Low NV2 802.11ac PTMP Thoughput

RouterOS Wireless Networking
1

Have an access point, netmetal running dual chains to 120 degree sector.

/interface wireless
set [ find default-name=wlan1 ] adaptive-noise-immunity=ap-and-client-mode band=5ghz-onlyn channel-width=20/40mhz-Ce default-forwarding=no disabled=no frequency=5265 ht-basic-mcs=\
    mcs-0,mcs-1,mcs-2,mcs-3,mcs-8,mcs-9,mcs-10,mcs-11 ht-supported-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-5,mcs-8,mcs-9,mcs-10,mcs-11 hw-retries=15 l2mtu=1600 mode=ap-bridge nv2-cell-radius=20 nv2-preshared-key=key \
    nv2-security=enabled radio-name=TD-120-East rx-chains=0,1 ssid=east tdma-period-size=4 tx-chains=0,1 wireless-protocol=nv2-nstreme

ss68 May. 07 15.51.jpg
As you can see 45 clients.

When we started with about 10 clients, we could get 50-60 meg per client, in ac mode.

Now with this, in a/n/ac mode we get less than 5 meg to each client, in N only mode we get around 10ish at most. we never see the access point go above 30 meg transmit!

All clients are SXTs, everyone is mostly above -70 .. clients with -60s are only able to get 6-7 meg if that.. in the evening is slows down even more with the ap only dishing out around 10-15 meg total.

Any help here? we turn on nstream, and get polling timeouts, and in 802.11 mode we barely can even winbox to clients :frowning:

2

You should try to make BWTest TCP client with the best signal.
In meantime you manual disconnect other users until you find the one (or ones) that degrade performance.

With Mikrotik often I found that clients, because obstacles, degrade the entire cell (even if the signal is good). They should work a little more on the protocol PtMP

In your case I would check
E7: 7D
76:15
72: C1

And remember that if there is an obstacle between a client and your AP mounting an high gain antenna, doesn’t solve the problem, improves the situation of course, but do not solve

I think Mikrotik can work even on two things:
1 - prevent the degradation of the cell if only one client has problem
2 - adjust the protocol (PtMP) to work even if there are simple obstacles (branches of a tree). Today if I have a -60 (which is a good signal) with 2km distance with a QRT5 the customer goes very wrong. If I have a -60dB at 6km, QRT (for example) going very well

3

Remove clientes over 70.

That CCQ’s are worst than bad. You’re not working in a clean frecuency.
Be carefull when scanning with the Ubiquitis sectors shifted +5Mhz, you can’t see them but they are there. I have a cheap Omnitik installed in nearly every places (with wlan1 disabled) only for scanning purposes.

Give a try using 20 Mhz channel width in sectors, it’s easy, fast and safe. Force some traffic to all the clientes, using ipscan tool for example, and then look signals and specially CCQ. Then, test some of the clients that you have previously tested and compare.

If better … start to change the AP frequency until you get the best quality and throughput in average.

Regards.

4

OmniTik as extra unit in AP location is a very good Idea I am using since some time.
Some advantages;

  1. If the PoE-out version is used you can power control 4 units remotely (or automated by script). Like 1x backhaul, 2-3 AP sectors.
  2. You can always perform a radio scan or Sniff. It won’t disturb the actuall working of the real AP’s.
  3. If you’d use any local traffic processing like mangle, filter, QoS, you can have it done by the Omnitik. Simplyfies the setup of the real AP’s and leave the real AP’s cpu free for traffic handling only.

If running a wireless scan or sniffer (sniffer ‘sees’ frequency usage not noticed by scan) make sure to do also a 10 and even 5Mhz scan.
I found an operator using several 10Mhz centre frequencies the same as my 20Mhz ones… (not very nice!)


Last, but not least:
Sometimes it can be it all looks fine at the AP. No close, or very weak, neigboring frequency usage scanned… but; it can still be that at the client its different!

We had one AP with only 8 clients, ranging 15meter to 300meter max in a town.
All clients had signals ranging from -50 to -35. But still we had one client with - 37 that had a very poor CCQ (5-20%) We had problems to bring more than 2Mb to the client.. but the scan on the AP didn’t reveal too much. Only one 10Mhz channel usage of competition 20Mhz beside our centre frequency and signal strenght measured at (at the Omnitik with is 7-8dBi antenna!) -88 - -93dB.

