Fooling a network speed limiter

hotfur · January 4, 2025, 3:44pm

Hi all,

I am using a dorm wifi network which have a global speed limit for all connected devices at 20/20Mbps. I want to bypass this limit but unfortunately do not have the admin credential for the gateway (of course). Therefore, to bypass the speed limit, the only way is to connect or emulate multiple wifi devices connected to the network, then aggregate the bandwidth somehow. I have configured a OpenWRT router (Xiaomi CR6606) in client mode (see images). Each wireless device, phy-sta[0-4] have a random MAC address, and is connected to the host network using a separate interface, named wwan[1-5]. These interfaces operate in DHCP client mode so that I have 5 IP addresses on the host network. If I managed to aggregate the bandwidth, I would be able to get close to 100/100Mbps.

Wwan[1-5] are assigned "wan" firewall zone, default policy with masquerade. First I tried to set the gateway metrics to 2 for wwan[1-5] but that didn't increase the speed. I checked ip route and here's the result:

default via 192.168.1.1 dev phy1-sta2 proto static src 192.168.1.74 metric 2
192.168.1.0/24 dev phy1-sta2 proto static scope link metric 2
Ping to 192.168.1.1 (gateway) worked on all interfaces phy1-sta[0-4] by specifying the -I option. However, ping to 1.1.1.1 worked only on phy1-sta2, where all other interfaces the packets were lost.
I tried to readjust routes by:
ip route del 192.168.1.0/24
ip route del default
ip route add default nexthop via $ip1 nexthop via $ip2 ... where $ip[1-5] are the DHCP-assigned IPs for my fake interfaces.
Ping to gateway continued to work on all interfaces phy1-sta[0-4]. However, ping to 1.1.1.1 no longer worked, all interfaces the packets were lost.

Is there any way I got to 100Mbps or more on this network? What I should try next?

moeller0 · January 4, 2025, 4:08pm

Respectfully, talk to the dorm's admin and figure out whether they offer higher access rate plans, or look at a private LTE/5G alternate internet access.

Technically your problem is that if you use X parallel links it is relatively easy to hash flows to use these different paths, but it is hard to have a single flow use the full aggregate capacity (you would need a remote point that re-aggregates these parallel streams of data).

hotfur · January 5, 2025, 4:42am

I am sorry for the question. I will try conversation again. My school was too bureaucratic last time I tried and I was tired this time.

I hope you can elaborate a little more on the technical side. You mean I don't have parallel flows (X separate internet connection from X ISP), but only 1 flow (the dorm wifi network)? Then you said I should have VPN tunnels to a remote server or something to re-aggregate bandwitdth?