RT-AC86U - Slow Guest WiFi

[Asuswhyslowshy]

Hi all

I have a guest SSID set up on my router to use with things that I don’t want having intranet access; smart devices etc, workplace devices.

I noticed today my speed was like 0.5Mbps down on this guest network. My ISP speed is 500Mbps and I’ll get this without fault on my normal SSID, but my guest network seem to waver between 0.5 and 90Mbps, usually around 20 with the upload being faster!

Firmware is up to date and no bandwidth limit is set. Has anyone else experienced this, or am I missing a setting somewhere? I’d like full speeds really. Router is trouble free otherwise. Slower speeds witnessed on multiple devices, nearby main SSID devices at full speed!

 

[degrub]

Which band is the Guest network on ?
What is the link rate displayed in the Windows wireless connection status page when you are linked to the Guest network SSID and then same data from the "regular" wifi SSID.
What band(s) is the regular wifi network connection on ?

 

[bennor]

Firmware is up to date...

For clarity, please list specific firmware version.

 

[Asuswhyslowshy]

Which band is the Guest network on ?
What is the link rate displayed in the Windows wireless connection status page when you are linked to the Guest network SSID and then same data from the "regular" wifi SSID.
What band(s) is the regular wifi network connection on ?

2.4ghz,

For clarity, please list specific firmware version.

3.0.0.4.386_51967

 

[Asuswhyslowshy]

Which band is the Guest network on ?
What is the link rate displayed in the Windows wireless connection status page when you are linked to the Guest network SSID and then same data from the "regular" wifi SSID.
What band(s) is the regular wifi network connection on ?

Regular network is 5ghz usually but also uses 2.4

Link rate 144/144 WiFi 4 on guest
866/866 WiFi 5 on normal

 

[Asuswhyslowshy]

 

[degrub]

Regular network is 5ghz usually but also uses 2.4

Link rate 144/144 WiFi 4 on guest
866/866 WiFi 5 on normal

What are the channel widths for both guest and normal ?

 

[wouterv]

The basic WiFi settings for regular access and Guest access are equal.
The difference is what you can make different in the "Guest" settings, these are: SSID, Wireless Security (like WPA), access time and allow or disallow Internet access.
The same wireless client device connected regular or connected as Guest to the same frequency band (5 GHz or 2.4 GHz) shall perform the same, this is the first thing to confirm.
Different wireless client devices on different frequency bands will for quite sure have different speeds.
5 GHz is expected to give the highest speed, but a shorter distance range compared to 2.4 GHz.
Important is to check the channel band width setting on both frequency bands: unless you live in a rural area it is recommended to set 2.4 GHz to a fixed channel bandwidth of 20 MHz to avoid neighbor disturbance, this limits disturbance but also lowers the speed.
The 5 GHz band shall be left on Auto for the channel bandwidth.
The RT-AC86U is as said a Wi-Fi 5 class router, it also allows Wi-Fi 4 and older connections, a higher class can give higher speeds, the supported class in general depends on the age of the wireless client device.
Distance between the router and the wireless client device also determines the final speed: the longer the distance, the more the speed gets degraded.
The final crucial specification for speed is the number of data streams: the RT-AC86U router supports 3 streams on 2.4 GHz and 4 streams on 5 GHz. More data streams means a higher speed. Far most wireless client devices do only support 1 data stream, some do support 2 or more data streams.

The router Advanced Settings > System Log > Wireless Log page shall give some clue, look for the Stations List with connected devices and check the TX rate and RX rate for both frequency bands:

In the above you see the numbers of two wireless client devices with different specifications connected to the router and having different rates.

First confirm as stated above in bold.
Also make screen shots of the TX rate and RX rate as found in the Stations List for both frequency bands.

 

[Tech9]

Link rate 144/144 WiFi 4 on guest
866/866 WiFi 5 on normal

Both are 2-stream clients. Up to ~90Mbps is all you can get on 2.4GHz band (20MHz channel bandwidth, 802.11n) and up to ~550Mbps on 5GHz band (80MHz wide channel bandwidth, 802.11ac) and only in case your Wi-Fi environment is relatively quiet and the client connected has RSSI of -54dBm or better. Lower 2.4GHz speed ~20Mbps is expected and normal with busy 2.4GHz band.

 

[Asuswhyslowshy]

Both are 2-stream clients. Up to ~90Mbps is all you can get on 2.4GHz band (20MHz channel bandwidth, 802.11n) and up to ~550Mbps on 5GHz band (80MHz wide channel bandwidth, 802.11ac) and only in case your Wi-Fi environment is relatively quiet and the client connected has RSSI of -54dBm or better. Lower 2.4GHz speed ~20Mbps is expected and normal with busy 2.4GHz band.

Thanks. I thought 2.4ghz supported higher. The environment is quite quiet. The thing that’s bothering me most is the fluctuation in speed, sometimes next to nothing, sometimes acceptably fast, 90 or so.

I’m actually in quite a quiet wifi environment - only around 5-6 other SSIDs that aren’t mine in range and they’re all quite weak!

 

[Asuswhyslowshy]

What are the channel widths for both guest and normal ?

I don’t think I can see the width for guest alone. 2.4ghz is set to 20-40 and 5ghz is set to 20/40/80

 

[Asuswhyslowshy]

The basic WiFi settings for regular access and Guest access are equal.
The difference is what you can make different in the "Guest" settings, these are: SSID, Wireless Security (like WPA), access time and allow or disallow Internet access.
The same wireless client device connected regular or connected as Guest to the same frequency band (5 GHz or 2.4 GHz) shall perform the same, this is the first thing to confirm.
Different wireless client devices on different frequency bands will for quite sure have different speeds.
5 GHz is expected to give the highest speed, but a shorter distance range compared to 2.4 GHz.
Important is to check the channel band width setting on both frequency bands: unless you live in a rural area it is recommended to set 2.4 GHz to a fixed channel bandwidth of 20 MHz to avoid neighbor disturbance, this limits disturbance but also lowers the speed.
The 5 GHz band shall be left on Auto for the channel bandwidth.
The RT-AC86U is as said a Wi-Fi 5 class router, it also allows Wi-Fi 4 and older connections, a higher class can give higher speeds, the supported class in general depends on the age of the wireless client device.
Distance between the router and the wireless client device also determines the final speed: the longer the distance, the more the speed gets degraded.
The final crucial specification for speed is the number of data streams: the RT-AC86U router supports 3 streams on 2.4 GHz and 4 streams on 5 GHz. More data streams means a higher speed. Far most wireless client devices do only support 1 data stream, some do support 2 or more data streams.

The router Advanced Settings > System Log > Wireless Log page shall give some clue, look for the Stations List with connected devices and check the TX rate and RX rate for both frequency bands:
View attachment 66443
In the above you see the numbers of two wireless client devices with different specifications connected to the router and having different rates.

First confirm as stated above in bold.
Also make screen shots of the TX rate and RX rate as found in the Stations List for both frequency bands.

My iPad Pro 12.9 2nd gen on 5ghz - 495 down 450 up. On 2.4ghz - 75 down 80 up. I did this via wireless Mac filtering, rejecting my iPad MAC from 5ghz

So it seems the issue is 2.4ghz rather than the guest network itself..!

 

[Tech9]

I thought 2.4ghz supported higher.

Only if the router is AX/BE-class, it's enabled on 2.4GHz band and to compatible AX/BE client.

You can see 300Mbps, 600Mbps, 750Mbps even 1000Mbps marketing numbers on AC-class routers for link speeds on 2.4GHz band, but they are not practically usable due to number of limitations (40MHz wide channel, 4-stream client, non-standard QAM).