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RT-AC68U QoS and questions about latest Merlin

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[Confusingly, a pair of RT-AC68U are badged on the front AC1900]

I'm asking this specifically about the RT-AC68U; specific because the router is quite old now
and things evolve. The connection is FTTP 110/21.

This context is the master mesh node, running a wireless bridge to an identical router in another room.
This router is not responsible for pppoe or anything like that. It's in a static WAN
configuration and runs NAT+firewall. The WAN facing ip is a real routable ip from my /29 ipv4
allocation. The router blocks ipv6 completely.

will Merlin allow the mesh thing?

I'd like to prioritise traffic in the following order:
first priority voip [ideally, reserved bandwidth]
2nd priority streaming
3rd priority everything else

Will Merlin (or Merlin+addons) allow this, too? On this old hardware?

Various QoS methods are available on that model of router:

You have to use Traditional QoS then with manual settings. Available in both stock Asuswrt and Asuswrt-Merlin.
ahhh I didn't realise.

There seems no way at first glance of giving voip the very highest priority/guaranteed bandwidth, but Ive not searched
very deeply on here or elsewhere yet. It needs like 100% priority and say 2% of the bandwidth to be guaranteed.
I thought it'd be a specific packet type. voip isn't available on the drop-down:


  • asus1.png
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I guess Merlin still allows the mesh thing? as it's closed source.
BTW I guess this website doesn't like long filenames? I had to rename the above attachment because it stuck at 0%.
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I thought it'd be a specific packet type. voip isn't available on the drop-down

You have to set it manually by port range or prioritize specific device. Traditional QoS settings are limited.

I guess Merlin still allows the mesh thing?

Yes, AiMesh is available in Asuswrt-Merlin. You don't need Asuswrt-Merlin on a node though. It may run stock Asuswrt.
Traditional QoS with AC68U will limit internet speed below 170Mbit. Adaptive QoS not working as good as I would like to - I had situations with torrents etc that was not helping much

I am using FlexQoS from amtm
What speed is the asus good up to? I'll limit the bandwidth it can use if need be on either the asus itself or the external LAN it connects to via its WAN interface.
If you insist on NAT acceleration incompatible options like Traditional QoS high-end models can do about 500Mbps. Home routers are power efficiency optimized and rely heavily on NAT acceleration techniques. For Gigabit packet processing through CPU you need x86 appliance. Home router will work for you, but you have to make sure the options you select don't impact the performance. Home routers are with "up to" specs, not guaranteed. Plus a lot of non-existing advantages type of marketing on top.
You can actually still use your existing routers after the ISP upgrade. RT-AC68U can do Gigabit wired in light configuration with no TrendMicro involvement and NAT acceleration enabled. You have to wire your second router though to get the performance there. On wireless you can get up to 500Mbps to common 2-stream AC client. Wireless AiMesh will cut the speed town under 200Mbps to node connected wireless clients.

Not sure this extra router is needed. Use the ISP provided equipment instead. If your Asus router can't do Gigabit on PPPoE - the ISP equipment can do the WAN connection, your routers will deal with your LAN behind it. With some more careful planning you can still use what you already have with acceptable performance and at no extra cost. Upgrade everything is an easy advice, but your wallet will be involved in the process.
The extra router replaces [1] the ISP router. I didn't explain clearly, sorry.
That's what I mean by "for the pppoe"

The connection is fibre. It goes like this, with regard to the asus router:

ONT/fibre => ethernet ==> pppoe router ===> 1GB switch [external LAN] ===> asus ac68u ===> internal LAN

edit: i have a /29 ipv4 and a /48 ipv6 and the asus can't handle routed ipv4

[1] it's being replaced because I don't like how my ISP have configured their router with regard to TRS-069.
I'd feel differently if they wrapped access to the port to their own helpdesk/equipment, but they don't.
It can't handle routing with NAT acceleration disabled, but with Gigabit ISP you don't need this QoS anymore. It's holding it back at the moment. After the ISP upgrade just try without this extra MikroTik router and see what happens. If all good - you save $100, some power, space, wires, and avoid the resulting double NAT situation.
It can't handle routing with NAT acceleration disabled,

not sure what you mean by "routing" here

do you mean the asus can issue a /29 real ipv4 subnet as well as ipv6 /48 and also nat?

I thought it couldn't - which is why there's (presently) an edgerouter lite 3 [1] (with nat and firewalling turned off) there to make the pppoe connection. The edgerouter will be replaced by the mikrotik.

All the asus is there for is to block anything originating externally going inbound to the internal LAN, and it uses one external ipv4. The rest of the routable [2] ipv4 /29 go to other machines directly connected via the external LAN switch with their own firewalls.

The QoS is really just for the voip. I want to make sure everything not-voip doesn't saturate the link [internal LAN ==> LAN interface] on the asus and cause call problems.

[1] this replaced the original ISP provided router.
[2] by "routable" I mean accessible from the internet.

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