RT-AX86U Pro PPPoE Limitations

[geralds34]

I have Bell Fiber to the house, on a symmetric 3G plan. Testing speeds on the HH4000, its reports speeds of 3.2 down and up

If I connect the AX86U Pro to the 10G port of the HH4000 and it is configured as a router, speeds test from the Asus report 2336.92 down and 2352.84 up , but this config is then double NAT .

Reconfig the AX86U Pro to use PPPoE as the WAN connection type, bypassing the HH4000 to the extent possible and eliminate double NAT, I see speeds of 2338.18 down and 1537.76 up.


Is the lower upload speed when configure to use PPPoE a limitation of the AX86U Pro?


Do I think the lower upload speed has any effect on the family, no, but curious what the bottleneck is, or if I have missed something in my setup.
Using Asus Firmware Version: 3.0.0.6.102_34349

 

[degrub]

Running the router based speed test may be consuming CPU that affects the result. Try with a 2,5G client into a 2,5G port on the router. Also, 2.3 Gb/s would be about the max possible for a 2.5 Gb/s port given packet overheads. Other threads have reported issues with PPPoe upload rates. search the threads for PPPoe

 

[bbunge]

What do you have the MTU set for? 1492 is the default for PPPoE. If you have it set to 1500, which is the default for Ethernet, the upload may be slow due to upstream fragmentation. Set the MTU for 1492 or lower.

 

[geralds34]

What do you have the MTU set for? 1492 is the default for PPPoE. If you have it set to 1500, which is the default for Ethernet, the upload may be slow due to upstream fragmentation. Set the MTU for 1492 or lower.

1492 seems to be default when using PPPoE. From the WAN Tab:

 

[gp-se]

I also use Bell, but I'm on 1.5 down, 940 up and using the Gigahub. I experience the same issue, using the Lan ports (gigabit) I get 940 down, 750 up. Wi-Fi even worse, 750 down, 500 up. Hardwired directly to the Gigahub gives me full speeds, so my connection is capable of delivering the speeds.

 

[bbunge]

Reading through several posts on this forum and a couple of other sites, it seems that Asus routers are limited in what they can do over PPPoE. The limitation appears to be with upload bandwidth which is likely due to the router having to fragment the 1500 byte packet size of the LAN (Ethernet default) down to the 1492 byte packet of PPPoE.
One thing you could try is to lower the MTU of your client. I checked my Mac and there is a setting to change the default MTU. Other OSes should have the same or similar setting. This is just a theory on my part as I do not have PPPoE. I do remember discussion of MTU from a networking class I took years ago. The theory, at the time, to improve throughput was to lower MTU to avoid downstream fragmentation and not raise it.
I also read a couple of posts about using the router behind a HH4000 and using advanced DMZ settings.

 

[RMerlin]

Reading through several posts on this forum and a couple of other sites, it seems that Asus routers are limited in what they can do over PPPoE. The limitation appears to be with upload bandwidth which is likely due to the router having to fragment the 1500 byte packet size of the LAN (Ethernet default) down to the 1492 byte packet of PPPoE

There's no packet fragmentation issue. 1492 is the standard for PPPoE, leaving 8 bytes for the overhead - it actually ensures that there won't be any fragmentation.

I have no issue hitting the full speed of my own Gigabit connection over PPPoE here:

 

[degrub]

@RMerlin , so what do you think may be the issue that we repeatedly see with upload bandwidth "testing" ? under powered router ?

 

[Tech9]

I have no issue hitting the full speed

BCM4916 vs BCM4912 perhaps?

 

[RMerlin]

BCM4916 vs BCM4912 perhaps?

My previous GT-AXE16000 had no problem maxxing out my 1 Gbps FTTH either.

@RMerlin , so what do you think may be the issue that we repeatedly see with upload bandwidth "testing" ? under powered router ?

I see different people complaining about issues, none of them providing enough details to determine what is going on for each of them - they may each all have different reasons for their limitations. Misconfigured QoS. Testing from wifi instead of Ethernet. Testing from the router instead of from a wired client. ISP issue. Other traffic on their network affecting throughput. And so on - too many variables.

All I can say for a fact is that the hardware can definitely hit over 1 Gbps with PPPoE.