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ktw-matt
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RB532, CM9, and high pings

Fri Mar 03, 2006 10:22 pm

Hi everyone.

We were running an AP-2000 access point and seperate x86 MikroTik router at this one tower site, and it worked good.

We're now trying out the RB532+CM9 MikroTik Router/AP combo box at that site, and, while I'm impressed at how much snappier my connection at home feels while connected to this AP/Router combo, I am seeing spikes in ping times to not only my wireless client antenna, but for other customers. (Ping tests were done from the wired end - which actually plugs into a 5GHz backhaul.)

I'm seeing ping spikes of up to atleast 125ms ever 3 - 5 seconds, somtimes it'll go maybe 15 - 25 seconds before you see it spike like this.

I like to play Quake2, and I can watch the Quake2 "netgraph" to see when it happens. (It's not the gameserver nor my route - its the AP/Router combo, because I also see these spikes when pinging the AP/Router combo from home - or from work on the wired side.)

My game just like everything else on my connection moves along alot quicker with this setup, which I love very much, however, these ping spikes cause my game (and everything else I imagine) to stutter for approx. 50ms (I'm guessing). It's not fun for me nor my opponents to see that.

Otherwise, my connection to this tower is doing so much better... now if we can just iron out the ping spikes with it. :?

Ok, here are the details:
- Wireless clients to this tower are all 802.11b
- CM9 wireless card is running in ap-bridge mode set to 2.4GHz-B running on Frequency 2447 (Chan 8 I believe)
- Supported B rates - I have all of them checked
- Basic B rates - I have all of them checked
- we're not doing encryption, WDS, or Nstreme; we just have a 15 dBm omni antenna on the tower broadcasting this 802.11b signal.
- we've got the wireless client antennas configured for static private IP's, but the customer is configured for DHCP (gets a public IP)
- we're doing RADIUS authentication on the wireless and dhcp; we authenticate on the wireless by their antenna's MAC address and we do the same for the customer's PC/Router with DHCP.
- the wireless interface (wlan1) has its ARP set to reply-only, and we're putting the wireless client antenna MACs in as static ARP entries, while the DHCP server is setup to add the ARP entry.

Now, the ping spikes and/or overall connection quality seemed to improve some after I enabled all Basic B rates. (This was with all Supported B rates already enabled by default.)

Is there anything left that I can try out here to solve this?
Last edited by ktw-matt on Sat Mar 04, 2006 1:52 pm, edited 1 time in total.
 
ktw-matt
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Sat Mar 04, 2006 11:36 am

I realized earlier that I didn't have frequency-mode=manual-tx-power, when I had already configured tx-power-mode=card-rates and tx-power=18 (that of the 65mW CM9 card in 2.4GHz).. so I set that to manual-tx-power, and then attempted to lower on-fail-retry-time to something lower than 100ms, thinking maybe I didn't have as good a link to the AP as I thought and that this was where most of my ~125ms ping times are coming from.

Unfortunately, it wouldn't let me change to even 75ms, as well I'm still seeing these ping spikes here and there, sometimes with it acting like the connection's bandwidth has been maxed out (basically starts acting like *it can only recieve* but not send very well.)

With our old setup, like I said, we used an AP-2000 access point from Proxim, usually with Orinoco PC Gold cards, which I think my boss said is a 100mW card... and that's the conclusion I'm coming to, that maybe the CM9's 65mW just isn't enough juice for me.

That CM9 in the MikroTik AP is hooked up to a 15dBi omni antenna with an amp (though I don't know how much power), and then I'm using a YDI/Terabeam/Proxim EtherAnt II Long Range antenna at my home (its an 18dBi directional panel antenna with a built-in amp, making the EIRP somewhere in the 40's on this CPE, I think). The EtherAnt II gets atleast 10miles I believe.

