Topologies overview

Question 1

is a single line of devices connected together by one shared network cable. are typically drawn as a single straight line, the network cable is rarely as straight. Often the cable is passed around walls or cubicles so that each computer can be attached to the network. computers connect to the network by physically tapping into the network cable using special adapters. This allows the network cable to remain one continuous conduit while also allowing the computers to send and receive electrical signals on the cable.

Answer 1

bus network topology
The network in a bus topology is also referred to as a network segment because the network may be extended by adding more segments of cable to either end of the network, allowing more computers to connect to the shared network. This may seem like a good idea but can have significant negative consequences.

Question 2

communicate in half-duplex mode, meaning that you can either send or receive at any given time but cannot send and receive simultaneously. Also, the network cable is a shared communications medium, meaning that all computers attached to the network will receive any and all traffic sent on the network. You can visualize a one-lane road over a bridge, where cars must take turns traveling back and forth. This type of network performs well for a small number of computers but as it becomes more populated, it becomes exponentially more difficult to communicate with each other due to the collisions that occur when two or more computers attempt to transmit at the same time.

Answer 2

computers on bus networks
Although a bus topology is very simple and usually inexpensive, overcrowding of devices can make the network unstable or unusable. And if the network cable is broken or cut, the entire network becomes unusable.

Question 3

was created to combat one of the more challenging aspects of the bus network: traffic collisions

Answer 3

The ring topology
changes the way that computers know when to transmit and receive. do not have to be physically arranged in a circle or even a ringlike shape

Question 4

the network cable is interrupted by each computer on the ring, and the cable is connected back to itself instead of using terminators. In a ring topology, the cable enters a “ring in” port on the network card of the computer and exits a “ring out” port on its way to the next computer in the ring. By definition, a ring is a closed-loop, and the ring topology is no exception. When building a ring topology, even if the computers are all physically arranged in a straight line, the network cable will always connect to itself. The cable exiting the “ring out” port on the last computer will be fed into the “ring in” port on the first computer, thereby closing the loop.

Answer 4

ring topologies

Question 5

there are two sets of cables, and each computer has two network cards, one for each ring. In the event of a single cable break, the second ring can take over, allowing network traffic to continue to flow. However, its greatest benefit in the event that both rings are simultaneously cut. In this case, the two loose ends on either side of the cable break can be connected together, merging the two broken rings into one much larger, but continuous, ring, where traffic can flow. is commonly found in fiberoptic networks, such as the synchronous optical network (SONET) ring.

Answer 5

dual-ring topology

Question 6

also known as a hub-and-spoke network, is an improvement upon the bus topology previously described. is composed of a central network device, such as an Ethernet switch, connected to various network devices, such as servers, computers, and printers, by individual network cables

Answer 6

Star Topolgy
The name of the topology is derived from its shape in a network diagram. When drawn, the various lines connecting the switch to the network devices appear like the spokes of a wheel or the rays of light emanating from a star in the center.

Question 7

each device is only connected to the central switch. All device-to-device communication is sent through the switch at the center of the network and then forwarded by the switch to the proper destination. are the most common type of network found in local area network (LAN) & WAN environments

Answer 7

star networks
One key advantage of this topology is versatility. Instead of running cables from computer to computer, in a star topology, network cables are often run in the walls to a central closet

Question 8

are often drawn as a web of direct connections between computers or nodes in a network

Answer 8

mesh topology permits nodes to communicate with each other; the topology may be either a full mesh, where every node has access to all other nodes, or a partial mesh network, where each node is only able to connect to a subset of the other nodes.

Question 9

The nodes may connect using Wi-Fi or radio signals or by virtual links such as virtual private networks (VPNs)

Answer 9

mesh togologies
are typically used where communication within a network must be highly available and redundancy is needed

Question 10

The nodes within a ___ network can communicate with each other, and these connections can be changed dynamically if one node were to fail. This behavior is often referred to as a self-healing network because the nodes in the mesh are aware of each other and can establish new connections around failed nodes as needed

Answer 10

mesh
Common use cases include wireless networks at home and in the office, as well as large collections of routers, such as on the internet.

Question 11

Organizations use a mixture of network architectures that may include centralized,
decentralized, client/server, peer-to-peer, or wired/wireless options depending on the
application and use case.

