I've used a TL-R600VPN with TELUS for over 6 years.  Works perfectly, no issue whatsoever.

A few years ago, Shaw came around promising 500Mbit/sec, so I tried it out.

With a single device (laptop) plugged into the Shaw gateway/modem, everything worked as expected. 500Mbit throughput, no packet loss, very low latency.

As soon as I plugged the TL-R600VPN into the exact same port, latency climbs to 8000ms+, packet loss is 90%+, throughput drops to dial-up speeds, and generally speaking, it's not usable.

Removed the TL-R600VPN, go back to a single device (laptop) and everything works perfectly.

Have the Shaw tech come out 3 times in a week, he can't figure out what's wrong.  So, I cancel the service, stay with TELUS, and everything is fine.

Fast forward to October 2025, now Rogers is coming around offering up to 2 Gbit. I choose 1 Gbit. All their services in my area are 1000dn/200up. No problem.

They promise all new hardware, all new modem, no possible way the same issue will happen.

Ok, plug in a single device, everything works as expected.  Measured 1000dn/200up, over several days of tests.

Then.. I plug in the TL-R600VPN in the exact same place as the single device. same port. I just unplug from TELUS, plug into Rogers, re-DHCP, it gets a new public/WAN address, and immediately the same problem reappears; latency climbs to 8000ms+, packet loss is 90%+, throughput drops to dial-up speeds, and generally speaking, it's not usable.

I pull the TL-R600VPN, switch back to the single device, everything works perfectly.

Both the TELUS and Rogers devices are in BRIDGE MODE.  The TL-R600VPN gets the public WAN IP directly from the ISP.   The TL-R600VPN always (instantly) gets an IP address, with both ISPs, no issue there.  Resetting any/all devices involved to factory settings produces the same results.  The firmware in the TL-R600VPN is the latest. (4.0.4 Build 20200313 Rel.41831)

So what this comes down to, for me, is that the TL-R600VPN works perfectly with TELUS, but does not work with Shaw/Rogers.

Has anyone else seen this exact issue, and knows the surgical solution?  Let me know if you do. I only have 2 weeks to cancel the Rogers service, and would like to figure out what's wrong before then. My TELUS service is only 150Mbit/sec, so it would be a huge upgrade to switch to gigabit.