So, do you think getting a higher power card like the SR2 would help us out?
 
ktw-matt
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Sat Mar 04, 2006 2:01 pm

After reading thru some of the recent posts here, I've tried the following:
* Set my EtherAnt II-LR to 'Automatic' (only other options are 2 and 1Mb).
* Disabling the QoS feature on my Linksys WRT54G router (home router).
* Upgraded the RB532 Router/AP combo, 2.9.12 => 2.9.13
* Disabled wireless package in favor of wireless-legacy (this resulted in no one associating to our CM9 - AR5213 card; I've since swapped it back to the wireless package and people are associating correctly again)
* Changed preamble-mode from 'both' to 'long' (it says long is 802.11 compatible, but 'short' isn't)
* Changed from channel 8 to channel 11 (chan 11 is what our AP-2000 auto-selected for us when it was in use)

And after all of this, I think I still have this problem, though I will say it looks like its improved. (But who knows, it might've just improved because its so early in the morning -- no one's hardly using it, as I had hoped for, for reconfiguring this thing.)

This is my stopping point folks..

Any ideas ?
 
ktw-matt
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Sat Mar 04, 2006 2:16 pm

Err.. Let me clarify how the ping spikes are acting.

From a command prompt, pinging the MikroTik Router/AP you simply see anywheres from 60ms on up to atleast 120ms in every 1 of say 20 ping replies. The other 19 of 20 ping replies are all comfortably at 3 - 7ms.

It doesn't look like such a big deal at first, but if you try to play a game like Quake with this, here's what happens: you're watching the in-game network graph - it spikes; well, ok, that one was minor; 15 seconds later it may do it again and this time you might see "hills" being drawn on the game's netgraph and guess what - you're barely able to move in the game until it clears up maybe a minute or two later. NOT cool to say the least.

So while I'm having a hard time even playing the game while that's happening, I see the other players moving along just fine.

What's going on here?
 
mikapojic
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Sat Mar 04, 2006 2:36 pm

You could try locking down your clients datarate to lower rates. It could improve your ping.
 
tully
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Sun Mar 05, 2006 12:33 pm

This is the reason for your problem.

- Basic B rates - I have all of them checked

You must set the basic-rate to only 1Mb/s -- and don't change anything that you don't understand.

John
 
ktw-matt
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Sun Mar 05, 2006 11:20 pm

I turned on the extra Basic B rates, after the fact, in hopes of it improving. It has atleast made the connection seem a lot quicker. What can I say, I was desperate.

I'll try turning it back down though.. Thanks.
 
ktw-matt
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Mon Mar 06, 2006 5:09 am

Well, that didn't do it either.

I managed to run a traceroute from a website while this was happening one time, and from those results, it appears to be a problem with either the backhauls or the MT router.

I had a friend traceroute me another time it happened, and he said it was just on the last hop -- my Linksys router at the house.

Speaking of which.. maybe I'd better take my router out of the equation.
 
ktw-matt
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Mon Mar 06, 2006 6:02 am

It's not my linksys router. I'm wired up outside of my router and it still does it. This time when it happened, I went back to that website where I ran ping and traceroute tests to the MT router. Thing showed pings of 250ms up to 1150ms. (Pings were fine up until it pinged the MT router).

That tells me for sure that its either the backhauls or the MT router out there.

Currently, I can't get access to the backhauls so I can't check for that.
However, I've also got the router setup to graph its resources.. and I have noticed CPU usage on the router spike from about 12% to 48% sometimes while this was going on. (Didn't happen the entire time the ping spikes were going on though.)

Heh, I was chasing my tail the whole time on this subject.

By the way, there's only like 10 - 15 people on this access point.
Anyways, I'll keep watching these two and update you.
 
ktw-matt
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Mon Mar 06, 2006 7:57 am

It appears to be a problem with one of the backhauls - from the router I get a consistent 3 - 7ms to one of them, but the other one - when its acting up, soars to nearly 1000ms, and often hits 256ms on up to 500ms.

Geez, this was the last thing I would have considered. :oops: Especially since everything worked fine *before* putting in this router+AP combo box.

Though, come to think of it, I do remember seeing atleast one of the backhauls do this recently - just not on this scale. I'd imagine there's water in a cable or something somewhere.

