Upgraded from AC87U to AX6000, measurable latency increase

DAOWAce

New Around Here
I don't see much talk about the AX6000 on these forums; which makes me feel like I've purchased a dud after finally testing the router out.

Here's the simplest way I can show the issue:

AC87U:



AX6000:



The AX6000 is consistently 2-3ms higher at baseline, and a bizarre 4-5x (30-40ms) higher during upload. EDIT: Upload is due to adaptive QoS being worse, see next post.

This does translate into actual applications, ie; traceroute monitoring and games' built-in ping feature. Higher minimums and averages, potentially jitter but that's harder to test.


I have ran these tests multiple times, rebooted the devices multiple times.

I have them configured as identically as I can. EDIT: I have even tested at default settings (see next post).

Updating to Merlin firmware did not change anything about this issue. (and actually decreased speeds with QoS enabled for some reason)


As I primarily play online games, a latency increase is the worst thing that can happen. Throughput is the least of my concern, and it's quite ironic that for a heavily 'gaming' focused router, the AX6000 is objectively worse than the 87U which has underpowered hardware and completely faulty wireless.

Unfortunately, I have to switch from the 87U because of its crippling issues. The router itself just bogs down when certain interactions happen with other devices on the network (notably traffic routed through a wireless AP) and I'm completely sick of it.


Does anyone have any insight into this bizarre issue? I doubt ASUS will give one damn if I contact them about it (already submitted in-router bug report), though I'm not somebody who can get around entry level CSR's.
 
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bbunge

Part of the Furniture
The AX6000 is the second most recommended router after the AX86U. What happens with QOS disabled? Try QOS with auto and manual settings. Speed test with a wired PC connected to LAN port 1.
 

OzarkEdge

Part of the Furniture
I have them configured as identically as I can.

Maybe the new router doesn't benefit from a configuration identical to the old router.

OE
 

DAOWAce

New Around Here
The AX6000 is the second most recommended router after the AX86U. What happens with QOS disabled? Try QOS with auto and manual settings. Speed test with a wired PC connected to LAN port 1.



Having adaptive QoS enabled seems to be causing that 4-5x upload latency increase during the test. Setting bandwidth to auto doubles it (and seems to just not cap at all). "Cake" (whatever that is) does this as well. I was using Adaptive on the AC87U without this issue.

Regardless, I've temporarily disabled QoS due to the latency and the drastic speed decrease, but I don't want to leave it like that because, well, it's QoS, and I share the internet with a household and a dozen other network connected devices. 'Traditional' QoS isn't what I want to deal with managing, and while it does still slow the connection (208 from 220), it's definitely not as bad as adaptive and doesn't have that upload latency issue. Worst case I get frustrated enough to start using it..


However, the minimum latency is the same, and this is what my real issue is with the router 'upgrade'. I know I'm fussing about 2-3ms, but as a competitive gamer who's tried to reduce their latency as much as possible over the last 2 decades (and was one of the first to report on that Puma6 chipset issue), having it increase just from a router swap (to a "gaming" one no less) is a huge slap in the face.

I can also confirm it's not an issue with the router management for LAN devices, as the built-in speedtest in the AX6000 shows the latency increase as well.


PS: The AC87U Merlin firmware had more options for QoS, like codel and fq_codel, but attempting to use those over sfq resulted in a heavily crippled connection. Unsure why.


Maybe the new router doesn't benefit from a configuration identical to the old router.

TLDR: My config isn't affecting this latency issue.

Explanation: It's mostly things related to LAN devices, port forwarding, etc. Management things I've setup over the years of using, well, the internet behind a router. Always carried over most of these settings from previous routers, which I've gone through 4 in the last 23 years.

Unless there's some bizarre bug with the firmware, I can't think of any of these settings causing such an issue to present itself.

But, just to rule it out, I reset to factory defaults and...