When we did a scan on the client we found that same providers AP hitting our client with -30dB! Stronger than our signal!
We swapped the AP frequency completely away and the problem dissapeared!


How to scan remote client in 10Mhz band while it should be connected to 20Mhz working AP?

  • Set 10Mhz channels in the client’s ‘channel list’.
  • Set in the scan part of the wireless both the AP’s centre frequencies and 2 or 3 adjacent 20Mhz channels.
  • Set in the scan part of the wireless also all 10Mhz frequencies from the AP’s frequencie and into 25Mhz to both ends.

Basically you have now setup a 50Mhz wide band for 10Mhz scanning, and a 100Mhz wide band for 20Mhz.

Now, log into the AP, open a telnet session to the client and run the scan;

int wi scan 0 d=10

The client will now scan for 10 secs in the channels given in the scan list of client.
Client will disconnect but when it comes back, and after some time (10-30 secs) the telnet session in AP comes alive again and will show the result of the scan!

Now you can see what is actually happening around the working frequency of the AP, but AT the client!

Good luck! :smiley:

5

Lately sort of discovered the spectral scan tool. I knew it existed but never really took a good look into it, until I found that a normal scan doesn’t see a lot and you need to set the scan frequencies in the ‘scan’ portion of the unit you need the scan off.

What I do now is do a remote (so from the AP’s winbox session I open a telnet session to the client) frequency-history. You set the range and some time frame. Let the scan run for instance 30 secs after about another 20secs or so the remote unit returns the results in the telnet winbod. (The telnet session doesn’t break, like a winbox session does. A telnet session just waits until unit comes backup, even after 5 mins…)

So, find the IP of the CPE and open under / tools a telnet session (there are other ways to open one but for simplicity this one)

after typing your admin and password the remote unit opens in telnet window (that runs in the AP winbox session)

type

int wi

the unit opens in the wireless interface menu section,

pr

and the unit returns with the wireless interfaces and its setting,

spectral-history 0 range=5100-5950 d=30

Now you’ll see the CPE disconnect after some time but thats normal. Wait until the CPE connects again and wait about half a minute more (depends on how good the connection to CPE is and how many other CPE’s connect to AP)

Now, after this time the still open telnet window (before typing the codes to do the scan widen it to the whole screen, that gives best resolution) shows the spectral scan result in color! Very nice. You probably see a yellow or red color band where your AP is transmitting and all other signals around. Now you can see if your spectrum at the client is really used and if there is anything free you might think to move…

To guarantee that another 3rd party source is not interfering with your AP’s working frequency you can switch your AP’s radio off for about 20 secs just after the start of the CPE’s scan.
In the graph you can now see your AP’s spectral usage drop off and come back. If it still shows yellow colors close to your AP’s working freq. even when it was off, you know some other frequency is disturbing yours…


The advantage of this spectral scan is that the scan setting in the wireless part of the radio at the CPE can be left as it was. I usually only set the frequency of the AP so the CPE comes back asap after a disconnect. It doesn’t have to ‘search’ in the band for the AP.

Second advantage is that the spectral scan will pickup ‘any’ frequency (802.11? I actually don’t know about non 802.11 radio sources) in the band. 5Ghz, 10, 20 or 40 and with or without shift.

You can do the same in the AP or other CPE’s to see if other places are bothered by the same interference sources.

In the AP I also do a scan with 10 and 20Mhz wide channel. It gives me the names of the other networks so I can identify which network is the one that disturbs mine! (I found to my shame at some occasions it was actually one of my own! But ok, I use 50 different radio’s!)

Now, one reason why an omnitik is a very good idea to have at your AP: MT 802.11ac can’t do the spectral scan!
So, if all your CPE’s are also ac than your thrown back to the use of the ‘scan’ tool in the winbox. That’s a lot more complicated to do and doesn’t give all the info you want…

I really don’t understand why bringing back the spectral scan tool in ac units again. But I’ve been told its more a shortcoming of the chipset than the software…
But for me its one reason why I still won’t use any ac CPE units. What is the use of ac in PtMP networks if I hardly can ‘see’ what the spectral situation will be.
ac is partially a solution for spectral issues, but you need a tool to at least use it than to the advantage. Now its not…

6

The basic problem is that when you connect many customers on a cell the bandwidth decreases drastically.
I have the same problem, about 45 clients connected with optimal signals, but I can not pass over in 6-7Mbps TCP in download (test on the customer with best signal)
The access poin at that time also gets little traffic (10-12Mbps) and with my test coming to a total load of up to 20Mbps.
The absurd thing is that if I leave only this customer attached on the cell, it arrives at 40-50Mbps TCP.

