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Fesiitis
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Topic Author
Posts: 45
Joined: Tue Sep 13, 2016 10:24 am
Location: Latvia, Riga

cAP ac 5 GHz upload speed is much slower than download speed

Sat Apr 16, 2022 5:38 pm

Hi,

I have been using cAP ac for several years now. And since day one I have noticed that the 5 GHz upload speed is much slower than the download speed. I don't use 2.4 GHz at all so I haven't tested the difference between upload and download speeds with 2.4 GHz. And I use cAP ac only as 5 GHz wireless router, the ether2 port is disabled.

Below you can see the difference between download and upload speeds using 5 GHz. And to be absolutely clear, the ISP provides the same upload and download speeds, i.e. if I connect the computer directly to the WAN cable, the upload speed is almost identical to the download speed.
speedtestresult.PNG
Although it does not bother me much, I would like to understand why such a problem exists at all. I have reset the router to default settings several times over time, I have always used the latest version of the RouterOS, but it has never been clear to me whether this is the problem with RouterOS itself or configuration settings, or maybe my router has some hardware problems.

The router is currently running RouterOS v7.2.1 with this configuration, which is basically the default configuration -
/interface bridge
add admin-mac=XX:XX:XX:XX:XX:XX auto-mac=no comment=defconf name=bridge
/interface ethernet
set [ find default-name=ether1 ] mac-address=XX:XX:XX:XX:XX:XX
set [ find default-name=ether2 ] disabled=yes
/interface wireless
set [ find default-name=wlan1 ] band=2ghz-onlyn country=latvia distance=\
    indoors frequency=2437 installation=indoor mode=ap-bridge radio-name=wlan1 \
    ssid="wlan1" wireless-protocol=802.11 wmm-support=enabled \
    wps-mode=disabled
set [ find default-name=wlan2 ] band=5ghz-n/ac channel-width=20/40/80mhz-XXXX \
    country=latvia disabled=no distance=indoors frequency=5220 installation=\
    indoor mode=ap-bridge radio-name=wlan2 ssid="wlan2" \
    wireless-protocol=802.11 wmm-support=enabled wps-mode=disabled
/interface list
add comment=defconf name=WAN
add comment=defconf name=LAN
/interface wireless security-profiles
set [ find default=yes ] authentication-types=wpa2-psk disable-pmkid=yes \
    eap-methods="" group-key-update=1h mode=dynamic-keys supplicant-identity=\
    MikroTik
/ip pool
add name=dhcp ranges=10.7.7.2-10.7.7.16
/ip dhcp-server
add address-pool=dhcp interface=bridge lease-time=2d name=defconf
/interface bridge port
add bridge=bridge comment=defconf interface=ether2
add bridge=bridge comment=defconf interface=wlan1
add bridge=bridge comment=defconf interface=wlan2
/ip neighbor discovery-settings
set discover-interface-list=LAN
/interface list member
add comment=defconf interface=bridge list=LAN
add comment=defconf interface=ether1 list=WAN
/ip address
add address=10.7.7.1/24 comment=defconf interface=bridge network=10.7.7.0
add address=XX.XX.XX.XX/24 interface=ether1 network=XX.XX.XX.0
/ip dhcp-client
add comment=defconf disabled=yes interface=ether1
/ip dhcp-server network
add address=10.7.7.0/24 comment=defconf gateway=10.7.7.1 netmask=24
/ip dns
set servers=91.198.156.20,194.8.2.2
/ip firewall filter
add action=accept chain=input comment=\
    "defconf: accept established,related,untracked" connection-state=\
    established,related,untracked
add action=drop chain=input comment="defconf: drop invalid" connection-state=\
    invalid
add action=drop chain=input comment="defconf: drop all not coming from LAN" \
    in-interface-list=!LAN
add action=accept chain=forward comment="defconf: accept in ipsec policy" \
    ipsec-policy=in,ipsec
add action=accept chain=forward comment="defconf: accept out ipsec policy" \
    ipsec-policy=out,ipsec
add action=fasttrack-connection chain=forward comment="defconf: fasttrack" \
    connection-state=established,related hw-offload=yes
add action=accept chain=forward comment=\
    "defconf: accept established,related, untracked" connection-state=\
    established,related,untracked
add action=drop chain=forward comment="defconf: drop invalid" \
    connection-state=invalid
