Infrastructure as a Service (IaaS)
- Foundational cloud service model that provides virtualized computing resources over the internet
- Customer rents IT infrastructure (servers, VMs, storage, networks, operating systems) from cloud provider on pay-as-you-use basis
- Provider manages physical hardware, hypervisors, and data center facilities while customer controls everything above the hypervisor layer
- Most flexible cloud model - gives customers nearly complete control over their computing environment without physical hardware ownership
Key Components
- Compute Resources: Virtual machines with configurable CPU, RAM, and processing power
- Storage: Block storage, object storage, and file systems (typically with redundancy and backup options)
- Networking: Virtual networks, load balancers, firewalls, VPNs, and public IP addresses
- Operating Systems: Customer chooses and manages OS installations and configurations
IaaS vs Other Cloud Models
| Service Model | Provider Manages | Customer Manages | Example Use Case |
|---|---|---|---|
| IaaS | Hardware, hypervisor, physical network | OS, middleware, runtime, applications | Migrating existing applications to cloud |
| PaaS | Hardware through runtime environment | Applications and data | Web application development |
| SaaS | Everything except user data/settings | User access and data | Email, CRM, productivity software |
Network Engineering Relevance
- Hybrid Cloud Connectivity: Requires VPN tunnels or dedicated connections (AWS Direct Connect, Azure ExpressRoute) between on-premises and IaaS environments
- Virtual Network Design: Must understand VPC (Virtual Private Cloud) concepts, subnetting within cloud environments, and security group configurations
- Load Balancing: IaaS providers offer various load balancing options (Layer 4/7) that integrate with traditional network designs
- Bandwidth Considerations: Data transfer costs and latency impact network architecture decisions (especially for hybrid deployments)
Common IaaS Providers and Features
| Provider | Key Networking Features | Typical Use Cases |
|---|---|---|
| AWS EC2 | VPC, Elastic Load Balancing, Route 53 DNS | Enterprise applications, backup/DR |
| Microsoft Azure | Virtual Networks, Traffic Manager, ExpressRoute | Windows-centric environments, hybrid cloud |
| Google Cloud | VPC, Cloud Load Balancing, Cloud DNS | Analytics, machine learning workloads |
| VMware vCloud | NSX integration, enterprise networking | VMware shop migrations |
Vocabulary
- Hypervisor: Software layer that creates and manages virtual machines (Type 1: bare metal, Type 2: hosted)
- Virtual Private Cloud (VPC): Logically isolated section of cloud where you launch resources in a virtual network you define
- Elastic/Auto-scaling: Automatic adjustment of computing resources based on demand patterns
- Multi-tenancy: Multiple customers sharing the same physical infrastructure while maintaining logical separation
- Service Level Agreement (SLA): Contract specifying uptime guarantees (typically 99.9% or higher for enterprise IaaS)
Notes
- Cost Management Critical: IaaS pricing can escalate quickly - monitor resource utilization and implement auto-shutdown policies for non-production environments
- Security Shared Responsibility: Provider secures physical infrastructure, but customer responsible for OS patches, network ACLs, and application security
- Vendor Lock-in Risk: Each provider uses proprietary APIs and services - design with portability in mind if multi-cloud strategy is important
- Network Latency Considerations: Choose regions/availability zones closest to users, and understand that inter-region traffic often incurs additional costs
- Backup Strategy Essential: IaaS doesn’t automatically backup your data - implement proper backup and disaster recovery procedures
- For CCNA context: Understanding IaaS networking helps with modern network designs where traditional on-premises networks extend into cloud environments through VPNs and hybrid connectivity solutions