Network Fundamentals

Question 1

Clients

Answer 1

Devices that users use to access the network (e.g., workstations, laptops,
tablets)

Question 2

Servers

Answer 2

Provide resources to the network (e.g., email servers, file servers)

Question 3

Hubs

Answer 3

Older technology connecting devices but not commonly used due to
limitations

Question 4

Switches

Answer 4

Smarter hubs that ensure security and efficient bandwidth utilization

Question 5

Wireless Access Points (WAPs)

Answer 5

Enable wireless devices to connect to a wired network using radio
frequency waves

Question 6

Routers

Answer 6

Connect different networks, make intelligent forwarding decisions based
on IP addresses

Question 7

Firewalls

Answer 7

Security barrier between internal network and the internet, monitor and
control traffic

Question 8

Load Balancers

Answer 8

Distribute network/application traffic across servers, preventing
bottlenecks

Question 9

Proxy Servers

Answer 9

■ Act as intermediaries between user devices and the internet, enhancing
security and privacy

Question 10

Intrusion Detection Systems (IDS)

Answer 10

■ Detect unauthorized access or anomalies

Question 11

○ Intrusion Prevention Systems (IPS)

Answer 11

■ Detect and take action to prevent intrusion

Question 12

○ Controllers

Answer 12

■ Manage flow control in software-defined networking (SDN), offering
flexibility and efficiency

Question 13

Network-attached Storage (NAS) Devices

Answer 13

■ Dedicated file storage systems providing data access to authorized clients

Question 14

Storage Area Networks (SANs)

Answer 14

High-speed networks for consolidated block-level data storage, enhancing
accessibility

Question 15

Media

Answer 15

■ Physical materials for data transmission (e.g., copper cables, fiber optic cables)

Question 16

Wide Area Network (WAN) Links

Answer 16

Connect networks over large areas (e.g., between cities), essential for
global connectivity

Question 17

Explain the Client/Server model

Answer 17

Utilizes a dedicated server for centralized access to files, scanners,
printers, and resources
■ Easy administration and backup due to a central server

Benefits
● Centralized administration
● Easier management
● Better scalability

Drawbacks
● Higher cost
● Requires dedicated hardware and specialized skillset
■ Leading model in business networks

Question 18

Explain the Peer-to-Peer Model

Answer 18

■ Direct sharing of resources among peers (laptops, desktops)
■ Difficult administration and backup due to dispersed files on different
machines

Drawbacks
● Redundancy
● Complex management
● Scalability issues
■ Useful for low-cost setups, exemplified by Napster a decade ago

Benefits
● Low cost
● No specialized infrastructure or hardware
■ Drawbacks
● Decentralized management
Poor scalability for large networks
■ Not recommended for business networks

Question 19

What is a Personal Area Network (PAN)

Answer 19

Personal Area Network (PAN)
■ Smallest network type
■ Covers about 10 feet or less
■ Examples are Bluetooth and USB
■ Connection within arm’s reach

Question 20

What is a Local Area Network (LAN)

Answer 20

Local Area Network (LAN)
■ Common in office buildings
■ Limited distance
● Up to 100 meters
● CAT 5 cabling
■ Can use WiFi (IEEE 802.11) or Ethernet (IEEE 802.3)
■ Examples include Office, school, and home

Question 21

Wha is a Campus Area Network (CAN)

Answer 21

Campus Area Network (CAN)
■ Building-centric LAN
■ Spans numerous buildings in an area
■ Covers several miles
■ Examples are College campuses, business parks, military bases

Question 22

Metropolitan Area Network (MAN)

Answer 22

■ Connects locations across the entire city
■ Larger than CAN
● Up to 25 miles
■ Examples are City departments, multiple campuses in a city

Question 23

Wide Area Network (WAN)

Answer 23

■ Connects geographically disparate internal networks
■ Large geographic coverage
● Across states, countries, or globally
■ Can consist of lease lines or VPNs.
■ Examples are Internet, private connections between offices across the country.
- They don’t have to be public

Question 24

Physical Topology

Answer 24

● Describes physical cabling and device connections
● Represents real-world layout using floorplans

Question 25

Logical Topology

Answer 25

● Describes how data flows in the network ● Focuses on the logical connection rather than physical placement

Question 26

Ring Topology

Answer 26

● Circular data path with each device connected to two others ● Unidirectional flow prevents collisions ● Creates a single point of failure situation unless there are redundant connections for failover ● Common in FDDI (Fiber Distributed Data Interface) for long-distance fiber optic networks

