Capsman performance degradation due to many clients?

RouterOS Wireless Networking
1

Hi all!
For a customer I have set up Capsman using ROS 6.49.7, RBM33G as controller and 3x cAP ac as caps, 2.4 and 5 GHz (40 Mhz), clear channel. Local forwarding.
He is hooking up approx 40 pcs Chromebooks at a time to do some updates/SSD erasing and complains that in between wireless is slow, for instance loading a website or downloading a script, even when bandwidth usage is low.
This setup replaces a previous installation based on Ubiquiti, reported to be running smoothly all the way…

Capsman controller CPU is low, connection is 200Mbps fiber so total capacity is no bottleneck.
For the time being, due to AP positions, maybe 20-30 of the Chromebooks are on the same AP, all of them support 5GHz and connects to 5GHz.
Signal is all in the -45 to -60 range, good uplink but rather moderate uplink, typical 120 Mbps or so.
Have tried to disable 5GHz but same happens when on 2.4, doing anything against the internet on any of the chromebooks keeps the connection lagging

So what can possibly be done to improve performance?
Any practical limitation on number of clients on an AP using CapsMan?

2

I don’t think there is much you can do. Ensure multicast helper and keepalive is disabled, try setting basic rates to 6+12+24 instead of 6 only. If none of this helps: Go for another vendor.

3

Can you share your config?
/export file=anynameyoulike(and remove any personal information).

4

Thank you for your tips!
Tried to explicitly disable multicast helper and keepalive now (instead of default settings), awaiting feedback from customer.
Thereafter, if no improvement is seen, I’ll try to change basic rates.

5

Thank you!
Here is my config anonymized (any comments are appreciated):

Controller:

# jan/11/2023 06:24:32 by RouterOS 6.49.7
# software id = ****-****
#
# model = RBM33G
# serial number = F0EB0*****
/caps-man channel
add band=2ghz-g/n extension-channel=disabled frequency=2412 name=channel-2412 \
    tx-power=26
add band=2ghz-g/n extension-channel=disabled frequency=2437 name=channel-2437 \
    tx-power=26
add band=2ghz-g/n extension-channel=disabled frequency=2462 name=channel-2462 \
    tx-power=26
add band=5ghz-n/ac control-channel-width=20mhz extension-channel=Ce \
    frequency=5180 name=channel-5180 tx-power=26
add band=5ghz-n/ac control-channel-width=20mhz extension-channel=Ce \
    frequency=5220 name=channel-5220 tx-power=26
add band=5ghz-n/ac control-channel-width=20mhz extension-channel=Ce \
    frequency=5260 name=channel-5260 tx-power=26
/caps-man datapath
add client-to-client-forwarding=yes local-forwarding=yes name=mydatapath
/caps-man configuration
add channel=channel-2412 country=brazil datapath=mydatapath \
    keepalive-frames=disabled multicast-helper=disabled name=\
    mycfg-2.4-2412 ssid=myssid
add channel=channel-2437 country=brazil datapath=mydatapath \
    keepalive-frames=disabled multicast-helper=disabled name=\
    mycfg-2.4-2437 ssid=myssid
add channel=channel-2462 country=brazil datapath=mydatapath \
    keepalive-frames=disabled multicast-helper=disabled name=\
    mycfg-2.4-2462 ssid=myssid
add channel=channel-5180 country=brazil datapath=mydatapath \
    keepalive-frames=disabled multicast-helper=disabled name=\
    mycfg-5-5180 ssid=myssid
add channel=channel-5220 country=brazil datapath=mydatapath \
    keepalive-frames=disabled multicast-helper=disabled name=\
    mycfg-5-5220 ssid=myssid
add channel=channel-5260 country=brazil datapath=mydatapath \
    keepalive-frames=disabled multicast-helper=disabled name=\
    mycfg-5-5260 ssid=myssid
/interface ethernet
set [ find default-name=ether1 ] comment=\
    "Connection to main router building B"
set [ find default-name=ether2 ] comment="LAN (Erasing network)"
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
/ip pool
add name=pool1 ranges=10.0.0.100-10.0.3.254
/ip dhcp-server
add address-pool=pool1 disabled=no interface=ether2 name=server1
/caps-man access-list
add action=accept disabled=no interface=all signal-range=-85..120 \
    ssid-regexp=""
add action=reject disabled=no interface=all signal-range=-120..-86 \
    ssid-regexp=""
/caps-man manager
set ca-certificate=auto certificate=auto enabled=yes upgrade-policy=\
    suggest-same-version
/caps-man provisioning
add action=create-dynamic-enabled hw-supported-modes=g identity-regexp=2412 \
    master-configuration=mycfg-2.4-2412 name-format=identity
add action=create-dynamic-enabled hw-supported-modes=g identity-regexp=2437 \
    master-configuration=mycfg-2.4-2437 name-format=identity
add action=create-dynamic-enabled hw-supported-modes=g identity-regexp=2462 \
    master-configuration=mycfg-2.4-2462 name-format=identity
add action=create-dynamic-enabled hw-supported-modes=a identity-regexp=5180 \
    master-configuration=mycfg-5-5180 name-format=identity
add action=create-dynamic-enabled hw-supported-modes=a identity-regexp=5220 \
    master-configuration=mycfg-5-5220 name-format=identity
add action=create-dynamic-enabled hw-supported-modes=a identity-regexp=5260 \
    master-configuration=mycfg-5-5260 name-format=identity
/ip neighbor discovery-settings
set discover-interface-list=!dynamic
/ip address
add address=10.0.0.1/22 interface=ether2 network=10.0.0.0
add address=192.168.9.10/24 interface=ether1 network=192.168.9.0
/ip dhcp-server network
add address=10.0.0.0/22 dns-server=10.0.0.1 gateway=10.0.0.1
/ip dns
set allow-remote-requests=yes servers=193.213.112.4,130.67.15.198
/ip firewall nat 
add action=masquerade chain=srcnat out-interface=ether1
add action=redirect chain=dstnat comment=\
    "Redirect HTTP port 80 to Proxy listening port 8081" dst-port=80 \
    in-interface=ether2 protocol=tcp to-ports=8081
/ip proxy
set cache-on-disk=yes cache-path=ProxyDisk/web-proxy enabled=yes \
    max-cache-object-size=10000000KiB max-fresh-time=1d port=8081 \
    src-address=10.0.0.1
/ip proxy cache
add disabled=yes src-address=10.0.0.0/22
/ip route
add distance=1 gateway=192.168.9.1
/snmp
set enabled=yes
/system identity
set name="my_router"
/tool graphing interface
add allow-address=193.215.16.0/29
/tool romon
set enabled=yes secrets=mysecret