I am increasingly convinced that the NV2 protocol in PTMP mode has not been optimized.
It seems that when a CPE is not in optical visibility (although with good signal) this goes to heavily degrade the cell.

There isn’t interference on that frequency

7

As I stated many times on this forum, more than 20 stations on a mikrotik AP will result in very low bandiwth, high ping and also serving timed outs to clients. NV2 is not good, nstreme the same.
With nv2 and 15 stations have ~15ms average ping at ~30-50mbps trafic.
I can’t imagine 45 stations…

8

If 40 customers share 60-70Mbps overall bandwidth then OK, it’s saturation.
But, if 40 customers are not making traffic and, just for the fact of being associated with the AP, degrade the performance of all, mean that there is a problem to resolve, especially if a station reach max of 8-10Mbps when on AP there are only other 2Mbps

For example I have a BTS with 8 Mikrotik cells, each charge from 25 to 45 customers and I really see how it is behaving.
I can not add more cells for lack of frequencies.
I’m realizing that there is no solution with Mikrotik.

I asked many times to improve performance in wireless technology for WISP, but they doesn’t seem to have an answer.

I saw other providers use the Cambium Network PMP450 and connect 100-120 customers on a 20Mhz cell and I see customer on that, reaching bands of 40-50Mbps with incredibly low latency

There are ways to improve and I think the Mikrotik team knows them, just not seem to develop.

Unfortunately, I have areas where I do not have ability to create other BTS and new customers continuously to arrive, but I have no possibility of growth.

It would be good news if Mikrotik announced that they are working on something on the wireless world for Wisp (eg GPS Sync) so I can stay with them, but this is only a hope… :frowning:

9

Can’t agree more with you guys.
In the ‘old’ days, when tdma was grown out of its initial problems it worked very good for me with some AP’s up to 40 clients, single chain even so!
But now with the tough competition from more operators to serve more clients that on average also are more demanding we are running in the same ‘trap’ as mentioned here. Too many customers with too many bandwidth assigned to them in a too crowded spectrum.

Did we offer ‘up to 6Mb’ speed for top contracts 2 years ago, that is now considered basic.
If clients didn’t get their ‘top’ speed regularly two years ago, hardly any complained. For an occasional download of a movie or photos or some occasional browsing not such a big deal. The network performed relatively well too so not a lot of complaints. Nowadays it looks like some make it their habit to open their PC with www.speedtest.com and if its not top, I’ll get the message…

At the same time came the many, many (50 -80 up to 200Mbps) deals from the big carriers in the big towns, and together with the push to buy the smart TV with the embedded streaming video and TV options that people wanted to use, even if they went to live in the country side, people expected that kind of internet to be available everywhere.

“I bought this internet smart TV but it doesn’t work”… “Well, you have a basic contract with a poor connection that can only do your assigned 2-4 megs…”, … “Well, that ain’t good enough, the shop told me my 50” 3D HDTV should also work in the country side…" :frowning:

And oh yeah, now he complained anyway, amidst the crisis; “How can it be the competition offers double the speed for half the money?” “Maybe I should go swap operator??”

Every customer we loose needs two new ones just to keep up with the income…
And more new players entered the market, with new lower priced contracts and new towers working in the same band molesting my towers…

Same time this country (Spain) was years behind compared to the North of Europe, special in the country side, but that is now being corrected very fast. So still we are getting new clients every day, once we need just to get the money in to upgrade as good as possible our network…

So here is the problem. Existing networks have to deliver more bandwidth in worse spectrum to more clients for lower income per customer.
I found out indeed 25-30 per AP is going to be an absolute max. and only the best antenna’s are good enough to get as much as possible out of the spectrum.
With Mikrotik it is becoming a very difficult task and as I am being told with ubnt its not so much the better.
Some on this forum actually also stated that during a MUM he spoke with one of the MT guys and it was actually confirmed that wireless was not really one of their focusses… so that makes you to start thinking…

I already looked at Cambium, looks very promising, or what to think of Mimoso. Looks even better.
But where the hell to find the money and the time to change my network…

10

I confirm this some problem. (on noisy area, and more >15 clients on ap)

and on the new controller “wireless-fp” Pings little better on NV2, but the stability is worse.