Sigh. Thanks for putting up with me.. :roll:

For the record, my antenna's signal to the AP is pretty darn consistent. I just wonder why my pings to the AP go up when the backhaul from that tower to the main one acts up, unless there's more water than I thought ...
 
ktw-matt
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Mon Mar 06, 2006 7:33 pm

There's two parts to this:
1) ping spikes (150 - 200ms) from me to the AP (from a normal 4 - 6ms); occurs atleast once every minute.
2) difficulty sending but no problem recieving, accompanied by outrageous 1000ms pings; occurs atleast twice an hour and lasts for several minutes.

Last night, I had it figured to be the backhaul link that was causing #2. Maybe it is, maybe it isn't.. I just know I'm not seeing it this morning. (While we were at it, we changed the frequency of the 5GHz backhauls.. maybe that'll "fix" problem #2.)

As for #1, here's what I'm seeing from work:
- pings from my computer at work to the backhaul (A) up top: <= 1ms
- pings from my computer at work to the backhaul (B) at the other tower: 1 - 9ms; usually 1ms
- pings from RB532 at the other tower to its backhaul (B): 4 - 6ms (is this normal? I know older/slower machines have high pings from themselves..)
- pings from RB532 to backhaul (A): 4 - 9ms

Then there's this:
- pings from my computer at work to my antenna at the house: 3 - 6ms; spikes as high as 150ms on average, atleast once every minute; sometimes more often/worse.

Problem #1 doesn't appear to be the router nor the backhauls...just the wireless link from my antenna to the AP. But, my antenna's signal (-55) seems pretty consistent.

So any thoughts? :(
 
muehlbauer
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ping

Tue Nov 14, 2006 3:57 am

This is an old thread so ignore if your not reading.
Your wireless works on half duplex. One problem with your sporadic high ping time could be latency induced by the AP being busy sending or reiciving someone elses packets.
An isolated test would be to hide SSID, make sure no one else but you is Ack'd then try your ping test. I would suspect, all other things like noise and such being equal, you should find some pretty consistent times.
 
maxfava
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Sun Nov 19, 2006 8:35 pm

I'm having the sporatics high ping on 3 station(RB532+CM9) on the 2.4Ghz.
On the 5GHz I have no problem.

I have tried all, and at the end, I solved reducing the traffinc of my customers to 500 Kb max for access point.
Before of this setup I have used with success DLINK 2000AP+ with only the issue of the endurance but not for performance like as now I'm encountered.
 
ropeba
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Sun Nov 19, 2006 9:23 pm

I have same problem with CM9. Till he was dwl-2000+ everything was working good. I try to set mikrotik in client wds mode and d-link 2000+ in ap mode but no one cannot connect on d-link as long as he is connected to mokrotik via ethernet.
 
ropeba
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Sun Nov 19, 2006 9:41 pm

CM9 is working fine on ptp links but when it's about AP for more clients it shows that it's really bad card. with -56 % of signal ping goes over 300ms. I plan to buy SR2 and I hope that she will be better with AP on which about 10 clients are connecting, on 2.4
 
ucheonyeaka
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Mon Nov 20, 2006 3:44 pm

ktw-matt,

Have you solved your problem?
 
maxfava
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Thu Nov 23, 2006 12:35 pm

CM9 is working fine on ptp links but when it's about AP for more clients it shows that it's really bad card. with -56 % of signal ping goes over 300ms. I plan to buy SR2 and I hope that she will be better with AP on which about 10 clients are connecting, on 2.4
I have this think too, but I never use SR2 or SR52.
(MK team has not provided feedback)
I will wait your feddback before to buy other cards.
Meanwhile I will try other ways.
1) Next week will arrive new 5006x chipset, I will try it as AP,
2) also today I'm going to plug a mPCI card used on the 2000AP+ into RB523. I hope that the RB support Texas Instrument Chipset.
3) I want to try INTEL chipset PROSET 2200 wireles mPCI of my laptop monted on the RB.
 
maxfava
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Fri Nov 24, 2006 1:51 pm

ropeba
are you Italian guy, right?