Cap:

# jan/06/1970 20:41:13 by RouterOS 6.49.7
# software id = ****-****
#
# model = RBcAPGi-5acD2nD
# serial number = F9AD0******
/interface bridge
add name=bridge1 protocol-mode=none
/interface bridge port
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=ether2
/interface wireless cap
set bridge=bridge1 discovery-interfaces=bridge1 enabled=yes interfaces=\
    wlan1,wlan2
/ip address
add address=192.168.2.20/24 interface=bridge1 network=192.168.2.0
/ip dns
set allow-remote-requests=yes servers=192.168.2.1,8.8.8.8
/ip route
add distance=1 gateway=192.168.2.1
/system identity
set name="mycap-2412-5180"
/system ntp client
set server-dns-names=pool.ntp.org
/tool romon
set enabled=yes secrets=mysecret
6

Mikrotik does not release WiFi access points that can operate at this power without reducing the transmission speed.
Screenshot_4.png
The 2.4 power must be lowered relative to 5GHz for normal dual-band coverage at the same time.
Look here http://forum.mikrotik.com/t/degraded-wifi-performance/158249/1



add action=create-enabled hw-supported-modes=n
Don’t use outdated a,b.g standards, use only n/ac

This is more of a limitation of the CAP ac device itself.
From practice, the optimal load is up to 15 active clients per radio interface.

1.Show a scan of the air from each point in each band.
2 Show the registration table

7

Noted, have reduced Tx power to 20 for 2.4, making 17 dBm show at the AP.
The reason for cranking it up was that customer complained about “medium signal strength” indicated on the Chromebooks.




My intention was to use this setting in provisioning purely for separating between 2.4 and 5GHz radios, AFAIK this won’t restrict the mode with which the clients connect to the Cap?
Here I use all cAP ac and it will be qualified anyway.
Regarding the wireless NICs of the Chromebooks they are what they are, right? I see most of them connect in ac.
I have set modes to gn and ac respectively.
Pure n is not available.



Must do this tomorrow when the customer is hooking up the Crhomebooks.
BTW registration until now shows excellent rates (300-400) for uplink but shit for downlink.

8

take a look at this presentation

https://youtu.be/pmtB3LlwquA

9

Apart from placing the APs so that roughly 1/3 of the chromebooks will connect to each automatically, how can I go about to restrict the number of clients on one cap? Or maybe “move” them to another one?

10

you can influence cliente behavior on AP selection whit:

AP physical location
AP TX power
Taking advantage of environment to limit AP coverage

Last resort will be Access-lists, be ware of testing them properly to avoid degrading user experience

11

ACv1. in 2023.

No MU-MIMO.

There is an expression for this kind of lecture.