DTSC-620 Cloud Foundations - Networking Basics

Comprehensive practice flashcards covering fundamental networking concepts, the OSI model, CIDR notation, Amazon VPC components, network security mechanisms, and hybrid connectivity solutions based on DTSC-620 Cloud Foundations.

Computer Network

A configuration of two or more client machines connected together to share resources, which can be logically partitioned into subnets and requires a switch or router to enable communication.

Subnet

A logical partition of a computer network that represents a defined range of IP addresses within a Virtual Private Cloud (VPC) and is confined to a single Availability Zone.

Port

A communication endpoint used by software to uniquely identify specific processes or services running on a computer within a network.

Port $80$ (HTTP)

The standard network communication port used for unencrypted web browsing traffic.

Port $443$ (HTTPS)

The standard network communication port used for secure, encrypted web browsing traffic.

Port $22$ (SSH)

The standard network communication port used for secure shell administrative access.

Port $25$ (SMTP)

The standard network communication port used for sending email messages.

Port $53$ (DNS)

The standard network communication port used for domain name resolution to IP addresses.

Physical Layer (OSI Layer 1)

The OSI model layer responsible for the transmission and reception of the medium via electrical, optical, or radio signals ($1\text{s}$ and $0\text{s}$).

Data Link Layer (OSI Layer 2)

The OSI model layer that transfers data across the same local area network (LAN) using MAC addresses, hubs, and switches.

Network Layer (OSI Layer 3)

The OSI model layer responsible for routing and packet forwarding across networks using IP addresses and routers.

Transport Layer (OSI Layer 4)

The OSI model layer that provides protocols such as TCP and UDP to support reliable or datagram host-to-host communication.

Session Layer (OSI Layer 5)

The OSI model layer that enables the orderly exchange and management of data sessions between applications using protocols such as NetBIOS and RPC.

Presentation Layer (OSI Layer 6)

The OSI model layer that handles data representation, encryption, and translation (such as ASCII and ICA) to ensure the application layer can read the data.

Application Layer (OSI Layer 7)

The top OSI model layer providing user application processes with access to network services, utilizing protocols such as HTTP(S), FTP, DHCP, and LDAP.

IPv4 Address

A $32\text{-bit}$ numerical network address represented in dotted-decimal format across four octets ranging from $0$ to $255$.

IPv6 Address

A $128\text{-bit}$ network address represented in eight hexadecimal groups ranging from $0$ to $\text{FFFF}$, providing $2^{128}$ possible addresses.

CIDR (Classless Inter-Domain Routing)

An IP addressing scheme specifying an IP address and prefix length (such as $192.0.2.0/24$) to indicate how many leading bits are fixed network routing prefix bits versus flexible host identifier bits.

AWS VPC CIDR Block Limits

The allowed range of IPv4 CIDR block sizes configurable for an AWS VPC, spanning from a maximum of $/16$ ($65{,}536$ total addresses) to a minimum of $/28$ ($16$ total addresses).

AWS Reserved Subnet IP Addresses

The five IP addresses unavailable for assignment in every AWS subnet CIDR block: the first four addresses (.0 Network Address, .1 VPC Router, .2 DNS Resolution, .3 Reserved for future use) and the last address (.255 Network Broadcast).

Amazon Virtual Private Cloud (Amazon VPC)

A networking service that enables provisioning a logically isolated section of the AWS Cloud dedicated to an account within a single Region, which can span multiple Availability Zones.

Elastic Network Interface (ENI)

A virtual network interface that can be attached to instances in a VPC to provide advanced networking features such as granular traffic monitoring.

Route Table

A set of rules (routes) containing destinations and targets configured to direct network traffic originating from an associated subnet.

Internet Gateway (IGW)

A scalable, redundant, and highly available VPC component that serves as a target in VPC route tables for internet traffic and performs NAT for instances assigned public IPv4 addresses.

Network Address Translation (NAT) Gateway

A managed VPC component residing in a public subnet that enables instances in private subnets to reach the internet or other AWS services while blocking the internet from initiating inbound connections.

VPC Peering

A direct networking connection between two VPCs (across the same or different accounts and Regions) with non-overlapping IP address spaces that routes traffic using private IP addresses.

Transitive Peering

A network design where traffic routes through an intermediary VPC to reach a destination VPC; this behavior is not supported by AWS VPC Peering.

AWS Transit Gateway

A regional network transit hub used to interconnect hundreds or thousands of VPCs and on-premises networks through a central point, eliminating complex point-to-point VPC peering meshes.

AWS Site-to-Site VPN

A fully managed service that creates a secure, encrypted connection between an on-premises data center and AWS resources operating at the network layer.

AWS Direct Connect

A dedicated, private physical network connection linking an on-premises data center or co-location facility directly to AWS without traversing the public internet, offering speeds up to $100\text{ Gbps}$.

AWS Outposts

A family of fully managed solutions delivering physical AWS infrastructure and services directly onto on-premises customer locations in standardized $42\text{U}$ racks for a consistent hybrid cloud experience.

Security Group

A stateful virtual firewall that operates at the instance level, supporting allow rules only (default deny all inbound, default allow all outbound), and automatically permits return traffic.

Network Access Control List (Network ACL)

A stateless virtual firewall that operates at the subnet level, supporting numbered allow and deny rules (default allow all inbound and outbound IPv4), and requiring return traffic to be explicitly allowed.

Amazon Route 53

A scalable, highly available Domain Name System (DNS) web service running on port $53$ that routes end users to internet applications by translating human-readable domain names into IP addresses.

Route 53 Routing Policies

A set of policies governing how Amazon Route 53 responds to DNS queries, including Simple, Weighted round robin, Latency, Geolocation, Geoproximity, Failover, and Multivalue answer routing.

Content Delivery Network (CDN)

A globally distributed system of caching servers that caches static content closer to end users at edge locations or Points of Presence (POPs) to reduce latency and bandwidth consumption.

Amazon CloudFront

A fast, global, and secure Layer 7 Content Delivery Network (CDN) service that caches data, videos, applications, and APIs across a global network of Edge Locations and Regional Edge Caches.

AWS Global Accelerator

A networking service operating at OSI Layers 3 and 4 that optimizes routing paths and reduces latency by directing user traffic through the nearest AWS edge location via an optimal-routing algorithm.