MTU Size
MTU Size determines the largest packet that can be transmitted over a network link. Choosing the right MTU helps avoid fragmentation and ensures optimal performance for your Virtual Network (VNET).
The Wanscale Platform allows you to configure the MTU for WAN interfaces and automatically adjusts overlay MTU values to account for encryption and encapsulation overhead.
When to use MTU Size
- Optimize performance: Use a larger MTU for high-throughput links such as fiber.
- Avoid fragmentation: Match the MTU to your provider or physical link limits.
Underlay and overlay MTU
When you set the MTU for a WAN interface, it applies to the underlay network (the physical connection between your VNET and remote locations). The overlay network then adjusts its MTU based on the underlay value and the additional overhead introduced by encryption and encapsulation.
Tip
Wanscale uses 150 bytes for encryption and encapsulation headers. As a result, the effective overlay MTU is about 150 bytes smaller than the underlay MTU.
| Description | Underlay MTU | Overlay MTU |
|---|---|---|
| Default | 1500 bytes | 1350 bytes |
| Maximum | 9100 bytes | 8950 bytes |
Provider MTU sizes
Provider links may support different MTU values. Consult your provider documentation and use the smallest MTU along the path to avoid fragmentation.
| Provider | Typical MTU |
|---|---|
| Eurofiber | 9000 bytes |
| Odido fiber | 2000 bytes |
| KPN fiber | 1500 bytes |
| Ziggo/Vodafone fiber | 1500 bytes |
| Starlink | 1500 bytes |
| 4G/5G | 1500 bytes |
Configuring MTU Size
- Navigate to your Service Edge device in the Wanscale portal.
- In the left sidebar, expand Interfaces and select WAN.
- Click the Actions menu for the desired port and choose Edit WAN interface.
- Set the MTU Size in the configuration pane.
- Click Save.
Note
Applying Changes: Your new MTU Size will not be active until you deploy the changes. See Workflows and Applying Changes.