4.1.1. Load Balancer SKUs and Types
SKUs:
| Feature | Basic | Standard |
|---|---|---|
| Backend pool size | 300 instances | 1,000 instances |
| Health probes | TCP, HTTP | TCP, HTTP, HTTPS |
| Availability zones | No | Zone-redundant |
| SLA | No | 99.99% |
| Security | Open by default | Closed by default (requires NSG) |
| Outbound rules | No | Yes |
| Global tier | No | Yes (cross-region) |
💡 First Principle: Standard is the only SKU available for new deployments — Basic Load Balancer was retired on 30 September 2025 and can no longer be created. Existing instances keep running without support or an SLA. As with public IPs, the exam tests the migration: moving to Standard means outbound access becomes explicit rather than implicit, and the SKU of the attached public IP has to move in the same step.
Types:
| Type | Frontend IP | Use Case |
|---|---|---|
| Public | Public IP | Internet-facing applications |
| Internal | Private IP | Internal applications, multi-tier |
| Gateway | Transparent | Inline NVA insertion |
Regional vs Cross-Region:
| Scope | Regional | Cross-Region (Global) |
|---|---|---|
| Latency | Lowest | Adds hop |
| Failover | Within region | Between regions |
| Use case | Most workloads | DR, global presence |
The cross-region (Global) tier puts a single static anycast frontend IP in front of regional Standard load balancers, which become its backend pool. Clients keep one address no matter which region serves them, and traffic is steered to the closest healthy region. Two properties get tested: the global frontend IP does not change during a regional failover, and the backend pool members are load balancers rather than VMs.
⚠️ Exam Trap: Cross-region Load Balancer and Traffic Manager both give a multi-region answer but at different layers. Cross-region Load Balancer keeps a single IP address and stays in the data path at Layer 4. Traffic Manager works at DNS, hands back a different address per region, and then leaves the path entirely.