Answer 11

Network Architectures

Question 12

networks where computing and network power is ____ in a
large, secure data center where users log on to dumb terminals to access mainframe data and
perform tasks.

Answer 12

Centralized

Question 13

networks that rely on the computing power in the user’s device and
enable users to operate without a network connection and be portable. Some challenges of
include storage, local security, and differences in operating systems and

Answer 13

Decentralized

Question 14

networks offload some of the computing requirements from the data center’s
servers, allowing application designers to implement advanced user interfaces in a web-based
or terminal-based application. However, application designers are not the only ones benefitting
from client/server architecture.

Answer 14

Client/Server

Question 15

network, client computers act as both servers and workstations because they
share files and printers while allowing use of the client computer for normal tasks.

Answer 15

Peer-to-Peer

Question 16

networks are
great for portability. The challenge is the strength and stability of that wireless signal

Answer 16

Wireless

Question 17

networks are difficult to make portable but have very stable connections. However, some
wireless technology is faster than wired.

Answer 17

Wired

Question 18

what is the CIA triad

Answer 18

confidentiality, integrity, and availability

Question 19

is a reference model to help protect information from unauthorized disclosure and modification while ensuring it is accessible and intelligible to its authorized users

Answer 19

CIA

Question 20

Confidentiality

Answer 20

limits access
to prevent an unauthorized user from accessing, copying, or transmitting the information.

Question 21

integrity

Answer 21

enables you to trust the information
to identify where the information came from and if the data has changed since it was originally sent

Question 22

availability

Answer 22

ensures that you have access to the information
adding high availability to your server solutions and minimizing downtime by carefully managing your application updates and patches.

Question 23

what ways to breach or compromise the confidentiality of data

Answer 23

Unencrypted information is easy to steal and change.
Deleted files are rarely purged from a disk immediately and often can be recovered with ease.
The physical theft of a device gives an attacker an unlimited time window to break the encryption of your data.
Social engineering is a method used by attackers to gain an unsuspecting victim’s trust to provide information, such as passwords or server names, or even just to gain physical building access.
Accidents and malfunctions also play into the equation. For example, confidentiality of information can easily be breached by storing files in the wrong location, emailing data to the wrong person, or printing confidential information to a public printer.

Question 24

help prevent compromises: confidentiality

Answer 24

Where possible, encrypt the information at-rest (where it is stored) and in-transit (while it is moving across the network).
Be sure to encrypt and physically secure your laptops, servers, portable hard drives, and even backup tapes/disks.
Consider using a tool to securely delete files or overwrite them after deletion.
Train your employees about social engineering attacks.
Create and enforce a policy that ensures all users must use complex passwords (a combination of uppercase and lowercase letters, numbers, and symbols with a minimum length) and use multifactor authentication (MFA), such as biometrics or a digital key fob.
Following the principle of least privilege (which means you only assign users the minimum permissions needed to perform their jobs), institute restrictive access controls on all data and provide access to information on a need-to-know basis only.

Question 25

compromises of data integrity

Answer 25

Man-in-the-middle attacks, where an attacker changes the contents of the message after it was sent, but before it was received
The intentional or unintentional deletion or modification of data
Malfunctions in equipment that cause data corruption
Natural phenomena such as electromagnetic pulse (EMP) attacks, which can destroy or severely corrupt data

Question 25

common actions that can compromise the availability of data

Answer 25

denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks, which prevent legitimate users from accessing the resource by sending an overwhelming amount of data to the target server;
unplanned downtime due to server crashes or failed upgrades; and
accidental changes to access control lists, which removes access for authorized users.

Question 26

help prevent the compromise of data integrity

Answer 26

Require all data transmissions to use encryption or digital signatures to confirm the identity of the sender and to identify if the message has been changed.
In cases where digital signatures will not work, use one-way hash calculations, such as SHA-3 (Secure Hash Algorithm 3), to create a value that can be used to verify the data has not changed.
Use version control within your data storage to help you quickly revert accidental changes or deletions.

Question 27

methods that can be employed to help prevent availability issues

Answer 27

creating and maintaining a full disaster recovery plan that includes a full site failover as well as the method to restore data for individual servers;
implementing server high availability where possible, employing clustering technology where appropriate; and
setting up regular backups of your data and considering storing a backup copy at another physical location to protect against site-level disasters.