# BSI C5 PS-02 — Redundancy model

- Source: https://support.icompaas.com/support/solutions/articles/a_gen_bsic5_ps02_fb54be7c04-bsi-c5-ps-02-redundancy-model
- Section: [Solutions](https://support.icompaas.com/support/solutions) › [BSI C5 (German Cloud)](https://support.icompaas.com/support/solutions/c_gen_bsi_c5) › [Physical Security](https://support.icompaas.com/support/solutions/folders/f_gen_cgenbsic5_physicalsecurity)
- Last updated: 2026-05-30
- Publisher: iCompaas, Inc. (https://www.icompaas.com)

BSI C5 · Control PS-02 · Priority: high · Component: Physical Security

### What this control covers

Provides cloud services from redundant locations meeting PS-01 requirements, ensuring operational continuity per service level agreements. Tests redundancy annually to verify availability, protecting cloud customer data and services from site-specific disruptions.

### Why it matters

A well-architected cloud landing zone bakes most of these controls in at the platform layer — done well, individual workloads inherit security for free.

### How to implement

#### AWS

Segment workloads into separate **VPCs/accounts per environment**. Use **security groups** as stateful allow-lists (least-port, source by SG ID not 0.0.0.0/0) and **VPC Flow Logs** to CloudWatch/S3. Front public services with **AWS WAF + Shield Advanced** and use **PrivateLink/VPC Endpoints** to keep service traffic off the internet.

#### Azure

Use **Network Security Groups** and **Application Security Groups** for east-west, and an **Azure Firewall** or NVA in a hub VNet for north-south. Enforce **Private Endpoints** for PaaS and turn on **Defender for Cloud — Network** for adaptive hardening recommendations.

#### GCP

Use **VPC Service Controls** to draw a perimeter around sensitive APIs and a hierarchical **Firewall policy** at the org/folder level so projects inherit a deny-by-default posture. Front HTTP workloads with the global **Cloud Load Balancer + Cloud Armor**.

### Evidence to collect

-   `infra_scan` — See the iCompaas Evidence library for the canonical source for this evidence type.

Infrastructure posture tooling (AWS Config, Azure Policy, Nessus) verifies platform hardening. Focus: Redundancy model.

### Quick checklist

-   Security — Agreements / Model
-   Physical — Agreements / Model
-   Redundancy — Agreements / Model
-   Data — Agreements / Model
-   Business — Agreements / Model
-   Locations — Agreements / Model

### Related articles on this site

-   [Microsoft Cloud Security Posture Management (CSPM)](https://support.icompaas.com/support/solutions/articles/62000234105-microsoft-cloud-security-posture-management-cspm-)
-   [2.10 Ensure that Microsoft Cloud App Security (MCAS) integration with Security Center is selected](https://support.icompaas.com/support/solutions/articles/62000219760-2-10-ensure-that-microsoft-cloud-app-security-mcas-integration-with-security-center-is-selected)
-   [Ensure that Activity Log Alert exists for Create or Update Network Security Group](https://support.icompaas.com/support/solutions/articles/62000219859-ensure-that-activity-log-alert-exists-for-create-or-update-network-security-group)
-   [5.2.4 Ensure that Activity Log Alert exists for Delete Network Security Group](https://support.icompaas.com/support/solutions/articles/62000219861-5-2-4-ensure-that-activity-log-alert-exists-for-delete-network-security-group)

## Related compliance guidance

- [SOC 2 compliance: a practical implementation guide for cloud-native SaaS teams](https://support.icompaas.com/compliance/soc-2-trust-services-criteria): Configuration checks like this one are the technical half of a SOC 2 / ISO 27001 programme — the guide shows where they fit, what else an auditor expects, and how to evidence them.
- [ISO/IEC 27001:2022 compliance: a practical implementation guide](https://support.icompaas.com/compliance/iso-27001-2022): ISO 27001 Annex A.8 (technological controls) is where cloud hardening evidence lands; the guide shows how to run the ISMS around it.