Question 27

Bus Topology

Answer 27

● All devices connected to a central cable (bus) ● Data accessible to all, but only intended recipient processes it ● Easy to install ● If the main cable fails, the network won’t work ● The more devices connected to the network, the more collisions will occur ● Older technology, not common in modern networks

Question 28

Star Topology

Answer 28

● Each node connected to a central point (network switch). ● Robust, but network depends on the central point's functionality ○ If the central point fails, the entire network fails ● Common in home networks

Question 29

Hub-and-Spoke Topology

Answer 29

● Variation of star topology with a central hub connected to multiple spokes ● Nodes transmit data to the hub before reaching the final destination ● Used in airline and telecommunications networks ● Less expensive for larger networks

Question 30

Mesh Topology

Answer 30

● Point-to-point connections between every device for redundancy ● Provides robustness and redundancy but can be complex and costly

Question 31

Full mesh

Answer 31

every node connected to every other ● Mesh Topology Formula ○ Full mesh connections formula ■ n (n-1)/2 ■ n is the number of nodes

Question 32

Partial mesh

Answer 32

some nodes fully interconnected, others connected to one or two devices. Redundancy is not as good as full mesh.

Question 33

Infrastructure Mode

Answer 33

■ Centralized wireless network with a wireless access point ■ Similar to a star topology in a physical network ■ Common in homes ● Connects to an outside provider through a cable or fiber modem ■ Supports wireless security controls

Question 34

Ad Hoc Mode

Answer 34

■ Decentralized wireless network ■ Operates like a peer-to-peer network ■ No routers or access points ● Devices connect directly ■ Dynamic routing decisions made on the fly ■ Allows for dynamic joining and leaving of devices ● Resembling old-school chat rooms

Question 35

Wireless Mesh

Answer 35

■ Unique interconnection of different nodes, devices, and radios ■ Creates a mesh topology for expansion and redundancy ■ Combines various technologies for connectivity ● Bluetooth, WiFi, microwave, cellular, satellite ■ Enables large-scale network access in harsh environments ■ Uses different radio frequencies to establish reliable connections ■ Use Cases for Wireless Mesh ● Post-disaster scenarios ● Humanitarian assistance missions ● Combining microwave, satellite, cellular, and WiFi for reliable and redundant networks ○ Satellite for long distances ○ Microwaves for medium ranges ○ Wireless for short distances

Question 36

Datacenter

Answer 36

■ Any facility composed of networked computers and storage that businesses and other organizations use to organize, process, store, and disseminate large amounts of data

Question 37

Three-Tiered Hierarchy

Answer 37

■ Core Layer ● Houses high-performance routers, merging geographically separated networks ● Backbone of the network

Question 38

Distribution/Aggregation Layer

Answer 38

● Provides boundary definition through access lists and filters ● Defines policies for the network at large ● Uses layer 3 switches for routing between subnets ○ Ensure the packets are properly routed between different subnets and VLANs

Question 39

Access/Edge Layer

Answer 39

● Connects endpoint devices using regular switches ● Used to ensure the packets are converted to frames and delivered to the correct end point devices ■ Having 3 layers provides better ● Performance ● Management ● Scalability ● Redundancy ■ It also helps with troubleshooting because the layers and devices provide points at which parts of the network can be isolated to determine problems and maintain the rest of the network while the isolated part is fixed

Question 40

Collapsed Core

Answer 40

● Network architecture where the core and distribution layers are merged into a single layer ● Creates a two tiered core ● Simplified architecture for medium to small datacenters ● May not be suitable for larger and more complex networks

Question 41

Spine and Leaf Architecture

Answer 41

■ An alternative type of network architecture that is used specifically within datacenters ■ Focuses on communication within datacenters, particularly server farms ■ Consists of 2 switching layers

Question 42

Leaf

Answer 42

○ Consists of all the access switches that will aggregate traffic from the different servers and then connect directly into the spine layer

Question 43

Spine

Answer 43

○ Contains switches that interconnect all the leaf layer switches into a full-mesh topology ■ Enhances speed, and reduces latency compared to traditional three-tiered hierarchy ■ Works well with a Software Defined Network (SDN) ■ Can also be used in combination with the standard three-tiered hierarchy ● Servers in the datacenter connect to leaf layers ● Spine connects to the core layer of the three-tiered hierarchy

Question 44

North-South Traffic

Answer 44

● Traffic that enters (Southbound traffic) or leaves (North traffic) data center from a system outside

Question 45

East-West Traffic

Answer 45

● Data flow within a datacenter ● Example: In a spine and leaf architecture, all data flow between servers is considered east-west traffic ● Prevalent with SDN, virtualization, and converged networks