INFO 2004 Chap.8 VPC Networking, Subnets and Route Tables
VPC Networking, Subnets and Route Tables
A Virtual Private Cloud is presented as a configurable pool of resources with isolation inside a public cloud environment and, for AWS, as a virtual network dedicated to an account. The captured networking spine contains six defined terms: VPC, subnet, route table, internet gateway, VPC endpoint and CIDR block.
Subnets and route tables receive no further teaching prose, so the guide builds only a conceptual decision path and does not introduce CIDR arithmetic, reserved-address counts or sizing rules.
The deeper sourced asset is the contrast between security groups and network ACLs: instance versus subnet level, allow-only versus allow-and-deny rules, stateful versus stateless behaviour, all-rule versus ordered evaluation, and explicit association versus automatic subnet application.
Content delivery adds CDN purpose, CloudFront and Route 53, but this half is also thin and avoids service-specific mechanics not stated in the course materials.
What this chapter covers
- 01
VPC as an isolated virtual network
- 02
The six-term concept spine
- 03
Subnet as an address range inside a VPC
- 04
Route table as rules directing traffic
- 05
Internet gateway and VPC endpoint concepts
- 06
Security groups compared with network ACLs
- 07
CDN purpose, CloudFront and Route 53
Diagnose two VPC control failures
- 1Scope: inspect the security group for an instance-level issue and the network ACL for a subnet-level issue.
- 1Rule type: a deny rule can exist in the network ACL, while the security group supports allow rules only.
- 1State: return traffic is automatic for the stateful security group but must be allowed for the stateless network ACL.
- 1Evaluation: consider all security-group rules, but read network-ACL rules in order from the lowest number.
- 1Association: check explicit instance association for the security group and subnet association for automatic ACL application.
Key terms
- VPC
- A virtual network dedicated to an AWS account and used to place resources inside a defined network boundary.
- Subnet
- The range of IP addresses in a VPC.
- Route table
- A set of routes used to determine where network traffic is directed.
- Internet gateway
- A gateway attached by the customer to enable communication between VPC resources and the internet.
- VPC endpoint
- A private connection from a VPC to supported services without requiring the public path described in the source definition.
- CIDR block
- An internet protocol address-allocation and route-aggregation methodology.
- Security group
- An instance-level, allow-only, stateful virtual firewall control.
- Network ACL
- A subnet-level, allow-and-deny, stateless firewall layer processed in ordered rules.
VPC Networking, Subnets and Route Tables FAQ
What six VPC concepts are defined?
VPC, subnet, route table, internet gateway, VPC endpoint and CIDR block.
What is the scope difference between the two firewall controls?
Security groups operate at instance level; network ACLs operate at subnet level.
Which control is stateful?
The security group is stateful. The network ACL is stateless.
How much subnetting depth is captured here?
Only the six-term concept list. Confirm the missing networking-basics and practical materials on Canvas.
What is the CDN source caveat?
A page heading says subnetting, but its body describes a CDN video. This guide treats it as CDN material and not subnet evidence.
Assessment move
Memorise the six VPC terms as one flow: boundary, address range, direction rules, public gateway, private endpoint and addressing method. Then drill all five security-group and network-ACL contrasts in paired sentences. Keep a deliberate boundary around subnetting detail and CDN mechanics, since the missing pages and brief definitions do not ground the usual technical expansions.
Working through VPC Networking, Subnets and Route Tables in INFO 2004? Sia is AskSia’s AI Computer Science tutor — ask any INFO 2004 VPC Networking, Subnets and Route Tables question and get a clear, step-by-step explanation grounded in how INFO 2004 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.
