Slow internet speed with Site-to-Site VPN

[todarsey]

I have 2 RV042 routers, one is version 1 and the other is Version 3 and both have up to date firmware loaded. Both ISPs are cable, one is Comcast and the other is Mediacom. I have set both MTUs to various different settings and set the upload download speeds in Bandwidth Management. Speedtest.net shows speeds at office # 1 of 30/5 and office # 2 is 10/2. The VPN connection is always active. My problem seems to be this, if data is ever being transferred between the offices the internet speed for office #2 slows down to 1.5/.12 but there isn't really any notable differences at office #1. Does anyone have any idea of what could cause the drop in speed.

[SamirD]

This makes perfect sense depending on the size of the file. Bandwidth is limited to the speeds you stated, no matter what resource is using them--internet or vpn. Also, a large factor is that with asymmetrical bandwidth that when a lot of upload bandwidth is used, the download bandwidth suffers as well. I bet most of the time when this happens, the file is being transferred from office #2, thereby using up all the available upload bandwidth. Office #1 won't see the effects from file transfer because the file transfer is using download bandwidth not upload bandwidth.