No change to minimum latency, but now download latency increased, and it was varying wildly and I saw it peak as high as 544ms with packet loss on the router's hop. This didn't happen with my config even with QoS disabled (possibly due to bandwidth monitor settings and prioritization of my device, which are oddly separate from QoS settings).

Code:
|------------------------------------------------------------------------------------------|

|                                      WinMTR statistics                                   |

|                       Host              -   %  | Sent | Recv | Best | Avrg | Wrst | Last |

|------------------------------------------------|------|------|------|------|------|------|

|                          GT-AX6000-9F98 -    5 |  100 |   95 |    0 |    0 |    1 |    0 |

|                           xxx.xxx.xx.xx -    2 |  100 |   98 |    8 |   21 |   85 |    9 |

|                           67.59.235.188 -    1 |  100 |   99 |    8 |   23 |   85 |   11 |

|          ool-4353f002.dyn.optonline.net -    1 |  100 |   99 |    9 |   25 |   88 |   12 |

|                           67.59.239.119 -    2 |  100 |   98 |   10 |   24 |   90 |   10 |

|                             64.15.5.253 -    2 |  100 |   98 |   12 |   27 |   90 |   14 |

|              451be0e7.cst.lightpath.net -    1 |  100 |   99 |   11 |   27 |  109 |   14 |

|                            167.206.15.9 -   80 |  100 |   20 |   11 |   21 |   88 |   11 |

|                   No response from host -  100 |  100 |    0 |    0 |    0 |    0 |    0 |

|________________________________________________|______|______|______|______|______|______|

So, unfortunately, it's not my config causing the issues (and if anything it's helping them!).
 

drinkingbird

Very Senior Member
Just a comment about latency increasing during uploads, when you saturate your bandwidth, either upload or download, latency will increase, regardless of your router. Unless you set up some sort of QOS to allow your ping tests to get a dedicated allocation of traffic, but QOS will increase your latency a bit across the board....

From your table above, looks like you're experiencing regular packet loss. Again this can be caused by saturating either upload or download but ping and latency tests should not do that. Perhaps your router has a bad port, or is more prone to interference from something nearby than your old one was. Or, the architecture is just such that it has an extra couple ms to get through the CPU.
 

drinkingbird

Very Senior Member
I don't see much talk about the AX6000 on these forums; which makes me feel like I've purchased a dud after finally testing the router out.

Couple thoughts/things to try

The new router may simply be de-prioritizing ICMP traffic automatically, or not processing it in hardware.
The new router may be getting a different IP from your ISP which routes over a different path or hits a router on their end that is either overloaded or de-prioritizes ICMP traffic. Since the MAC is stored on their end, each time you switch routers, you'll get the IP that router had previously (usually, depends on the ISP).
If this is what is happening, spoof the WAN MAC from the old router onto the WAN of the new router. Should hopefully grab the same IP, see if that changes anything.

You can try doing TCP ping to bypass any ICMP limitations (if you don't have a linux box available you can get utilities for Windows to do this) and see if the results are more in line. Just find an IP on the internet that responds to it with consistent latency and test via both routers, should get identical results.

To try and narrow down where the latency increase is:
Ping the router LAN IP from a wired computer. Both routers should be 1msec or less.
Ping your WAN IP from the same computer via both routers. This should be in the 1-2 msec range from wired, likely 1msec or less.
Ping the ISP gateway (the default gateway reported in the router GUI) from the same PC via both routers. The results should be comparable for both routers.
Ping an IP on the internet like 4.2.2.6 or something, both routers should have similar results.
SSH into the router CLIs and ping the ISP gateway and 4.2.2.6 or whatever from there too.
Not sure if the Asus and/or ISP gateway will respond to TCP pings but if it does, better to use that to avoid any ICMP prioritization/processing issues which would be mostly cosmetic and not impact your actual performance.

For simplicity, if your ISP supports IPv6, make sure to ping only one or the other, probably easiest to stick with v4 for testing.

Based on that can narrow down a bit more where the issue lies.
 
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