SMB quasions

[nichky]

Hi There,

have a 1 Gbps WAN link and I’m sharing files over a VPN connection.
The measured latency is around 16 ms.

However, the maximum file transfer speed I’m seeing is about 200 Mbps, even though the VPN tunnel itself can reach up to 900 Mbps.

Is there a formula or method to calculate expected file-sharing speed based on latency? I’d like to understand whether this behavior is expected or if there are tuning options I should look into.

 

[ColinTaylor]

Is your WAN link 1 Gbps in both directions, upload and download?
Is that the same for both sides of the VPN tunnel?

Are you saying that only SMB file transfers are running at 200 Mbps over the tunnel, or that all traffic runs at 200 Mbps over the tunnel?

What hardware is the VPN server and VPN client running on?

 

[nichky]

The CPE is provisioned at 1G / 400 Mbps.
The core device is 10G.

Download speeds from the CPE are limited to around 200 Mbps, while upload reaches the expected higher speeds.
I tested multiple tunnel types, including L2TP, WireGuard, SSTP, OpenVPN, and PPTP, but the behavior remains the same.

CPU usage on both the CPE and core devices is normal, averaging around 10%.

I have a similar setup at another site where the remote end is on fiber (essentially LAN-to-LAN), and it consistently reaches 1 Gbps.

I’ve read that latency can significantly impact throughput, which may explain the difference.