[RT-AC68U] Getting 1Gbps WAN-LAN throughput

[Bloodred217]

Hello!

I've been using an Asus RT-AC68U router for about a year now and it has been handling my 500Mbps connection flawlessly while running Merlin 378.51.

Recently I have upgraded to a 1Gbps connection (it was actually cheaper, yeah) and my trusty AC68U doesn't seem to manage getting much over 700-750Mbps WAN-LAN throughput. That's pretty good, of course, but I'd still like to get full speed and when I bought it I remember seeing a lot of users reporting results over 950Mbps (they were using PPPoE though, my connection is regular Ethernet with DHCP from my ONT). If I start a speed test (my ISP's or speedtest.net) I see Core 1 on the router's web interface hitting 100% load in the 700-750Mbps range, so I'm quite sure the router is the bottleneck and not something else. I don't have any fancy services running on it (VPN, USB file sharing, QoS, etc.), all it does is NAT/firewall and DNS filter using OpenDNS for a single device on the network (it's offline, not the machine I'm testing on).

Since other people have been able to achieve 950Mbps+ speeds on PPPoE, I imagine getting the same kind of numbers using plain DHCP should also be possible. I did notice that my configuration shows that only CTF is enabled. I did a factory reset and only configured the bare minimum for Internet connectivity, which is just MAC clone, and this enabled both CTF and FA, but performance remained the same and Core 1 still hit 100% load during tests.

Is there anything I can do regarding configuring the AC68U for better performance? So far I've tried both the latest firmware from Merlin (380.57) and Asus, but these firmwares actually showed much worse performance, even as low as 250-300Mbps with CTF + FA with overall higher CPU load (Core 1 hitting 100% once again and Core 2 above 50%, it was idle on Merlin 378.51).

I wouldn't want to get a new router, this one has been exceptionally stable and well behaved so far, if I could get a bit better performance out of it I'd have no reason to upgrade until it breaks. Is OC a viable solution while maintaining reliability? It's currently running 800/666MHz and I haven't tried OCing yet, if other options are available I'd rather do something else first. It came with CFE 1.0.2.0. Would it require extra cooling for that?

I'd appreciate any input on the subject. Thanks!

 

[gatorback]

What is the Asus stock firmware WAN speed test results?

 

[Bloodred217]

The Asus firmware version I flashed was 3.0.0.4.380.1031 and I was getting results in the 250-300Mbps range. I tried connecting my PC to the ONT directly to confirm that it wasn't because of the connection and got 870-880Mbps, so it was definitely the router limiting speed.

In terms of configuration, all I did was go through the initial wizard and set the MAC address clone, everything else was at default settings. I also restored to factory defaults (from the web UI) after I flashed the Asus FW.

The behavior was somewhat odd though, I think I may have stumbled upon a bug. The PC I'm testing from isn't the one having its MAC address cloned (WAN MAC != PC MAC). The MAC address is actually from an old machine that is no longer in use. Since I was also connecting my PC directly to the ONT to check speed without a router, I had also overridden the MAC on the PC's NIC (WAN MAC == PC MAC). This seems to cause terrible performance, i.e. ~300Mbps. This is easily reproducible on 378.51 as well. If the test PC has the same MAC as the router's WAN interface, performance is terrible. For this reason, the results I got on the newest Merlin and Asus FWs are probably invalid and I'll have to find the time to retest. The poor performance persists even after I revert the PC to using its own MAC. Simply waiting a while after changing the PC MAC back to the original or rebooting the router seems to fix it. Is there a good reason for this to happen? When this is going on I see Core 1 at 100% load even around ~300Mbps. Could this be interfering with something, the HW acceleration maybe?

 

[Lislet]

Try putting the router in ap mode. I had the same problem hitting wan/lan speeds of around 200/300mbps. Tried to change hw acceleration and other settings for hours, then i resolved using the isp router/modem combi for doing the dhcp and set the asus as ap. Now i get 960mbps up & 960mbps down.

 

[rickysuper]

My AC68u had max. download speed 7xxmbps and upload was 9xxmbps with my 1G broadband and default router settings. When direct plug the cable to my computer without the AC68U was 8xxmbps and upload was 9xxmbps. I think 7xxmbps was the max speed of the AC68u.

