows the operating system to modify one portion of
a file without needing to open the entire file. In addition, since data reads and writes
are always of the same block size, data transfers are more efficient and therefore faster. Latency with block storage is lower than with other types of storage.

Question 8

What is WLAN ?

Answer 8

A wireless local area network (WLAN) is simply a LAN, but one in which clients connect wirelessly rather than through
network cables.

Wireless clients on a network typically access the network through a wireless access point
(WAP). The WAP may connect wirelessly to another connectivity device, such as a wireless router, but more likely uses a wired connection to a router or switch.

Question 9

Primary Network Components:

Answer 9

Servers
Clients or workstations
Resources

Every network requires two more items to tie these three components together: a network operating system (NOS) and some kind of shared medium (wired or wireless connectivity).

Question 10

What are Servers ?

Answer 10

They provide a link to the resources necessary to perform any task. The link that the server provides could be to a resource existing on the server itself or to a resource on a client computer.

Servers offer networks the capability of centralizing the control of resources and security, thereby reducing administrative difficulties. They can be used to distribute processes for balancing the load on computers and can thus increase speed and performance. They can also compartmentalize files for improved reliability. That way, if one server goes down, not all of the files are lost. Servers can perform several different critical roles on a network. For example, a server that provides files to the users on the network is called a file server. Likewise, one that hosts printing services for users is called a print server. Servers can be used for other tasks as well, such as authentication, remote access services, administration, email, and so on.

Networks can include multipurpose and single-purpose servers. A multipurpose server can be, for example, both a file server and a print server at the same time. If the server is a single-purpose server, it is a file server only or a print server only.

Question 11

What is a dedicated server ?

Answer 11

A dedicated server is assigned to provide specific applications or services for the network and nothing else. Because a dedicated server specializes in only
a few tasks, it requires fewer resources than a nondedicated server might require from
the computer that is hosting it. This savings may translate to efficiency and can thus be
considered as having a beneficial impact on network performance. A web server is an
example of a dedicated server; it is dedicated to the task of serving up web pages and
nothing else.

Question 12

What is a non-dedicated server ?

Answer 12

Nondedicated servers are assigned to provide one or more network services and local access. Nondedicated servers can be used to direct network traffic and perform administrative actions, but they also are often used to serve as a frontend for the administrator to work with other applications or services or to perform services for more than one network. For example, a dedicated web server
might serve out one or more websites, whereas a nondedicated web server serves out websites but might also function as a print server on the local network or as the administrator’s workstation.

Question 13

What are workstations ?

Answer 13

Workstations are the computers on which the network users do their work, performing
activities such as word processing, database design, graphic design, email, and other office or personal tasks. A workstation is basically an everyday computer, except for the fact that it is connected to a network that offers additional resources. In network terms, workstations are also known as client computers. As clients, they are allowed to communicate with the servers in the network to use the network’s resources.

Question 14

What are network resources ?

Answer 14

Printers and other peripherals
Disk storage and file access
Applications

Question 15

What are Network Operating Systems ?

Answer 15

Network Operating Systems PCs use a disk operating system that controls the filesystem and how the applications communicate
with the hard disk. Networks use a network operating system (NOS) to control the communication with resources and the flow of data across the network. The NOS runs
on the server. Some of the more popular NOSs are Linux, Microsoft’s Windows Server series (Server 2022, Server 2019, and so on), and macOS Server.

Question 16

Two resource access models:

Answer 16

peer-to-peer

client-server

Question 17

Peer to Peer:

Answer 17

In a peer-to-peer network (referred to as workgroups), the computers act as both service providers and service requestors.

The peer-to-peer model is great for small, simple, inexpensive networks. This model can be set up almost instantly, with little extra hardware required. Generally speaking, there is no centralized administration or control in the peer-to-peer
resource model. Every workstation has unique control over the resources that the computer owns, and each workstation must be administered separately. However, this lack of centralized control can make administering the network difficult; for the same reason, the network isn’t very secure. Each user needs to manage separate passwords for each computer on which they wish to access resources, as well as set up and manage the shared resources on
their own computer. It may not be easy to locate resources. The person who is in charge of a file may have moved it without anyone’s knowledge. Also, the users who work under this arrangement need more training because they are not only users but also administrators.

