ASUS RT AC68U - Android Tethering Through 5G Handset Challenge

[idea1979]

Context : I don’t have wired internet connection and I am using 5G Android mobile for internet access. I have routed 5G android mobile connectivity through USB of ASUS RT AC68U router for further wired consumption.

Problem : At 5G mobile, I get 700 MBPS speed. However, after tethering android mobile through USB 3.0 of ASUS RT AC68U, I get max 150 MBPS (Either WiFi or Wired connection). I have ensured, I am using USB 3.0 cable to connect mobile to router. Cable has 10 GBPS capacity.

Surprisingly, When I connect laptop to 5G Android mobile directly through USB tethering (no router in loop), I easily get 300+ MBPS.

Naturally, router is – somehow limiting speed to max 150 MBPS when USB android tethering is used and in a way acting as bottle neck. Is there any way, I can take out this bottle neck and get at least 300.

More Info :

• ASUS RT AC68U has latest Merlin and Reset was done after merlin install. RT-AC68U 386.3_2
• Disabled all unwanted services like Media server, FTP, File sharing Etc.
• Router CPU Load is hardly 20-30% at peak
• Router Memory is more than 50% free.
• USB 2 and USB 3 gives same speed of max 150 MBPS
• My mobile has latest firmware (though it should not matter)

So is there any way you can suggest to take care of this bottleneck or increase speed through tethering mobile through USB 3.0 of ASUS RT AC68U? May be through some script or changing some hidden USB settings?. I do expect minimum 300 MBPS as I am getting it when I loop out router by directly usb tethering mobile to PC/Laptop.



Thanks for your help in advance.

 

[L&LD]

Welcome to the forums @idea1979.

I do not believe the router has the CPU capabilities to do more when tethered via USB.

Your PC or laptop has much more performance than the 800 to 1000 MHz CPUs the router has.

If you want the fastest speeds possible via USB tethering, you need a more current router design. Preferably with equal or greater than 1.8GHz dual-core capabilities.

 

[idea1979]

Thank you for taking out time for quick revert.

I am not sure how powerful CPU is. However, router has handful of features being a gaming router. Above all, i have disabled all other unwanted features and only one user being in testing mode.

I did a quick SSH and here are details about CPU (It is dual core and 1Ghz)

Processor : ARMv7 Processor rev 0 (v7l)
processor : 0
BogoMIPS : 1998.84

processor : 1
BogoMIPS : 1998.84

Features : swp half thumb fastmult edsp
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x3
CPU part : 0xc09
CPU revision : 0

Hardware : Northstar Prototype
Revision : 0000
Serial : 0000000000000000

Memory :

MemTotal: 255684 kB
MemFree: 181836 kB
Buffers: 1992 kB
Cached: 11664 kB
SwapCached: 0 kB
Active: 27996 kB
Inactive: 7292 kB
Active(anon): 22008 kB
Inactive(anon): 684 kB
Active(file): 5988 kB
Inactive(file): 6608 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 0 kB
Writeback: 0 kB
AnonPages: 21632 kB
Mapped: 7356 kB
Shmem: 1060 kB
Slab: 22372 kB
SReclaimable: 2260 kB
SUnreclaim: 20112 kB
KernelStack: 808 kB
PageTables: 1012 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 127840 kB
Committed_AS: 39152 kB
VmallocTotal: 516096 kB
VmallocUsed: 18008 kB
VmallocChunk: 444380 kB

Would it be CPU causing bottleneck?

 

[L&LD]

Unless someone else confirms otherwise, I think the issue is still the quoted part of my original message below.

I do not believe the router has the CPU capabilities to do more when tethered via USB.

 

[idea1979]

Thank you for your revert.

I am open for all possibilities to explore. CPU could be contributing as well.

Seeking out to all experts for their opinion to settle this challenge.

Thanks

 

[RangerZ]

I support @L&LD and offer this post which the OP indicates less than expected speeds. I have notes similar (slow, but in line with your results) performance in my reply #18 with a pair of AC-RT1900p (RT-AC68u family) devices.

Have you tried setting the router up in "Repeater" mode and connecting to the phones hot spot? Honestly not expecting it to be much faster, based upon my tests, but it may reduce some "overhead" and any USB inefficiencies.

Others may be curious about how exactly you configured your tether.