add action=drop chain=forward comment=\
    "defconf: drop all from WAN not DSTNATed" connection-nat-state=!dstnat \
    connection-state=new in-interface-list=WAN
/ip firewall nat
add action=masquerade chain=srcnat comment="defconf: masquerade" \
    ipsec-policy=out,none out-interface-list=WAN
/ip service
set telnet disabled=yes
set ftp disabled=yes
set www address=10.7.7.0/24
set ssh disabled=yes
set api disabled=yes
set winbox address=10.7.7.0/24
set api-ssl disabled=yes
/ipv6 firewall address-list
add address=::/128 comment="defconf: unspecified address" list=bad_ipv6
add address=::1/128 comment="defconf: lo" list=bad_ipv6
add address=fec0::/10 comment="defconf: site-local" list=bad_ipv6
add address=::ffff:0.0.0.0/96 comment="defconf: ipv4-mapped" list=bad_ipv6
add address=::/96 comment="defconf: ipv4 compat" list=bad_ipv6
add address=100::/64 comment="defconf: discard only " list=bad_ipv6
add address=2001:db8::/32 comment="defconf: documentation" list=bad_ipv6
add address=2001:10::/28 comment="defconf: ORCHID" list=bad_ipv6
add address=3ffe::/16 comment="defconf: 6bone" list=bad_ipv6
/ipv6 firewall filter
add action=accept chain=input comment=\
    "defconf: accept established,related,untracked" connection-state=\
    established,related,untracked
add action=drop chain=input comment="defconf: drop invalid" connection-state=\
    invalid
add action=accept chain=input comment="defconf: accept ICMPv6" protocol=\
    icmpv6
add action=accept chain=input comment="defconf: accept UDP traceroute" port=\
    33434-33534 protocol=udp
add action=accept chain=input comment=\
    "defconf: accept DHCPv6-Client prefix delegation." dst-port=546 protocol=\
    udp src-address=fe80::/10
add action=accept chain=input comment="defconf: accept IKE" dst-port=500,4500 \
    protocol=udp
add action=accept chain=input comment="defconf: accept ipsec AH" protocol=\
    ipsec-ah
add action=accept chain=input comment="defconf: accept ipsec ESP" protocol=\
    ipsec-esp
add action=accept chain=input comment=\
    "defconf: accept all that matches ipsec policy" ipsec-policy=in,ipsec
add action=drop chain=input comment=\
    "defconf: drop everything else not coming from LAN" in-interface-list=\
    !LAN
add action=accept chain=forward comment=\
    "defconf: accept established,related,untracked" connection-state=\
    established,related,untracked
add action=drop chain=forward comment="defconf: drop invalid" \
    connection-state=invalid
add action=drop chain=forward comment=\
    "defconf: drop packets with bad src ipv6" src-address-list=bad_ipv6
add action=drop chain=forward comment=\
    "defconf: drop packets with bad dst ipv6" dst-address-list=bad_ipv6
add action=drop chain=forward comment="defconf: rfc4890 drop hop-limit=1" \
    hop-limit=equal:1 protocol=icmpv6
add action=accept chain=forward comment="defconf: accept ICMPv6" protocol=\
    icmpv6
add action=accept chain=forward comment="defconf: accept HIP" protocol=139
add action=accept chain=forward comment="defconf: accept IKE" dst-port=\
    500,4500 protocol=udp
add action=accept chain=forward comment="defconf: accept ipsec AH" protocol=\
    ipsec-ah
add action=accept chain=forward comment="defconf: accept ipsec ESP" protocol=\
    ipsec-esp
add action=accept chain=forward comment=\
    "defconf: accept all that matches ipsec policy" ipsec-policy=in,ipsec
add action=drop chain=forward comment=\
    "defconf: drop everything else not coming from LAN" in-interface-list=\
    !LAN
/system clock
set time-zone-name=Europe/Riga
/system identity
set name=Router
/system routerboard mode-button
set enabled=yes on-event=dark-mode
/system script
add comment=defconf dont-require-permissions=no name=dark-mode owner=*sys \
    policy=ftp,reboot,read,write,policy,test,password,sniff,sensitive,romon \
    source="\r\
    \n   :if ([system leds settings get all-leds-off] = \"never\") do={\r\
    \n     /system leds settings set all-leds-off=immediate \r\
    \n   } else={\r\
    \n     /system leds settings set all-leds-off=never \r\
    \n   }\r\
    \n "
/tool bandwidth-server
set enabled=no
/tool mac-server
set allowed-interface-list=LAN
/tool mac-server mac-winbox
set allowed-interface-list=LAN
/tool mac-server ping
set enabled=no