mail me public[chiocc]maxfava.com

Ciao
 
ropeba
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Fri Nov 24, 2006 2:28 pm

ropeba
are you Italian guy, right?

mail me public[chiocc]maxfava.com

Ciao
no, Bosnian ;)
 
ropeba
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Sat Nov 25, 2006 9:50 pm

maxfava,

did you try plug a mPCI card from 2000AP+ into RB523?
 
cibernet
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Sun Nov 26, 2006 4:15 am

2) also today I'm going to plug a mPCI card used on the 2000AP+ into RB523. I hope that the RB support Texas Instrument Chipset.
3) I want to try INTEL chipset PROSET 2200 wireles mPCI of my laptop monted on the RB.
Those chipsets are not supported by MikroTik. check here http://www.mikrotik.com/docs/ros/2.9/gu ... tent#1.2.3 about the supported interfaces

Best regards
José Ignacio Acosta
MikroTik Consultant IDAR0001
Mikronet

Movile: +54 9 3472-624722
Email/Msn: info[at]mikronet.com.ar
 
ktw-matt
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Mon Nov 27, 2006 10:08 pm

ktw-matt,

Have you solved your problem?
I believe so. What we ended up doing was trying out the SL/NL-2511MP PLUS card. It seems to be much better than the CM9, atleast for AP use.
 
maxfava
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Mon Nov 27, 2006 11:13 pm

Hi all,
sorry for the delay, but day by day I working on towers to understand where is the issue of this terrible problem.
Pratically I have 3 point RB112 + 2xCM9 connected via 5GHz.
1 CM9 works at 5GHz without problem (backall) and on each RB112 the other CM9 is configured as bridge AP at 2.4Ghz.
Each point has a antenna Directive for the 5GHz and an OMNI at 2.4GHz, where are connected the customers. All APs are distance 500meters.
Each AP has maximum 8 client that use dlink 2000ap+ configured as clientAP.
Pratically in these days I discovered that all 3 APs works on the channel 3, until today :( instead today I have to switched to channel 4 to not have high ping.
Now I have reduced P2P traffic to min amount in download and upload (500K) and the problem is the same. If I disconnects all customers(VPN) without traffic on wireless the ping come below 20 ms.

I'm disperated.
The trials that before I want to try, I hope that in this week I will try.
:( :( :( :( :( :( :( :( :( :( :(
 
maxfava
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Tue Dec 05, 2006 8:32 pm

Hi all,
1) TI miniPCI card not works on RB.
2) INTEL PRO 2200G miniPCI not works on RB
3) I remove the CM9 card and I have try with new 5006x Sparklan: results are worst than CM9.
4) I have discovered that tower away 100 m with antennas in different area, on the same channel do not works in AP bridge
5) I lost another 2 customers
6) I'm wait for RB52 next week.
7) I want to try with WDS if it manage interferences.

thansk all.
Massimo
 
galaxynet
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Wed Dec 06, 2006 4:49 pm

ktw-matt -
That CM9 in the MikroTik AP is hooked up to a 15dBi omni antenna with an amp (though I don't know how much power), and then I'm using a YDI/Terabeam/Proxim EtherAnt II Long Range antenna at my home (its an 18dBi directional panel antenna with a built-in amp, making the EIRP somewhere in the 40's on this CPE, I think). The EtherAnt II gets atleast 10miles I believe.
1) You can't use an amp on an RB. It throws all the timing off. Use an SR2 card for more power and get that amp out of there. The reason your are seeing those high ping times is the RB is calibrating TX/RX ack times every 60 seconds - the amp throws all the calculations off....

2) Do a frequency scan using your 2.4Ghz card at the AP. See what channels are used, and use an un-used or low use channel. Your APs should never be on the same channel. And remember there are only 3 non-overlapping channels - 1, 6, and 11.

3) Set you card TX power to default - RB knows how to set the power - manual power settings sometimes screw up the actual card output (especially w/the CM-9) and can actually damage the card.