Question 18

Client-Server:

Answer 18

Client-Server Resource Model (also known as server-based model) is better than the peer to-peer model for large networks (more than 10 computers) that need a more secure environment and centralized control. Server-based networks use one or more dedicated, centralized servers. All administrative functions and resource sharing are performed from this point. This makes it easier to share resources, perform backups, and support an almost unlimited number of users. This model also offers better security than the peer-to-peer model. However, the server needs more hardware. In addition, it requires specialized software (the NOS) to manage the server’s role in the environment. With the addition of a server and the NOS, server-based networks can easily cost more than peer-to-peer resource models. However, for large networks, it’s the only
choice.

Question 19

5 Network Topologies:

Answer 19

Bus
Cheap. Easy to install.
Difficult to reconfigure. A break in the bus disables the entire network.

Star
Cheap. Very easy to install and reconfigure.
More resilient to a single cable failure.
More expensive than bus.

Ring
Efficient. Easy to install.
Reconfiguration is difficult. Very expensive.

Mesh
Best fault tolerance.
Reconfiguration is extremely difficult,
extremely expensive, and very complex.

Hybrid
Gives a combination of the best features
of each topology used.
Complex (less so than mesh, however).

Question 20

Bus Topology:

Answer 20

A bus topology is the simplest. It consists of a single cable that runs to every workstation. This topology uses the least amount of cabling. Each computer shares the same data and address path. With a bus topology, messages pass through the trunk, and
each workstation checks to see if a message is addressed to it. If the address of the message matches the workstation’s address, the network adapter retrieves it. If not, the message is ignored.

Question 21

Star Topology:

Answer 21

A star topology (also called a hub-and-
spoke topology) branches each network device off a central device called a hub or a switch, making it easy to add a new workstation. If a workstation goes down, it does not affect the entire network; if the central device goes down, the entire network goes with it. Because of this, the hub (or switch) is called a single point of failure.

Star topologies are very easy to install. A cable is run from each workstation to the
switch. The switch is placed in a central location. Star topologies are more expensive to install than bus networks because several more cables need to be installed, plus the switches. But the ease of reconfiguration and fault tolerance (one cable failing does not bring down the entire network) far outweigh the drawbacks. This is by far the most commonly installed network topology in use today.

Question 22

Ring Topology:

Answer 22

In a ring topology, each computer connects to two other computers, joining them in a circle and creating a unidirectional path where messages move from workstation to workstation. Each entity participating in the ring reads a message and then regenerates it and hands it to its neighbor on a different network cable.

The ring makes it difficult to add new computers. Unlike a star topology network, a
ring topology network will go down if one entity is removed from the ring. Physical ring
topology systems rarely exist anymore, mainly because the hardware involved was fairly expensive and the fault tolerance was very low.

Question 23

Mesh Topology:

Answer 23

The mesh topology is the most complex in terms of physical design. In this topology, each device is connected to every other device. This topology is rarely found in wired LANs, mainly because of the complexity of the cabling.

Because of its design, the physical mesh topology is expensive to install and maintain.
Cables must be run from each device to every other device. The advantage you gain is high fault tolerance. With a mesh topology, there will always be a way to get the data from source to destination. The data may not be able to take the direct route, but it can take an alternate, indirect route. For this reason, the mesh topology is often used to connect multiple sites across WAN links. It uses devices called routers to search multiple routes through the mesh and determine the best path. However, the mesh topology does become inefficient with five
or more entities because of the number of connections that need to be maintained.

Question 24

Hybrid Topology:

Answer 24

The hybrid topology is simply a mix of the other topologies. Most networks today are not only hybrid but heterogeneous. (They include a mix of components of different types and brands.) The hybrid network may be more expensive than some types of network topologies, but it takes the best features of all the other topologies and exploits them.

Question 25

What are Network Interface Cards ?

Answer 25

Also referred to as a network adapter cards, provide the physical interface between computer and cabling, and prepares data, sends data, and controls the flow of data. It can also receive and translate data into bytes for the CPU to understand.

The most important goal of the NIC is to optimize network performance and minimize the amount of time needed to transfer data packets across the network. The key is to get the fastest card that you can for the type of network that you’re on.

NICs can send data using either full-duplex
or half-duplex mode. Half-duplex
communication means that between the sender and receiver, only one of them can
transmit at any one time. In full-duplex
communication, a computer can send and receive data simultaneously. The main advantage of full-duplex over half-duplex
communication is performance. NICs (Gigabit Ethernet NICs) can operate twice as fast (1 Gbps) in full-duplex mode as they do normally in half-duplex mode (500 Mbps). In addition, collisions are avoided, which speeds up performance as well.

Question 26

What is MAC address ?

