Page 1 of 1

RB2011+hAP stable, low bandwidth wifi - how to?

Posted: Wed Feb 24, 2016 5:46 pm
by lapsio
Hello. I need to use wifi for PCM audio transport in home (flat), short distance without obstacles ~3m. It seems to require stable 350kbps which doesn't really sound like high requirement. I don't need any higher bandwidth. Constant transfer is what's more important to me. Any drop below this value makes sound choke. When I'm looking at Tx/Rx every time i hear choke it drops to ~100kbps for a while. I've tried to do something with it: tried scanning channels and choose least busy one, changed channel width to lower, tried changing TDMA frequency to lower/higher/auto, Tx power to max and framer policy (not sure what it does) But i don't think it helped much. I know wireless is not 100% reliable and I probably won't be able to get perfect stability but I'd be satisfied with chokes less frequent than few per track (one per minte?). Currently it's choking all the time every few seconds.

I'm quite newbie in terms of networking especially wireless so I'd appreciate any hints about what to do but also about what to search for / read to educate. Atm I'm after CCNA course and one term of telecom basics at uni (more about mobile WAN networks than LAN).

If such task requires more specialized hardware than RB2011UiAS-2HnD and ThinkPad X200 wifi card then I'd be also graceful for recommendations in terms of hardware.

Posted: Wed Feb 24, 2016 6:49 pm
by jarda
It mostly depends on the streaming protocol. If it can be a bit delayed, why not to use some buffering for 1 or 2 seconds in advance? You have to always expect some interference...

Re: RB2011 stable, low bandwidth wifi - how to?

Posted: Wed Feb 24, 2016 8:14 pm
by lapsio
For music I could indeed use protocol with heavy buffering (or even store music on actual playback server which is already done, alternatively use cable which works fine for all stationary PCs and I'm using it when possible) but I'm passing through all audio in general, not just music, I'm using remote sound output sink so that whole sound in general is passed to central audio server with soundcard for all devices so in fact even latency > 100ms is annoying for games or various feedback sounds like clicking. Atm I'm plugging super long cable to laptop when it's necessary but it's not really perfect convenience, especially when I need to unplug it every time i go to kitchen or toilet :lol:. If it's not possible to eliminate choking I'd at least like to increase responsiveness as much as possible.

1st idea - reduce frequency range so interference will be more constant, but none of my wifi devices detect hotspot below 20Mhz range.

2nd - move to possibly free freq range (not really possible, quite busy area, I've chosen 2462 Mhz)
2383  -67 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.                       
2391  -67 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.                       
2399  -66 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.                     
2407  -51 ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.
2414  -69 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::............................................
2422  -69 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.....                       
2430  -75 ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.                                          
2438  -76 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::.........                                   
2446  -76 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::..                                          
2453  -76 ::::::::::::::::::::::::::::::::::::::::::::::::::::::::.                                            
2461  -75 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.....                                     
2469  -76 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::.......                                     
2477  -77 ::::::::::::::::::::::::::::::::::::::::::::::::::::::............                                   
2484  -78 ::::::::::::::::::::::::::::::::::::::::::::::::::::.......                                          
2492  -78 ::::::::::::::::::::::::::::::::::::::::::::::::::::.....                                            
2500  -71 ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::..........                       
2508  -77 ::::::::::::::::::::::::::::::::::::::::::::::::::::::...                                            
2516  -79 :::::::::::::::::::::::::::::::::::::::::::::::::.
3 - I've set one chain to Tx only, another one to Rx - i have no idea if it can help

And i still have few questions about other settings:

4 - What is the rest of settings in "HT" section for? I mean AMSDU and AMPDU stuff?
5 - What does HT MCS do?
6 - Are those "wireless protocols" relevant? I mean NV2 and Nstreme. I remember that Nstreme was proprietary Mikrotik technology for linking routers over wifi so probably not, but NV2? Is it used by end user devices or only networking hardware?
7 - What are Hw settings? (Hw. fragmentation, protection etc)

I think I understand the rest of settings more or less.
I'd like to "feel" this router a bit more, not just look at controls as some magic which somehow works.

Posted: Tue Mar 08, 2016 7:36 am
by jarda
Check the signal levels of clients at Ap and vice versa. Maybe the signal is too strong so you will need to reduce it. Use regulatory domain option, your country and set antenna gain to 4. Then check the behaviour and signal levels again. See the ccq too when the transfer is going for some time.

Re: RB2011 stable, low bandwidth wifi - how to?

Posted: Fri Apr 15, 2016 2:49 pm
by lapsio
I'd like to bump this thread because I've bought second mikrotik for second room and it didn't help much...

In matter of fact it's kind of terrible. At least on hAP it's pretty terrible. I'm getting even 70/80 Tx/Rx dBm on the distance of like... 2m in straight line from router:


I have tbh similar Tx/Rx results if i connect to RB2011 which is like in totally another room behind 2 walls... It's so bad signal that this hAP doesn't make sense at all. It made totally no difference in wifi usage comfort. Still stream is dropping from time to time. Best stability I could ever achieve was by using internal laptop wifi for internet traffic connected to one router (RB) and mAP with static routing configured to be used only for HTPC connection making second radio (mAP) and hAP dedicated wireless connection just for audio transfer. This way interference between download and upload was much smaller (because transfer almost doesn't drop at all in regular situation, drops occur when something starts using bandwidth eg YT starts preloading missing part of video after some time of playback, it's strongly noticeable in Tx/Rx diagrams in MT. Any download causes upload drop, even if it's far from maxing wifi throughput). If i go to my room and stay near RB I'm getting Tx/Rx around 40-50dBm. Considering some people say that anything below 70dBm is terrible i don't think it's normal behavior. There's my routers config that gave me best results so far:

set [ find default-name=wlan1 ] band=2ghz-b/g/n bridge-mode=disabled\
    compression=yes default-authentication=no disabled=no\ 
    frequency=2462 hide-ssid=yes mode=ap-bridge\
    name=wlan-root preamble-mode=long rx-chains=0\
    security-profile=secure ssid=- tx-chains=1 tx-power=30 tx-power-mode=\
set [ find default-name=wlan1 ] band=2ghz-b/g/n bridge-mode=disabled\
    compression=yes default-authentication=no disabled=no distance=indoors\
    frequency=auto hide-ssid=yes mode=ap-bridge\
    name=wlan-root preamble-mode=long rx-chains=1\
    security-profile=secure ssid=- tx-chains=0 tx-power=30 \
    tx-power-mode=all-rates-fixed wireless-protocol=802.11\
(ignore authenticate, it's master for many vwlans)

and mAP (station):
set [ find default-name=wlan1 ] band=2ghz-onlyn channel-width=20/40mhz-eC\
    compression=yes disabled=no distance=indoors frequency=auto frequency-mode=\
    superchannel ht-basic-mcs=mcs-0 ht-supported-mcs=mcs-0\ 
    l2mtu=1600 preamble-mode=long security-profile=secure-alt\ 
    ssid=Suse-alt tx-chains=0,1 tx-power=30 \
    tx-power-mode=all-rates-fixed wmm-support=enabled
mAP uses only BPSK so should force BPSK modulation in connection and both hAP, RB2011 have 20mhz channel width so should force this parameter as well.