Thom
 
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Fri Dec 08, 2006 12:36 pm

We've realized this high pingtime ussue with Mikrotik for a long time now. Yet, it seems the while the ping-time is high to the tower, it is normal to the gateway Linux server. The ping-time to the client units also fluctuates when the client is sending/receiving data. One thing to keep in mind, most APs have prioritized ICMP. So, they always provide you with low ping-times, even in high traffic. Though, that doesn't mean you are getting a lot more bandwidth through.

On Mikrotik, the high ping-times to the client can be because of the queues set on the client or for the client. With ICMP not prioritized, the client connection may peek, and ping packets can be queued, thus ping-time may rize.

Yet there is also the issue of processor power. I have seen on RBs a 100% processor consumption everytime a client connects and disconnects. Before the RBs, I was running a PC ROS, and didn't really have this problem. So, everytime the processor peeks, it doesn not respond to other processes, ie ping replies can be delayed, and that's where our pings can jump upto 1000+ ms for a second.

However, the ping times to the gateway server seem steady with smaller fluctuations. So a question is raised. Does MT prioritize Forward chain by default?
 
maxfava
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Mon Dec 11, 2006 12:44 pm

Hi,
In my network, when I saw high pingtime, the connectivity goes slow too. On the AP the signal is good for all clients (-60 to -70) but CCQ goes 30 or 10. When network works fine the ping are 1-2 ms and CCQ is 90 with the same signal.(Also the SNR is good between 20 to 40).
The only parameter that I can move is the P2P bandwidh limitation on the root Server, but the limitation is too much (total 500Kbps/500kbps).
Now I monitoring the 4 sectors that I have made, each sector has from 5 to 10 customer in FWA.
All sectors are in different channels and far each other 600 meters and are connected via 5GHz.

ACK is indoor for all.
To reduce the intermittend high ping I slow down to 800.11B mode only.

Yesterday the network has work fine for 3 hours with 1Mbit up/2 Mbit Down of P2P for each sector(total 3 sectors). While ping time were between 1 ms to 100 ms. But after that the high pingtime have been showed by a sector, while the other 2 work fine, so I reduce the P2P to 500 Kbit again to stabilize the network. If I change the channel in this sector the problem is the same.
Yesterday was sector 1 may be today on the sector 2.
In this week will arive the R52, I hope that it help.

I'm sure
I don't think that slow ping depending from prioritize traffic.
 
triac
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Mon Dec 11, 2006 1:40 pm

Hi max,

-Galaxynet words: "Your APs should never be on the same channel. And remember there are only 3 non-overlapping channels - 1, 6, and 11". This is the first law.

Which is the distance between 2.4 AP antennas?

How many CPE for every AP?

Which is the distance from AP and all CPE's?
(Example: first CPE about 200 mt from AP and last CPE 5 Km from AP isn't good situation for good features...)

There are some interference source near CPE's or AP? (like 2.4 GHz audio/video sender or some shit like that).
Last edited by triac on Mon Dec 11, 2006 6:13 pm, edited 1 time in total.
 
maxfava
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Mon Dec 11, 2006 5:07 pm

-Galaxynet words: "Your APs should never be on the same channel. And remember there are only 3 non-overlapping channels - 1, 6, and 11". This is the first law.
Sure, channel 1, 6 , 11. or 1, 7 and 13, ok perfet.
but in my case the better I found is only between channel 1 and channel 4
Instead each sector work no good on channel 5, 6, 7 ....11. Spectrum analizer perfect clean. I do not know, it is too strange.
if I use the old DWL2000AP+ with the same cable and antenna all is ok.
Which is the distance between 2.4 AP antennas?
between 100 meters and 400 meters
How many CPE for every AP?
average 20 customers
Which is the distance from AP and all CPE's?
(Example: first CPE about 200 mt from AP and last CPE 5 Km from AP isn't good situation for good features...)
as before between 100 meters and 400 meters
There are some interference source near CPE's or AP? (like 2.4 GHz audio/video sender or some shit like that).
I have check with Spectrum analizer, all is ok. The AP is on top of a very tall building. Could be interference from very far city (40km)

ok rimuovi la mail se no la spannano.
ti ho mandato una io.

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