Anyone can set faster download speed as my router settings was the default DHCP, MTU1460, HW acceralation auto and jumbo frame was enabled. Disable jumbo frame gains about 40mbps of download speed. Firmware version was Merlin 380-56_2

Thanks

 

[Odkrys]

well, when I used Gigabit internet 2month ago (now I am using Half-Gigabit because my laptop and smartphone wireless are just supporting 2x2 so really don't need 1 Gigabit), with AC66R - 600mhz 1core - I hadn't any problem. always I got 900+/900+ on the test.

I don't think its router's bottleneck.

 

[rickysuper]

well, when I used Gigabit internet 2month ago (now I am using Half-Gigabit because my laptop and smartphone wireless are just supporting 2x2 so really don't need 1 Gigabit), with AC66R - 600mhz 1core - I hadn't any problem. always I got 900+/900+ on the test.

I don't think its router's bottleneck.

According to router review AC66 has faster WAN to LAN speed than AC68, it can reach to about 8xxmbps or may be a little bit faster.

 

[doczenith1]

I typically see around 860 down and 940 up. All AiProtection options enabled and no Qos. NAT acceleration is set to Auto and it is running in CTF (Cut Through Forwarding) mode. When running the speedtest CPU core 1 will be at 100% and core 2 will be around 5%. Jumbo frames are disabled.

 

[doczenith1]

With the AiProtection stuff turned off Flow Acceleration gets enabled in addition to CTF. This reduces the CPU load to less than 10% and I see speeds around 945 up and down.

 

[sfx2000]

Recently I have upgraded to a 1Gbps connection (it was actually cheaper, yeah) and my trusty AC68U doesn't seem to manage getting much over 700-750Mbps WAN-LAN throughput. That's pretty good, of course, but I'd still like to get full speed and when I bought it I remember seeing a lot of users reporting results over 950Mbps (they were using PPPoE though, my connection is regular Ethernet with DHCP from my ONT

Funny thing - once one gets above about 500Mbs WAN connections, most folks can't tell unless they're doing very specific benchmarks to measure performance - the major improvement with these Gigabit home links is not the downlink, but the uplink performance, which makes things quite a bit more responsive, esp. on fiber as it can be a bit better with uplink compared to xDSL or Cable (or LTE for that matter for those that have that as an only option)...

I wouldn't worry about it too much - your connection is faster than probably 90 percent of the forum subscribers here

 

[huygens_25]

I did some tests over the weekend to see the routing speed of my RT-AC68U. I've been using iperf3 with 2 machines: one on the WAN interface the other on the LAN interface. Previously I had measured when both machines where on the LAN and I could get around 950Mb/s in TCP or UDP. But when using the router in between (with everything disable apart from NAT/Firewall and port transfer) I get this:

• CTF+FA are activated:
  • I get close to 850Mb/s using TCP and about 0% CPU usage, the ping to an internet host is not affected during the test!
    
  • I get around 250Mb/s using UDP with 1 core at 100% usage, ping is affected (+30ms avg with spikes up to 400ms)
    
  • When I do simultaneous down-/up-load, TCP bandwidth is slightly impacted (around 750-800Mb/s per stream, so around 1500-1600Mb/s simultaneous), whereas UDP is almost halved about 180Mb/s each (360Mb/s simultaneous)
• CTF-only activated (with Adaptive QoS with manual bandwidth set both ways to 1024Mb/s)
  • I get close to 750Mb/s using TCP but about 100% on 1 core, the ping to an internet host is affected during the test (30ms avg with no real spike)!
  • I get around 250Mb/s using UDP with 1 core at 100% usage, ping is affected
  • When I do simultaneous down-/up-load, TCP bandwidth is slightly impacted (around 750-800Mb/s per stream, so around 1500-1600Mb/s simultaneous), whereas UDP is almost halved about 180Mb/s each (360Mb/s simultaneous)
• Software mode (with Traditional QoS with manual bandwidth set both ways to 1024Mb/s)
  • I get close to 600Mb/s using TCP but about 100% on 1 core, the ping to an internet host is affected during the test (30ms avg with no real spike)!
  • I get around 180-200Mb/s using UDP with 1 core at 100% usage, ping is affected
  • When I do simultaneous down-/up-load, TCP bandwidth is not really impacted (about 1200Mb/s simult.), whereas UDP is almost halved about 150Mb/s each (300Mb/s simultaneous)

In UDP, there was no to a few packet loss, and a handful of out of order packet, so pretty good in all cases.
I was running on latest AsusWRT Firmware 3.0.0.4.380_3831 (kernel 2.6.36), and both machines where running Ubuntu 16.04.1 (kernel 4.4).
I don't know why the UDP tests were so bad in comparison to TCP. I understand that perhaps the H/W acceleration are only for TCP, but when using software mode I have almost 3x better bandwidth in TCP than in UDP, that I don't understand. But I have no more time to investigate that.