In the old driver more kept connection.
On the new lot more disconnects in the noisy area.


I hope that implementation can improve MU-MIMO case.
If not, unfortunately, we will need to migrate to another manufacturer.

11

I’m already considering another supplier.
I think that Mikrotik never improve its system for wisp

I begin to have many customers and situations of degradation are more and more.
Are ONLY two years in which I hope some improvements:
(http://forum.mikrotik.com/t/as-we-would-like-to-evolve-the-wireless/69307/1) Sep 04, 2013

I will look MUM Friday what they show, but will be the usual products

Pity, for € 15,000 (sxt, sextant, qrt, netbox, netmetal) of material that I order every month, go into other pockets

12

It’s very disappointing to see that there isn’t a single word from a MikroTik guy about that :frowning:

I invested lots of money in MikroTik for my network and I don’t see nothing they do to tell us how to improve performance in PtMP.
If they think performances are ok, they could write a wiki article about how to set up a good performing sector with more than 25-30 users on it.
Competitors performs better than MikroTik with the same spectrum and more users.
Cambium states they can reach up to 120 customers on one sector. On MikroTik that’s impossible!

I hope they have a solution for that. They can’t leave all WISP alone without solutions to grow.

I wouldn’t like to go with Cambium, because it would mean change all my existing SXT and so on… And I like MikroTik system, but they have to improve wireless a lot!

They released some sectors, maybe they are preparing something new for PtMP?
Maybe a new protocol in RouterOS 7 which will help?

MikroTik, please, give us some feedback!

13

We have APs 20Mhz with 50+ clients. Signals are under -50 with only some clients over -60. The AP has a maximum aggregate of 50 Mb/s in dramatic high noisy enviroment.

Client side bandwith test reach 50 Mb/s with signal around -40 and only 7 Mb/s with signal around -65. Generally we use shielded SXT AC 90° as AP and high gain antenna client side.

We apply queues client side: with good signals (under -50) we give 10/1 Mb/s with bad signals (over -65) 3 Mb/s/512kb/s. In this way clients with bad signals don’t takes airtime to retrasmit loss packets they have slow connection.

I hope to see soon NV3 and sink.

Giuseppe

14

How did you configured queue client side? Did you find it faster than AP side?
You could post your configuration here if you want: http://forum.mikrotik.com/t/best-ptmp-configuration-on-mikrotik/94879/1

15

Well i had been facing exactly same issues with Mikrotik NV2,performance degrades after 25-30 clients,latency keeps between 15-20 ms.

I have made following changes to my network and now everything has returned to normal. You can try these changes and check if it helps you.

  1. all client’s are kept in between -50 to -60 range
  2. upgraded all sector anteenas to ubnt ac 60 degree 21 dbi powered by basebox 5
  3. changed ap settings to nstreme as discussed in this post
    http://forum.mikrotik.com/t/nstreme-over-n-40mhz-dual-chain-links-solved/75445/1

Surprisingly nstreme never worked for me with default settings but with this modified setting it is working amazingly fast with no disconnections.Version currently being used is 6.33.5

Also i run my ap’s on 10 mhz channel and max bandwidth i provide is 10/10 Mbps.

Currently have deployed this over 45 sectors and 10 PTP running combined bw above 500 Mbps during peak hours.

16

How much users can you put on a sector with this configuration?
What about limiting users? Do you have default queue types?

17

Since i have been testing this new config for last 10 days currently all sectors are having subs in between 25 - 35. Am planning to add more and test the result. Till now everything is working smoothly.

18

Can you tell us how do you make limitation to users? Simple-queue on AP? PPPoE?

19

I have a sector with 45 Clients also used to perform like garbage no matter what frequency.

Two days back we had a lightning storm and I think it killed one of the other providers neighboring tower.

Client with the worst signal -77/-72 now gets 13Mbps down and 2 up Client with the best signal -51/-47 now gets 35Mbps down and about 21Mbps up.

This is on 20Mhz wirless a/n with a HT MCS 7.

I’m expecting the performance to become cancer once the other providers tower gets fixed.

They do 40Mhz full power 31dbm, complain to the Communications Authority and they do nothing about the problem that a unlicensed wisp is taking up all the spectrum.

20

We use client side queue like this

/queue tree
add max-limit=10M name=ether1-root parent=ether1
add max-limit=512k name=wlan2-root parent=wlan2

In this way all AP cpu power is used for NV2.

Giuseppe