Point to Point setup?

RouterOS Wireless Networking
1

Hello,

I’m new MikroTik, however I have a reasonable amount of Ethernet and RF experience. I am planning to use a series of RB153s equiped with r52 wireless pci cards to provide comms to about 7 remote sites. Due to the nature of the terrain the topology will be an open ring if you like, site 1 will be linked ptp to site2, site2 to site3, site3 to site 4 and so on.
The equipment was meant to be provided to us as a turn key setup, unfortunatly this hasn’t worked out so now I get to sort it out.

Initially they were setup to be WDS ap-bridges, my initial question was whether this would limit the capacity so I have done some tests. The routers are setup on the bench with low gain whips attached, the rx levels are about -47 (I’ve knocked the Tx back to drop the rx level).

With this setup I see a throughput that is maxing out at 6Mbps, the wifi cards are connected at 54Mbs and the ccq is 100% and stable. From what I’ve read I should be seeing something more like 25Mbps throughput, would this be right?

Would I be better off running them at bridge and station mode?

I have tried to set the links up one as bridge and one as station and the results are not good, I’m getting and asymmetric connection, 54Mbps/6Mbps on the station side, with ccq of 100/75 (have seen 100/34). This happens on every link I setup with this same config so it must be in the config.
Here is a dump of the wireless config.


This is for the Station end.

0 R name=“Tussock Ridge to Waipori Radio 1” mtu=1500
mac-address=00:80:48:45:FA:25 arp=enabled disable-running-check=no
interface-type=Atheros AR5413
radio-name=“Tussock Ridge - Waipori Radio 1” mode=station
ssid=“WPI-TR1” area=“” frequency-mode=manual-txpower
country=no_country_set antenna-gain=29 frequency=5825 band=5ghz
scan-list=default rate-set=default
supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,
54Mbps
basic-rates-b=1Mbps basic-rates-a/g=6Mbps max-station-count=2007
ack-timeout=dynamic tx-power-mode=default noise-floor-threshold=default
periodic-calibration=default periodic-calibration-interval=60
burst-time=disabled dfs-mode=none antenna-mode=ant-a wds-mode=disabled
wds-default-bridge=bridge1 wds-default-cost=100 wds-cost-range=50-150
wds-ignore-ssid=no update-stats-interval=disabled
default-authentication=yes default-forwarding=yes default-ap-tx-limit=0
default-client-tx-limit=0 proprietary-extensions=post-2.9.25
hide-ssid=no security-profile=Trust Power Security
disconnect-timeout=3s on-fail-retry-time=100ms preamble-mode=both
compression=no allow-sharedkey=no


This is for the Bridge end


0 R name=“Waipori 2a to Tussock Ridge 1” mtu=1500
mac-address=00:0C:42:05:23:5F arp=enabled disable-running-check=no
interface-type=Atheros AR5413 radio-name=“Waipori 2a Radio 1”
mode=bridge ssid=“WPI-TR1” area=“” frequency-mode=manual-txpower
country=no_country_set antenna-gain=29 frequency=5825 band=5ghz
scan-list=default rate-set=default
supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,
54Mbps
basic-rates-b=1Mbps basic-rates-a/g=54Mbps max-station-count=2007
ack-timeout=dynamic tx-power=5 tx-power-mode=card-rates
noise-floor-threshold=default periodic-calibration=default
periodic-calibration-interval=60 burst-time=disabled dfs-mode=none
antenna-mode=ant-a wds-mode=disabled wds-default-bridge=Bridge
wds-default-cost=100 wds-cost-range=50-150 wds-ignore-ssid=no
update-stats-interval=disabled default-authentication=yes
default-forwarding=yes default-ap-tx-limit=0 default-client-tx-limit=0
proprietary-extensions=post-2.9.25 hide-ssid=no
security-profile=Trust Power Security 1 disconnect-timeout=3s
on-fail-retry-time=100ms preamble-mode=both compression=no
allow-sharedkey=no

Can anyone point me to where I may have gone wrong?
Any help would be greatly appreciated.

2

Mikebarnes -

I am planning to use a series of RB153s equiped with r52 wireless pci cards to provide comms to about 7 remote sites. Due to the nature of the terrain the topology will be an open ring if you like, site 1 will be linked ptp to site2, site2 to site3, site3 to site 4 and so on.

