WIFI only at 400Mbps Sophos AP55

Usbkey said:

Dear all

I just bought a AP55 and according to sophos its radio type is 802.11ac

But my MacBook Pro and Google Pixel can only connect at 400Mbps speed.

Both my MBP and Google Pixel supports 802.11ac, when MBP connects to AP55 connection details shows AP PHY type is 802.11ac but I just don't understand why only 400Mbps

any idea?

thanks

USBKey,

I am not sure how you are determining this 400Mbps number.  Is this the overall wireless connection speed between device and AP, or is it a measure of throughout to an internal network or external internet source (though the AP-wireless/wired network and Sophos/security devices)?

This issue depends on several things:

1. On the Wi-Fi side of the issue, The MacBook Pro is a 3x3 device.  The AP55 is only 2x2.  This means the AP55 can only provide 2/3 of the maximum Wi-Fi capability of the MBP.  This may only be part of the issue.

The other side of the issue may be your Sophos device or whatever firewall/security device you use (if you're using Sophos Cloud Wi-Fi).  There are two possible problems here:

2. The main issue is that your Sophos SG UTM or XG Firewall (or other firewall/security device) may not be sized properly to be able to handle all of your network traffic and connections at maximum speeds and throughputs.  Each model has certain physical speed/throughput limitations.

3. The other issue is that each Sophos UTM/Firewall model also has certain software limitations as well.  Certain features, when activated in the SG UTM and SG Firewall, slows down the traffic flowing through it.  If you are using Cloud Wi-Fi, then the firewall you are going through is slowing down certain traffic as it tries to scan the traffic while en route.

Depending on your particular setup, settings, and testing, you may get different results regardless of top theoretical speeds possible.  For example:

I am currently on a system that has a an Apple Time Capsule (tower) in bridge mode connected to an SG Firewall.  The Time Capsule AP and the MBP are both are 3x3 AC, so the Wi-Fi connects to my MBP at full 1.3Gbps.  When I test using an internet based test that goes through the AP, the network, and the Firewall to the internet, I only get a maximum of 350Mbps.  That's because the internet service here is 350Mbps.

I can get even slower results:

When When I activate Scanning FTP for malware in the SG Firewall, the Ookla Speedtest app on my MBP is limited to 100Mbps while the Ookla website http://beta.speedtest.net measures the full 350Mbps internet service here.  This is because the because the macOS App uses FTP while the website is using a different file transfer protocol that bypasses my FTP scanning.

*The Time Capsule AP provides a combined 20Mhz/40Mhz/80Mhz side signal, but most apple devices only us 40Mhz.  Setting your Wi-Fi to 40Mhz may also help with some Apple Wi-Fi issues.

Hi David

Thanks very much for your time and reply.

400Mbps is the connection speed between my phone/tablets/laptop to my AP55.

I am running sophos XG on a Dell Optiplex i5 3570 SFF PC with 8G RAM, definitely not a sizing issue here.

I noticed a reply made by Sophos engineer in another post 

The  Max connection speed on AP100 with 80Mhz channel width is 1.3Gbps. Please note that the client has to be a 3 spatial stream 802.11AC device to achieve this Data rate.

Max connection speed on AP55 with 80Mhz channel width is 866Mbps.  The default channel width is set to 40Mhz to suite enterprise deployments.

You can change the default Channel width from CLI.

and here is how to check what channel is allowed on AP55

6. Which Wireless Channels are currently allowed on this AccessPoint?

root@OpenWrt:/# cat /tmp/ap_caps

allowed_channels=1,2,3,4,5,6,7,8,9,10,11,12,13,36,40,44,48,52,56,60,64,100,104,108,112,116,132,136,140

I haven't tried this yet as I need to get a usb-console cable. Currently I am happy with my XG and two AP55s

Thanks

You're welcome.

The traffic shaping and scanning settings in your XG Firewall can constrict data throughput through it regardless of how fast your Firewall Appliance runs.  Since the 400Mbps measurement was taken between your AP and the devices, then the firewall appliance is probably not the issue, but the AP settings may be.

The Sophos Tech is saying the same things as I did in my first point - about the max 2x2 spatial stream of your AP55 versus the 3x3 capability of the MBP.  There are other issues I didn't address earlier like interference, but since you're using AC you're using the best interference mitigating capabilities of your AP.  

Moving your devices around and re-testing might help.  Checking to see how your Wi-Fi works in conjunction to other Wi-Fi around you may also help.   In the App Store for macOS, you can download WiFi Explorer or WiFi Scanner to get a look at the Wi-Fi signals at your location.  Both apps are very similar, and they will display how your Wi-Fi is broadcasting compared to other Wi-Fi systems around you.  These apps will tell you if your AP is using 20Mhz, 40Mhz, or 80Mhz channel width and at what bandwidth.

Have you tried resetting your AP?  How about updating the AP firmware? Go to System > Backup & Firmware > Pattern Updates.  Click "Update Pattern Now"

Have you checked the Firmware of your XG Firewall too?  Have you also checked to see which Firmware your XG Firewall is running?  System > Backup & Firmware > Firmware

Hi David

Yes I am running both latest XG and AP firmware, I apply updates whenever they are available.

I believe this is related to the channel settings and will try to modify it during weekend, just got my console cable today.

will let you know

Thanks

Hi David

Yes I am running both latest XG and AP firmware, I apply updates whenever they are available.

I believe this is related to the channel settings and will try to modify it during weekend, just got my console cable today.

will let you know

Thanks