Answer 26

A unique hardware address, called a Media Access Control address or MAC address. If two NICs on the same network have the same hardware address, neither one will be able to communicate. For this reason, the IEEE has established a standard for hardware addresses and assigns blocks of these addresses to NIC manufacturers, who then hardwire the addresses into the cards. MAC addresses are 48 bits long and written in hexadecimal

Question 27

Three main types of physical cabling:

Answer 27

Coaxial
Twisted pair
Fiber-optic

Question 28

Fiber-Optic Cable:

Answer 28

Fiber-optic cabling consists of a thin, flexible glass or plastic fiber surrounded by a rubberized outer coating. It provides transmission speeds from 100 Mbps to 10 Gbps over a maximum distance of several miles. Because it uses pulses of light instead of electric voltages to transmit data, it is
immune to electrical interference and to wiretapping.

Question 29

Coaxial Cable:

Answer 29

Coaxial cable (or coax) contains a center conductor core made of copper, which is surrounded by a plastic jacket with a braided shield over it. Either Teflon or a plastic coating covers this metal shield.

Question 30

Twisted Pair Cable:

Answer 30

Twisted pair is the most popular type of cabling to use because of its flexibility and low cost. It consists of several pairs of wire twisted around each other within an insulated jacket.

Question 31

Cable/Digital Subscriber Line (DSL) Modems:

Answer 31

Cable modems use television cable lines, and DSL modems use telephone lines. Both cable and DSL modems are digital and therefore aren’t technically modems because they don’t modulate and demodulate analog signals.

Question 32

Optical Network Terminal (ONT) Modem:

Answer 32

An optical network terminal (ONT) modem is a modem that uses a fiber-optic cable for connectivity. it takes optical signals and changes them into electrical ones for your network.

Question 33

What are Repeaters and Extenders ?

Answer 33

A repeater, or extender, is a small, powered device that receives a signal, amplifies it, and
sends it on its way. The whole purpose of a repeater is to extend the functional distance of a cable run.

Question 34

What is a Hub ?

Answer 34

A hub is a device used to link several computers together. Hubs are very simple devices that possess no real intelligence. They simply repeat any signal that comes in on one port and copy it to the other ports (a process that is also called broadcasting).

There are two types of hubs: active and passive.

Passive hubs connect all ports together
electrically but do not have their own power source.
Active hubs use electronics to amplify and clean up the signal before it is broadcast to the other ports. Active hubs can therefore be used to extend the length of a network, whereas passive hubs cannot.

Patch Panels
A patch panel is essentially a large hub that is rack mounted. It houses multiple cable connections but possesses no network intelligence. Its sole purpose is to connect cables together.

Question 35

What are Routers ?

Answer 35

Routers are highly intelligent devices that connect multiple network types and determine the best path for sending data. They can route packets across multiple networks and use routing tables to store network addresses to determine the best destination. Routers operate at
the Network layer (Layer 3) of the OSI model. Because of this, they make their decisions on
what to do with traffic based on logical addresses, such as an IP address.

Routers have a few key functions:
They connect multiple networks to each other
Routers do not forward broadcasts.
Routers are normally used to connect one LAN to another.

Question 36

What is a Firewall ?

Answer 36

A firewall is a hardware or software solution that serves as your network’s security guard.
They’re probably the most important devices on networks that are connected to the Internet. Firewalls can protect you in two ways:
they protect your network resources from hackers
they can simultaneously prevent computers
on your network from accessing undesirable content on the Internet.

Question 37

What is CSMA/CD ?

Answer 37

Carrier Sense Multiple Access with Collision Detection (CSMA/CD) specifies that the NIC
pause before transmitting a packet to ensure that the line is not being used. If no activity is
detected, then it transmits the packet. If activity is detected, it waits until it is clear. In the case of two NICs transmitting at the same time (a collision), both NICs pause to detect and then retransmit the data. CSMA/CA listens to the line as well but tries to avoid collisions.

Question 38

What is Plenum ?

Answer 38

For areas where a cable must be fire retardant you must run plenum-grade cable. Plenum refers to the coating on the sleeve of the cable, not the copper or fiber within the cable itself.

Question 39

What is the standard that broadcasts and receives signals on 2.4GHz and 5GHz frequencies?

Answer 39

The IEEE defined the 802.11 standard for wireless communication with the 2.4GHz and 5GHz frequency bands.

Question 40

What is the maximum distance for Bluetooth communications?

Answer 40

10 meters

Question 41

What does SSID stand for ?

Answer 41

Service Set Identifier (SSID) is a unique name selected to define and identify a wireless network.

Question 42

What is Quality of Service (QoS) ?

Answer 42

QoS allows for networks to be able to prioritize traffic, most commonly sensitive voice traffic like VoIP.