Does anyone have any ideas that I could change in configuration to improve 5 GHz upload speed?

Thanks!
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erlinden
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Posts: 1920
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Location: Netherlands

Re: cAP ac 5 GHz upload speed is much slower than download speed

Sat Apr 16, 2022 6:26 pm

Can you please share the connection speed (wireless, registration, tx/rx rate)?
And what is the speed when testing wired?
 
Fesiitis
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Topic Author
Posts: 45
Joined: Tue Sep 13, 2016 10:24 am
Location: Latvia, Riga

Re: cAP ac 5 GHz upload speed is much slower than download speed

Wed May 04, 2022 3:12 pm

Sorry for the late reply. Here are three results:

When downloading
whendownloading.PNG
When uploading
whenuploading.PNG
When idle
whenidle.PNG

At the moment, I don't have a long enough RJ45 cable in my home to connect my router to my desktop so that I can test the speed with a cable. However, the last time I ran the test, the upload speed was the same as the download speed.
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holvoetn
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Location: Belgium

Re: cAP ac 5 GHz upload speed is much slower than download speed

Wed May 04, 2022 3:22 pm

Couldn't you make those screenshots a bit wider ??
:?

And what's the real measured speed when connected to that access point ?
Same as in first post ?
 
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bpwl
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Re: cAP ac 5 GHz upload speed is much slower than download speed

Wed May 04, 2022 10:36 pm

Well most of the wifi information is there in the "registration" screenshots.
Signal is OK, Signal to Noise is OK, CCQ is OK.

The interface rate varies over time, but lets take the first screenshot
Klembord-2.jpg
No major reason to expect low performance from the upload (Rx rate) , compared with the download (Tx).
It is not "perfect" , as that should have been "866Mbps-80MHz/2S/SGI". So there are some missed transmissions, that make the devices downgrade the MCS.
Download is MCS07, while upload is MCS05 (but these values do vary over time and are load dependent.)
To find out where this comes from, the first hint is in the Frames/HW Frames ratio. HW Frames are the # of frames transmitted , Frames the # that made it succesfully.
Should be fairly good with the high CCQ.

(better screenshot with "detail mode" ? Or just some columns can be hidden)

But this will not explain why the upload is so much slower, it could account for some reduction but not 4 times lower.
Any missed transmission (retransmission) can trigger "TCP congestion avoidance" algoritmes, that could reset the TCP speed used by the clients.
This can reduce the average throughput considerably! Speedtest.net is using TCP for it's tests.
"TCP congestion control" depends on the clients software/drivers: https://en.wikipedia.org/wiki/TCP_congestion_control .
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Ca6ko
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Location: Kharkiv, Ukraine

Re: cAP ac 5 GHz upload speed is much slower than download speed

Thu May 05, 2022 12:00 am

Try setting the Guard interval - long
 
Fesiitis
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Posts: 45
Joined: Tue Sep 13, 2016 10:24 am
Location: Latvia, Riga

Re: cAP ac 5 GHz upload speed is much slower than download speed

Sat May 07, 2022 4:33 pm

Ca6ko, unfortunately does not help, the same results as in the first post.

bpwl, thanks for the detailed explanation. Here is a picture showing the HW Frames and Frames columns, looks like Tx HW Frames and Tx Frames are quite different after three speedtest attempts.
frames.PNG
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bpwl
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Re: cAP ac 5 GHz upload speed is much slower than download speed

Sat May 07, 2022 6:40 pm

Most information is there, not all with MT (eg AMPDU and AMSDU aggregation?) , and interpretation is not at all easy.
I have no clue on what triggered your slow upload.

