Asus Zenwifi AX XT8 - Dual WAN Setup

I got two single units of Asus Zenwifi AX XT8 last month to get better range since its a mesh setup and can have better speeds with 3 of my devices with WiFi 6 support.

After I got them, set them up and using them for a while. In the Web interface there is a Dual WAN option also with two sub options failover and load balancing. Wondering what they were and started to search the net and got some info. My Airtel Xstream fiber Huawei ONT is in bridge mode. To check the speeds of this new AX setup, I opted for plan change from Airtel Thanks app initially fot 300 Mbps(used for few days) and later for 1gbps plan(used for a day) . The plan change couldn't happen initially. Assuming its due to bridge mode, I reverted Huawei to router mode and plan change was done. But my setup was under double NAT.

One day my existing Airtel Xstream fiber connection(200 Mbps plan) was disrupted and due to kids online classes and other wfh issues, thought of taking a backup Internet connection and saw that Jio is offering a one month trial. Hence applied and got it installed in 4 days. I want to set this Jio with 399 base plan and use it as a backup only after the initial trial period in which the speed is upto 150 Mbps. This was my initial plan. After I got the Jio installed, I immediately switched off the wifi from Jio router. Couldn't use it in bridge mode as it can't be done as of now. So, basically both the Airtel and Jio were setup in such a way that both are in double NAT.

I tried load balancing option under Dual WAN setup with Airtel as Primary Wan and Jio as secondary with a lan port acting as wan input for Jio. Airtel is at 200Mbps speed and Jio at 150 Mbps speed.

I thought the ratio column is to split the no of packets between both connections based on the ratio and nothing linked to speed. Hope my understanding is correct. Pl correct if I'm not.

I got speeds of 350 Mbps But off late I've found that it is looking for net connectivity in between as the WhatsApp icon appears in notification bar saying checking for messages. This appears for a second only. Also kids reported that they got an unstable internet message while using zoom app for classes.

Is my load balancing setup wrong as the speeds of both are different and the ratio I gave is not 1:1. I tried 4:3, 2:1 options. Is the slight delay due to transitioning from Airtel to jio or vice versa. I initially thought that it's due double NAT with both Airtel and Jio and converted Huawei back to bridge mode. Now, Asus router is under double NAT with Jio only.

Also, I couldn't open some Jio pages from app or via browser. So, I entered 8.8.8.8 in the dns column under dhcp in the router.

I removed the load balancing setup and now set it up as fail over only to invoke Jio only when Airtel fails.

Pl let me know if my load balancing setup is wrong or can I tweet the load balancing setup for better performance. If it works, after the Jio trial period is over, I'll put both Airtel and Jio with 100Mbps plan each to attain 200 Mbps. Just an option. If not only fail over option is left.

Sorry for the long post.

Thanks in advance.

First of all, I must say that I am not familiar with the Asus device specific configuration. However, generally, for load balancing, there are different ways it can be done, however the Asus device might abstract that or show only limited options.

The load balance option might be doing it on a per connection basis, so for each new connection, depending on the ratio and load, it would chose WAN 1 or 2. Most applications make multiple connections and it is possible that the connections take different path (some of them through WAN 1 and some of them through WAN 2) which might be leading to some instability especially for video calls and things like that.

Another option is to load balance based on source IP address, so if you have multiple client devices, each client would consistently go out via a specific WAN. I have felt that such a configuration is more stable. I am not sure if Asus let's you do something like this though. So when you have more client devices, both your WAN connections are utilised, balancing the load. A per connection based config however would let you use the combined bandwidth on the same client device (when doing multi threaded speed tests or downloads etc)

Based on [WAN] Dual WAN introduction and setup | Official Support | ASUS India, it seems like it's very basic load balancing config.

Other routers running custom firmware gives you more freedom to tweak the config as you require, but stock firmware may not let you do that.

Dear @varkey Thank you very much for the info on load balance. After your post, I checked the Web interface of Asus Zenwifi AX XT8 dual wan setup and under load balancing option, there is an option of routing rules by which one can setup a device (ip address) to access a particular wan/connection.

In this, I entered two ip addresses of two laptops to access the 2nd wan (Jio connection) along with my mobile to access 1st wan (Airtel) and they are working fine after that. When I do a speed test on these laptops, it's showing speed as per the Jio plan of 150 Mbps (around 140 Mbps) . Similarly the speedtest on my mobile was showing speeds in the range of 200 to 230 Mbps as per Airtel plan.
There were no issues reported as of now.

I didn't add other devices to the rules section. When there were no devices added to the rules section , it showed speeds of upto 350 Mbps (200+150) with few slight delays in between. But when rules were set up to access specific wan connection, the devices were reporting as per the plan connection.

Yeah, looks like it's a per connection load balancing like I thought. In my OpenWRT router for example, I can enable stickiness, so basically any device would stick to one WAN connection until the sticky timeout.

I've not enabled it as I don't do load balancing, just failover. My backup WAN is over LTE/4G so load balancing won't be ideal.

Also, in your case, unless all the devices combined need more throughput than Airtel's plan speed, perhaps its better to just leave Jio as backup ie failover on the 399 plan.

@varkey Whats the per connection load balancing type. Isn't it the same one that I setup using the routing rules. I was of the opinion that the rule is valid for the device until its removed from the rule table. So, the device will use the same WAN connection until Its removed.

Is there a chance the rule fails when the laptop is started again tomorrow when a different IP is assigned to it by router and the rule fails as I've input the IP address or is it interlinked with mac address of the device. If so, I need to link the same lan IP for that device in the IP binding section.