To enable **Tier_1 Networking** (also known as High Bandwidth Networking), you need to meet three specific requirements: use a compatible **machine type**, use the **gVNIC** driver, and enable the **Tier_1 performance configuration** in your Terraform code.
### 1. Requirements Checklist
* **Machine Series:** Must be N2, N2D, C2, C2D, C3, C3D, C4, or M3.
* **vCPU Count:** Most families require a minimum vCPU count to support Tier_1. For example, C3 requires at least **44 vCPUs** to enable Tier_1.
* **Driver:** You **must** use the Google Virtual NIC (gVNIC) driver.
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### 2. Terraform Implementation
In your `google_compute_instance` resource, you need to add the `network_performance_config` block and set the `nic_type` to `GVNIC` within the `network_interface`.
```bash
resource "google_compute_instance" "high_perf_vm" {
name = "rpc-node-tier1"
# Tier_1 requires specific machine types (e.g., c3-standard-44)
machine_type = "c3-standard-44"
zone = "asia-northeast1-b"
boot_disk {
initialize_params {
# Ensure the OS image supports gVNIC
image = "projects/debian-cloud/global/images/family/debian-12"
}
}
network_interface {
network = "default"
# 1. Enable gVNIC driver
nic_type = "GVNIC"
access_config {
# Tier_1 increases Internet Egress from 7 Gbps to 25 Gbps
network_tier = "PREMIUM"
}
}
# 2. Enable Tier_1 Networking Performance
network_performance_config {
total_egress_bandwidth_tier = "TIER_1"
}
}
```
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### 3. Why Enable It?
The primary benefit of Tier_1 Networking is the massive jump in throughput:
| Network Config | Standard Egress | Tier_1 Egress |
| --- | --- | --- |
| **Internal (VPC)** | Up to 10-100 Gbps | **Up to 200 Gbps** |
| **External (Internet)** | Capped at 7 Gbps | **Capped at 25 Gbps** |
### 4. Important Limitations
1. **Cost:** There is an additional per-vCPU hourly charge for enabling Tier_1 performance.
2. **OS Support:** Your Guest OS must have the gVNIC driver installed (all modern Google-provided images have this by default).
3. **Zones:** Tier_1 is only available in zones that support the required 3rd and 4th generation machine families.