The rest is just all speculation.

The extra data learns that in TX some 11% did not arrive at the first attempt, for whatever reason. Not too bad, as the standard MT hardware retransmit is 7 times by default.
The 97% CCQ learns that it quite often succeeds within the 7 attempts.

The RX is even cleaner, with almost 100% first transmit success, but only one stream is used now. The interface rate is also the max rate possible for one stream (433Mbps)

MT is not giving aggregation numbers, but if the packet/frame ratio could be used as indicator, it would mean that only the TX is using A-MSDU and/or A-MPDU aggregation.
Maybe the number of TX and RX bytes then learns about the packet size.
Not using A-MSDU or A-MPDU aggregation would limit the net throughput! With a 433Mbps data rate, and a 1500byte transfer size , the max net data rate is 44,2Mbps when a 6 Mbps base-rate is used. (https://gjermundraaen.com/thewifiairtimecalculator/).
But MT is not giving us this information, so it it a lot of speculation and guessing, and the average ratio's are not the ones for the transmission itself.
 
Fesiitis
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Posts: 45
Joined: Tue Sep 13, 2016 10:24 am
Location: Latvia, Riga

Re: cAP ac 5 GHz upload speed is much slower than download speed

Thu Aug 25, 2022 2:10 am

Just to let you know, if anyone else has had a similar situation, I discovered the cause of the problem quite by accident, it's the "fasttrack-connection" firewall rule. After I disabled this rule, the 5GHz upload speed "skyrocketed". Even if I disable the "fasttrack-connection" rule at the moment when the upload test has just started, it starts to increase significantly.

FastTrack enabled.
fasttrackenabled.PNG
FastTrack disabled.
fasttrackdisabled.PNG
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carl0s
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Re: cAP ac 5 GHz upload speed is much slower than download speed

Thu Aug 25, 2022 1:44 pm

Just to let you know, if anyone else has had a similar situation, I discovered the cause of the problem quite by accident, it's the "fasttrack-connection" firewall rule. After I disabled this rule, the 5GHz upload speed "skyrocketed". Even if I disable the "fasttrack-connection" rule at the moment when the upload test has just started, it starts to increase significantly.

FastTrack enabled.
fasttrackenabled.PNG

FastTrack disabled.
fasttrackdisabled.PNG
Thank you for sharing. I'll keep this in mind next time I am working on something similar.
 
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bpwl
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Re: cAP ac 5 GHz upload speed is much slower than download speed

Thu Aug 25, 2022 4:45 pm

So disabling this, to get full speed upload, even without reboot. ???
add action=fasttrack-connection chain=forward comment="defconf: fasttrack" \
    connection-state=established,related hw-offload=yes
Interesting. Can anyone explain? (Things like, "not all packets are fasttracked, and the same regular rule is needed" ... ???????)

Fasttrack is supposed to be faster. Just wonder: Do some packets get dropped or mis-directed? ROS7.2.1 specific behavior? hw-offload related?

https://wiki.mikrotik.com/wiki/Manual:IP/Fasttrack
 
Fesiitis
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Location: Latvia, Riga

Re: cAP ac 5 GHz upload speed is much slower than download speed

Fri Aug 26, 2022 6:40 pm

So disabling this, to get full speed upload, even without reboot. ???
Yes, I watched one video about the "FastTrack" rule that also explained the cases when it is better to disable it. So, out of interest, I disabled it and ran a speed test without restarting router.

And it looks like this rule only affects the wlan2 (and maybe wlan1 too) adapter. A couple of months ago I did a test by connecting a computer with a network cable to the ether2 port. The upload speed was exactly what it should be. At that time, the FastTrack rule was on.

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