I think you should make sure that you have both CTF+FA in your "Switch Control" tab, this should enable you with the best throughput and lowest latency. Then how did you setup your test, which tool did you use to measure bandwidth and against which host?

Anyway, in the end what is important is what do you need your 1Gb/s for? Some applications are bandwidth sensitive while other latency sensitive. For example VoIP would be latency sensitive while downloading the latest Ubuntu ISO would be bandwidth sensitive. If your need is a good balance of both in mainly TCP then CTF+FA or CTF-only seems the best options. For UDP, it seems that CTF+FA could achieve good bandwidth but the latency was the most erratic. In the other modes when QoS is activated, the latency on UDP behaves much better, so if you plan on using many UDP applications and that latency is important, I would favor the use of Adaptive or potentially Traditional QoS.

Anyway it was just for fun. I'm limited in my area to at best 300Mb/s down and 150Mb/s up depending on the provider. At the moment I have way less than both (120 down and 6 up), so I'm not hitting any limit whatever option I choose

 

[bartoszbruhn]

Hello, I new here, so Welcome.
I have just update my Internet from 100 to 600 (FTTH) and I'm using RT68U with AsusWRT Firmware 3.0.0.4.380_3831. I have issue with WAN_LAN throughput.
General settings: add hard drive via USB, set FTP server, also with external open Ausu domain AiDisk. In WiFi 1-5 additional devices (both 2.4GHz and 5GHz). Firewall On, NAT off, AiProtection off.
Of course WiFI devices do not make any impact, during tests do not use Router FTP.
First case: (All value in Mb/s)
QoS disable, CTF+FA are activated.
After apply settings, and auto restart of router I get full 600/60 bandwidth. In aprx. 10 min later it's drops to just 350-450/60 bandwidth. I cant stand why it's happening. I can imagin, that some service are lunching with some delay and maybe that effectives, but which services.
Secend case:
QoS enable, CTF are activated.
After apply settings, and auto restart of router I get full 600/60 bandwidth. 10 min laterit's drops to just 350-450/60 bandwidth and the even up to 180-200.

Can someone explain me what is happening, and how to fix this.
My PC have 1Gb MSI Killer Ethernet port.

 

[huygens_25]

Hi bartoszbruhn

Could you explain to me what you mean by "NAT off". NAT cannot be off unless you use public IP addresses on your LAN, but I doubt it. Do you mean that you disabled NAT acceleration?

How did you your benchmarking? Which tool did you use? Are you sure the drop in bandwidth is due to the router and not your client computer? Do you use Windows and then which version?

 

[bartoszbruhn]

Thanks for Your attention. I'm not fornt of my PC so dont remember NAT settings, but your right, its should be ON and I'm using NAT acceleration as above.

First case: (All value in Mb/s)
QoS disable, CTF+FA are activated.
Secend case:
QoS enable, CTF are activated.

I use WIN 10 for test, Chrome and speedtest website. As I post after restart Ruter I have a full bandwidth. Ten min later just half of them.
WAN->RUTER->PC Client (use Killer Ethernet, which is on my motherboard.
Maybe some WAN settings are wrong. I have put different MAC address than default.

Next what I will try is to lunch Win 10 in Safe mode with network and then try hit.

 

[huygens_25]

I do not trust too much those speedtest websites. But if you have no other means, then try this one: http://www.dslreports.com/speedtest

This site is not too bad, it provides lots of control on the test and good feedback (including how the latency is impacted by the bandwidth, aka bufferbloat).

Try with this website, after reboot, after 10min and then after several hours or days. Go to the preferences (http://www.dslreports.com/speedtest/preferences) and select your closest server manually (select the same list for each run). It has an option for 1Gbps line, check it (you might need to register to use that particular option, it is not mandatory if you think your harddisk or SSD is fast enough). Look at the other options if you wish. But take care to select the same set of options for each run.

