FRITZ!Box 4040 Service - Knowledge Base
VPN connections are slow
When transferring over a VPN connection between a computer and a FRITZ!Box or between two FRITZ!Box networks, the throughput rates are lower than the rates allowed by the respective internet connections.
Throughput lower due to functional principle
The highest possible throughput that can be achieved over a VPN connection is influenced by the
- speed of both internet connections.
- additional overhead resulting from VPN encryption.
- the overhead of the software or communications protocols (SMB, FTP, VoIP) being used.
Depending on the type of files to be transferred and communications protocols being used, the additional overhead resulting from VPN encryption is 4% to 74%. VPN overhead rarely reduces the throughput by over 20%; however, it is possible for this to occur. Normally the upload of the VPN remote site's internet connection limits the throughput the most.
FRITZ!Box A is being used on an internet connection with 50 Mbit/s downstream und 10 Mbit/s upstream; FRITZ!Box B is being used on an internet connection with 6000 kbit/s downstream und 512 kbit/s upstream.
When data is copied from FRITZ!Box A to FRITZ!Box B, download is limited to max. 6 Mbit/s by FRITZ!Box B's downstream. If files are copied from FRITZ!Box B to FRITZ!Box A, download is limited to max. 512 kbit/s by FRITZ!Box B's upstream. The user data rate can be reduced to 1.5 Mbit/s or 133 kbit/s by the VPN overhead.