If you do not need to have a real bridged network then your best bet would be to go to a purely routed solution. This will require two wireless cards and the appropriate antennas at each site but you’ll get some real throughput. One of the issues with WDS is that at each connection down the ‘pipe’, if you will, you lose approximately 1/2 of your throughput. Meaning that if you start with 20mbps at site 1, site 2 will only have 10mbps, site 3 only 5mbps, etc - you get the picture…

Next - how are you testing your throughput? Are you using the RB builtin BW tester? If so then the CPUs on your RB153s are maxing out before you reach the full potential of the connection… Best to use MT BW test windows client on two PCs connected at the ends of the wireless setup. This will give you a much better picture of what you can expect to get under optimal conditions (I say optimal as you are testing this is a lab type environment - not out in the ‘wild’ as they say).

I have not used the RB153s but I have several of just about every other RB made so you are about right when you say you should be able to push/pull about 20mbps. It’s all based on the CPU processing power and of course the limitations of the wireless protocols themselves. CPU cycles get eaten up with everything you add for it to do, encryption, connection tracking, firewall rules, etc, and it has to ‘format’ the data for the wireless cards too - you get the picture.

Well that’s it for now - come back anytime - you’ll get answers - not always right - but you’ll get answers. :slight_smile:

Thom

3

Hi Thom,

Thanks for the reply.

The setup we have is dedicated point to point, so there are already two wireless cards and antennas at each site, this also enables us to have hi gain directional antennas rather than panels.

The routed solution will be the next step, this will really just optimise the system I think, your are right the bridging is not the best setup for out and out throughput.

Throughput, yes I initially started with the RB BW tester and was suspicious of the RBs not keeping up so I did some more tests with the RB connected via copper on ether1 on each RB, this revealed that the RB BW test is good to around 40Mbps, if I can see this throughput with copper then I should see it with wireless. I have however tried another test which involved copying a massive amount of data across the link and sniffing my NIC, this revealed similar results to the RB BW tester.

Simplicity is basically what I’m going for here, the network needs to be secure but firewalls and the like are not an issue, this is an industrial SCADA network so I’m not too worried about controlling traffic too much, I will hoever have some routing in place so that all the traffic is not bridged out across each link.

The biggest problem I have at the moment however is just getting the RBs to work ptp in the station-bridge mode.

Right I’ll go back to working out what I have done wrong.

4

Mikebarnes -
Well as I remember you’ll have to set the AP Bridge mode on one side - then bridge on the client side. Add whatever you want bridged to a bridge interface that you create, add an IP to the bridge interface only - that should do it… So in your middle stations you would be adding both WLAN interfaces and your ethernet interface to the bridge…

20mbps (TCP) on wireless is about as fast as you are going to go using - non-turbo / bridge and an RB153… It takes a lot of CPU power to move a lot of data wirelessly - the cpu has to fomat the data, there are wait times for the polling mechanisms, etc… An RB 532 will do about 25Mbps on a non-turbo channel, an RB333 will do about 70mbps with nstreme and TCP.

For the time being - if you can - take out any security stuff as well (encryption) so you know the connections are good. You can add security back later.

Even with ‘hi’ CCQ rates you could still be getting interference - what is your channel spacing? What band are you using, etc…

Thom

5

I haven’t gotten into this yet, but I need one AP to bridge between two areas that aren’t capable of a single shot. If WDS is used with 2 radios, is bandwidth still dropped by half?

Not trying to hijack, this is kind of on this topic.

6

Hi 0ldman -
You’re still stuck on that bridging thing aren’t you…
At the 1st WDS link you lose about half, if after that you are using ‘regular’ AP / Station then you don’t lose anymore.

Once again Oldman - just go to a routed solution. If this link you are talking about is new - then this is the time to start. You could have it be routed out there and still come back to your bridged setup… It will be a cleaner easier network to administer.

Thom

7

How is WDS losing 50% of the bandwidth in simple bridging mode? Not used as a repeater, just WDS bridge, dedicated radio for each link. I’ll start another thread about my routing vs bridging.

8

0ldman -
You’re right Oldman - I mistook what you said - since it’s not a repeater - you’ll only lose a little from the WDS overhead ~ 20%

Thom

9

“I have tried to set the links up one as bridge and one as station and the results are not good, I’m getting and asymmetric connection, 54Mbps/6Mbps on the station side, with ccq of 100/75 (have seen 100/34).”

Im not an expert but I think 54/6 is restiricting you to have a reliable amount of bandwidth. Enable nstreme in each site and you will see that 54/6 will change something higher. Also try to adjust the antennas for better shoot or simply change them.

This low conenction rate happened to me aswell in PtP link but solved it with nstreme in turbo-g mode.. Great throuhput..