 

[bartoszbruhn]

I understund your trust or not trust in speedtest.

But i start download game over 60 GB.
At the begining it was over 60Mb/s, and that is cool, but then its drop to 30 Mb/s and finally to 20 Mb/s. I use Polish site speedtest.pl and its quite good.
I'm still thinking that router is bottleneck or connection settings WAN->Router or just my Ethernet in PC.
But also with QoS Adaptive enabled, speed test on iPhone drops from 100MB(cant take more) to 50-60MB. But upload still was on 60MB.

Look, problem simillar to me:
https://vip.asus.com/forum/view.asp...39&board_id=11&model=RT-AC66U&page=1&count=14

Now I have connected via WiFI 2 laptops, 1 Phone, TV. All devices runing twitch stream and you tube play in the same time.
On my LAN PC I'm download over 50Mb/s form Origin and play CS:GO without any lags.
Everything works fine, still wiating for two devaices, maybe, somewhere there is a problem.

You will not belive.
I can connect many devices in one time and everthing is perfect.
But when I connect Samsung Android phone. K3(not sure model) bandwidth drops x2 on LAN PC.
No QoS, nothing, just this. When I disconnect phone from Network, restart and all is good. Also when ruter do not see phone for a while in network, bandwidth back to over 600/60 MB/s.

Why?

 

[huygens_25]

I understund your trust or not trust in speedtest.

But i start download game over 60 GB.
At the begining it was over 60Mb/s, and that is cool, but then its drop to 30 Mb/s and finally to 20 Mb/s. I use Polish site speedtest.pl and its quite good.
I'm still thinking that router is bottleneck or connection settings WAN->Router or just my Ethernet in PC.
But also with QoS Adaptive enabled, speed test on iPhone drops from 100MB(cant take more) to 50-60MB. But upload still was on 60MB.

Sustaining download especially when done over TCP (e.g. HTTP/HTTPS or FTP) is something that clearly depends of many factor on the network: latency (and hence distance), packet loss, buffer sizes, congestion, and the TCP algorithms chosen on both end of the stream regarding flow and congestion control, and how your OS is parametered. This is very complex to analyse. What I can tell you is that for 2 Linux machines which I have both carefully configured to support 1Gbps throughput and putting just the RT-AC68U in between (no other network device and no other network activity), I can sustain throughput at about 600Mbps using traditional QoS (so no NAT aceleration, using software NAT). So the router should be fast enough. Of course, if you have multiple devices, if your ISP has some flow controls or congestion problems or quality problems (dropped packets, etc.) That can all affect your throughput. And then it is not limited to your ISP, but how your ISP is interconnected to the network of your game service, this can also impact your throughput.

I can only tell you that RT-AC68U can support 600/60Mb/s. If you have lower bandwidth this could come from anything between the 2 ends of the network link.

PS: usually ISP have good interconnection with the networks of those "speedtest" providers. This is a good trick for them so that people think they have the 600/60 they bought, but maybe they can only achieve 60/6 if they were able to do the speedtest with youtube servers. Check for example https://fast.com/ it is a speedtest (only for download) using netflix servers, on some ISP the maximum bandwidth you get is much lower than on speedtest.net.

I can connect many devices in one time and everthing is perfect.
But when I connect Samsung Android phone. K3(not sure model) bandwidth drops x2 on LAN PC.
No QoS, nothing, just this. When I disconnect phone from Network, restart and all is good.

Do you mean that your PC which is connected with Ethernet cable is impacted by the connection of your Android phone on the WiFi? Is your phone using a lot of bandwidth when connected? We have an Andoird phone and an iPhone, but whether or not they are connected usually does not impact the bandwidth of my PC which is connected with cable. Unless of course we would use a lot of bandwidth with our phone, which we don't. Sorry I can't help you on that topic. This looks like another issue, perhaps you should start another forum thread for just this problem.

 

[bartoszbruhn]

Phone is not use bandwidth at all(router transfer monitor = ~0.5 MB). I do not use Android phone, but try find out .
But also that phone can't transfer 300MB/s. Will do new topic, but before will do some more tests on Phone.