RT-AC56U ~200Mbps limit for bittorrent

[k0sty2u]

Hello!

I have a 500Mbps PPPoE WAN connection.

When connected via Ethernet to the router, I get ~495Mbps on speedtest, while top bittorrent download speeds vary between 190Mbps and 210Mbps (with 100-200 active connections). One CPU core is maxed out while the other one is about 25%.

QoS and Firewall are off. NAT HW acceleration is reported on.

Is there any known issue with the NAT HW acceleration and PPPoE connections? Is there anything else that could cause this limitation?

This happens with the latest 2 FWs (376.47 and 376.45).

I notices another strange behavior: the NAT HW acceleration options are sometimes Enabled/Disabled and sometimes CTF1/CTF2/Disabled. I guess this is caused by some other changes I'm fiddling with.

Thanks!

 

[kvic]

When the bit torrent issue happens, what's the Mbps you can get from speediest.net (with bit torrent stopped)?

At the moment, not sure if yours is similar to this issue.

 

[k0sty2u]

Just to clarify: this is about the speed using the bittorrent client on the PC connected to the router, and not the DownloadMaster as it does not go anywhere near these speeds.

@kvic
With bittorrent stopped, I always get ~495Mbps on speedtest. Both the connection and the router are unexpectedly stable. The longest I've had my router up is 7 days (it's still in the "shiny new toy" phase and I fiddle with it often - changing settings and rebooting). During all that time it hadn't disconnected even once and I hadn't noticed any performance degradation. It always performs like I've described in my first post: slower for bittorrent.

When I connect the PC directly to WAN (without the router) via PPPoE, I get ~450Mbps bittorrent top speed.

The same happens both for wired and wireless connections to the router. On 5GHz AC I get ~350Mbps on speedtest and ~190Mbps on bittorrent.

@kvic
I does not seem related to the issue you have linked to. I think it has something to do with the router not being able to handle more concurrent connections at top speed. I would like to find out if there is something I can do about this, or if this is just the status quo.

Thanks!

 

[kvic]

Indeed seems not the same issue though your bit torrent problem could have been caused by migration to 376.* code base of asuswrt. You mentioned the issue happened in 376.47 and 376.45. Are they simply the versions you tried?

376.44 is the first asuswrt-merlin release of 376.* codebase. If you haven't, give 374.43_2 (or its derivatives) a try. You won't miss any major functionalities for AC56U.

Cheers

 

[k0sty2u]

@kvic
Thanks for the advice. The two versions I mentioned are the only ones I have tried for Asuswrt-Merlin, since I've only got the router for less than a month. Other than this I've tried the official 3.0.0.4.374.5656 FW, but this proved very unstable regarding the WAN connection which kept going down and wouldn't come back up without manual intervention.

I'll give a try to 374.43_2 and, perhaps, even the official 3.0.0.4.376.1665 even though I'm not sure I can live without SSHD and disk spindown.
I'll post an update this weekend.

Thanks!

 

[k0sty2u]

No Luck

Hello and sorry for the delay...

I have tried both 374.43_2 and the official 376.1665 with the same results.

Could somebody else with an RT-AC56U, please, give their max bittorrent speed (on PPPoE, or other types of WAN).

Could there be a setting I'm missing?

Thanks!

 

[darkstalker]

I can max out my internet connection with torrents using the ac56u. I've got 400/400 fiber connection; regular ethernet/dhcp, connected to router, so no pppoe. Using Deluge as my client and I usually get about 40MB/s-50MB/s.

 

[longwin]

I can max out my internet connection with torrents using the ac56u. I've got 400/400 fiber connection; regular ethernet/dhcp, connected to router, so no pppoe. Using Deluge as my client and I usually get about 40MB/s-50MB/s.

May I ask you which version of firmware do you use ?

Thanks.

 

[darkstalker]

376.47, but I get the same results with every firmware since this router was released.

 

[keenism]

...probably a stupid question, but do you have a port forwarded for incoming connections? Haven't used torrents in years but I got a very nice speed boost from doing so...

 

[k0sty2u]

...probably a stupid question, but do you have a port forwarded for incoming connections? Haven't used torrents in years but I got a very nice speed boost from doing so...

Yes, the port is forwarded correctly via UPnP. Could UPnP be the cause for the speed limitation? I'll try again with it disabled and mapping the port manually, although this seems like a disadvantageous compromise.

 

[k0sty2u]

Hello!

I have finally solved it: The slowdown was caused by the Micro Transport Protocol (uTP) employed by uTorrent.
After disabling the option (Options -> Preferences -> BitTorrent -> Enable bandwidth management [uTP]), the download speed is almost flat at 500Mbps. The router CPU load is about 90% for Core 1 and 60% for Core 2.

This makes me wonder why this is happening, as this issue does not arise when I connect the PC directly to the internet, even with uTP enabled.

The first thing that comes to mind is the main difference between uTP which is UDP based and traditional BitTorrent traffic which is TCP based. This brings me back to the NAT Acceleration which seems to be slower for UDP than for TCP (that is if it supports UDP at all - I've no idea). Can somebody confirm or comment on this hypothesis?

Thanks!