VPN Bandwidth

Hello,

This may be a stupid question so please bear with me. I have just recently started using a VPN and have noticed an increase in bandwidth usage. Is this normal (or am I just imagining it)? If this is normal, is it due to the encryption and/or the increase in UDP traffic since I use UDP to connect? Thanks for bearing with a newbie to VPN services...

 

My understanding is that VPN encryption bandwidth overhead is somewhere in the neighborhood of just under 10 percent (increase in bandwidth). Reason is that each of your normal packets must be put into an encrypted packet; and each new encrypted packet has its own header that tells the VPN service where the encrypted packet should be sent. My 10 percent number may be just a little high, but there definitely is bandwidth overhead (increase) due to VPN.

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Hello,

Thanks for the confirmation... I am glad that I was not being overly paranoid and imagining things ...

 

I may be wrong or not thinking correctly, but I thought it would be lower because of compression used while a VPN is working.

 

Hello,

I did a lot of web searching and the answers I found tended to be inconsistent. Some sites said the bandwidth difference was not noticeable while others claimed the bandwidth was slightly lower. The majority of the sites I visited claimed an increase of anywhere from 8 to 12 per cent. I did notice a lot of technical jargon mentioned on the sites about the different setups of the VPN and how it affected bandwidth. Nothing in a language I could understand as I was looking for bandwidth usage for the type of VPN the average home user would implement (AirVPN, iVPN, Mulvad, Boleh, etc.). I did some very basic testing here on my system and I did see about a 10 per cent increase in bandwidth with VPN over a standard internet connection. I just downloaded a few large files both ways and compared the results.

This seems to be the most common explanation that I found for the increase.

 

VPN tunnels , especially UDP-based ones, ping constantly to verify connectivity. But that should be minor compared to actual use. If you leave the VPN connected 24/7 and don't download a lot, such overhead might add up.

If you're using TCP-based connections, and have poor ISP connectivity, you may see lots of TCP retransmission. Running TCP (your download) over TCP (your VPN) can lead to overlapping retransmission for each TCP connection. That overhead could be quite substantial for large downloads.