 

[idea1979]

I support @L&LD and offer this post which the OP indicates less than expected speeds. I have notes similar (slow, but in line with your results) performance in my reply #18 with a pair of AC-RT1900p (RT-AC68u family) devices.

Have you tried setting the router up in "Repeater" mode and connecting to the phones hot spot? Honestly not expecting it to be much faster, based upon my tests, but it may reduce some "overhead" and any USB inefficiencies.

Others may be curious about how exactly you configured your tether.

Thanks for revert.

I havent tried repeater mode+mobile hotspot considering simple fact that if i take hotspot from mobile to any other device, speed is medicore.

ASUS RT AC68U support Android tethering through USB. You just need to enable it as WAN in router setting.

 

[idea1979]

I am planning following steps

1. Finding a spot wherein 5G speed is more than 700MBPS ( i get same speed at my home and through Android tethering through ASUS RT AC68U ) and check if speed goes beyond 150MBPS. This will be done with existing setup using 5G Mobile and ASUS RT AC68U on merlin.
2. I will change firmware from merlin to Asus and check if speed goes up beyond 150MBPS with assumption merlin is causing bottleneck.
3. Try to get hold of more powerful asus router and check if i still get 150MBPS. If speed goes beyond 150MBPS means ASUS RT AC68U has some constrains.


Seeking out to all experts for their opinion to settle this challenge.

 

[idea1979]

Thank you for your revert.

I am open for all possibilities to explore. CPU could be contributing as well.

Seeking out to all experts for their opinion to settle this challenge.

Thanks

 

[Network1]

You might try changing the default TTL on the router to say 65 if your phone is using 64.

 

[drinkingbird]

You might try changing the default TTL on the router to say 65 if your phone is using 64.

That's usually to try and overcome tethering speed caps imposed by the provider, but most have figured out that trick and eliminated the workaround, also if OP is able to get higher speed tethering to a PC that isn't the issue anyway. But the post is from last year so they probably figured it out by now.

 

[Network1]

Happy my provider hasn't figured it out

 

[drinkingbird]

Happy my provider hasn't figured it out

Visible has even taken it a step further, if they determine that you are abusing tethering or hotspot, they cut you to like 256K for all data (even mobile) for the rest of the month as a warning. They have unlimited hotspot with 5M cap and people use an android app to get around it (app makes it look like traffic is coming from the phone as normal mobile data). The TTL trick used to work for them but they fixed that, and a couple other workarounds also. Since they can't fix this one, they just cap your entire mobile data speed if you break their rules.

 

[sfx2000]

Surprisingly, When I connect laptop to 5G Android mobile directly through USB tethering (no router in loop), I easily get 300+ MBPS.

Naturally, router is – somehow limiting speed to max 150 MBPS when USB android tethering is used and in a way acting as bottle neck. Is there any way, I can take out this bottle neck and get at least 300.

MTU and MSS - when tethering over USB on 4G/5G - MTU can get mismatched, so packets get fragmented...

Setting MaxMTU to 1428 usually helps...

 

[drinkingbird]

MTU and MSS - when tethering over USB on 4G/5G - MTU can get mismatched, so packets get fragmented...

Setting MaxMTU to 1428 usually helps...

Makes sense, though if there was heavy fragmentation I'd expect the CPU to be pegged. Though not sure if that screen shot was showing a speed test at the beginning or not.

If IPv6 ever does take off, at least PMTUD will finally work (hopefully).

 

[simpelekees]

Im gonna test this on a cheap second hand asus ac68u i found. Maybe with the Merlin firmware and maxMTU settings.

 

[sfx2000]

Surprisingly, When I connect laptop to 5G Android mobile directly through USB tethering (no router in loop), I easily get 300+ MBPS.

Naturally, router is – somehow limiting speed to max 150 MBPS when USB android tethering is used and in a way acting as bottle neck. Is there any way, I can take out this bottle neck and get at least 300.

Just out of curiosity, what model/vendor is the phone?

Anyways - check on your laptop when tethering - is it a USB Network Device, or is it a USB Serial Device (COMM port emulation).

I've seen similar behavior on OpenWRT, and in every case, it was how the device enumerated when connected via USB - as a serial device, it's actually the phone that is the issue, not the router...

 

[simpelekees]

I could only get it working through repeater mode. As expected, my Nokia 8.1 wasn't supported. USB tethering didn't work.