I am using Zeroshell for a while now and used VPN bonding to aggregate two 4/0,5 Mbit/s DSL lines.
Now i got vectoring and have two 100/40 Mbit/s lines that i like to bond as before. The bonding is working fine, but the performance is quite bad.
I was hoping for about 180/70 Mbit/s , but instead i get 110/25 Mbit/s out of the two lines. The upload is even worse then on a single line. After looking at wireshark, i found out that about 35% of the traffic are ack.flags that report about out of order packets, Dup Ack and retransmitting.
If i only use one line over the VPN (failover mode) i get around 90/32 Mbit/s with under 7% ack.flags.
I also tested some mtu settings, but they don’t helped at all.
I hope someone knews that issue and has a solution to fix it.
Some information about my setup:
One Server in a Datacenter with a 250/250 line with two IPs that is running zeroshell.
At home i have two fritzbox routers (only using them as a modem) that are passing the connection to my zeroshell box.
The VPN is using AES-256-CBC encryption, but it doesent make any difference for the connection speed. Both Zeroshell boxes are not anywhere near 100% CPU load, so that is not a problem either.
Both modems (fritzbox routers) are exactly the same and both lines are from the same ISP.