topic RE: WDS Link Expected TX/RX rate in ExtremeWireless (Identifi)

WDS Link Expected TX/RX rate

Valter_Veiga — Fri, 11 Aug 2017 13:27:00 GMT

Hello,

I have a WDS Wireless Link with 2 AP 3965i-ROW between to building with a distance of 30 Meters.

Setup: Last Firmware V10.31.04.0009

Using 802.3at PoE

Agregation Lan1 and Lan2

Channel 104 : (5500 , [5520], 5540, 5560)

Output: Rx Rss -58

What is the Expected TX/RX rate in this case ?

https://cloud.kapostcontent.net/pub/7dc1aa5b-da46-4460-a96b-f52e3a7dd0a0/ap-3965-data-sheet.pdf?kui=...

RE: WDS Link Expected TX/RX rate

Volker_Kull — Fri, 11 Aug 2017 13:34:00 GMT

On the field without refections and without dedicated antennas (YAGI or sector) you will get not more than 80-100 MBit/s because of using only one stream. I have connections with sector antenna 60° horizontal/vertical 2 streams with 150-200MBit/s on 50m distance.

br
Volker

RE: WDS Link Expected TX/RX rate

Ronald_Dvorak — Fri, 11 Aug 2017 13:41:00 GMT

Could you please post the screenshot from the GUI > Reports > AP > Mesh Statistics.

And what is the problem ?

RE: WDS Link Expected TX/RX rate

Valter_Veiga — Fri, 11 Aug 2017 14:11:00 GMT

Hello,

This is a 3965i, the antenas are integrated 4x4:4, I think is using 4 Stream .....

Volker, the real TX/RX is higher.

RE: WDS Link Expected TX/RX rate

Ronald_Dvorak — Fri, 11 Aug 2017 14:11:00 GMT

what's the value in rx/tx rate ?

RE: WDS Link Expected TX/RX rate

Valter_Veiga — Fri, 11 Aug 2017 14:11:00 GMT

780/780

RE: WDS Link Expected TX/RX rate

Volker_Kull — Fri, 11 Aug 2017 14:15:00 GMT

So what is the real bandwidth you have ? What do you expect ? do you have a problem ? More info is required !
If you use a 4x4 AP with integrated antennas without reflections or dedicated antennas you will not have 4 streams p2p active.

br
Volker

RE: WDS Link Expected TX/RX rate

Valter_Veiga — Tue, 15 Aug 2017 20:03:00 GMT

Why Not 4 streams in WDS Link?

In the datasheet you have, Data Rates MCS0 to MSC9 with Data Streams 1 to 4 and Channel HT20, HT40, HT80.

In the Data Sheet, Maximum Throughput 5GHz Radio 1.732 Gbps and Number of spatial streams 4.

Then you have the Receiver Sensibility.

The picture I send, you have the Rx Rss of -58.

What should be the teorical value of RX/TX ?

In the controller, were can I see the MCS negociated?

VVeiga

RE: WDS Link Expected TX/RX rate

Valter_Veiga — Wed, 16 Aug 2017 00:02:00 GMT

I have run a Lab with this with 2 AP 3965i-ROW , with 5 meters distance.

The RX TX 1560/780 see new upload file.
1560 Means that I has using the PoE 802.3at with 4 Data Streams, and the 780 I was using the PoE 802.3af with 2 Data Streams. Look at Page DataSheet page 7, in normal GI. The Rx Rss was -28

RE: WDS Link Expected TX/RX rate

Volker_Kull — Wed, 16 Aug 2017 12:46:00 GMT

OK, I understand.
You mean the rate the radios negotiate during establishing a connection.
This static parameter does not describe the real bandwidth on the connection.
The internal antennas on 3965i are 360 degrees and prepared for site coverage. If you need 2/4 streams in one direction, you need a directed antenna for that.

Example:
http://www.mars-antennas.com/ma-wa57-qp4mimo19
(19°, 4 Streams 45° MIMO)

So check the real bandwidth wir iperf.

br
Volker

RE: WDS Link Expected TX/RX rate

Gareth_Mitchell — Wed, 16 Aug 2017 13:21:00 GMT

Valter

The rx/tx rate is a moving average of packets rx/tx over the link. MCS is constantly changing depending on what is calculated by a rate selection algorithm, it must choose the best rate based upon the medium quality which, due to the nature of wifi, is not a fixed entity.

As Volker suggested, using iperf over a clean link (without other user traffic) will allow you to get a better baseline.

-Gareth

RE: WDS Link Expected TX/RX rate

Valter_Veiga — Wed, 16 Aug 2017 20:28:00 GMT

I understand,

I'm not looking for real values, I mean the rate the radios negotiate during establishing a connection.

Volker, in your opinion, the AP3965i can work as I see with 4 streams in close distance 5 Meters, but when setup for 30 Meters , only 2 or 3 of the 4 streams can be received by the remote AP ? This is because the internal antena designe location ?

The system mesh report with:
Rx Rss -28 with Rx/Tx 1560 / 780 power 12 dB 5 Meters
Rx Rss -48 with Rx/Tx 877 / 780 power 19 dB 30 Meters
Rx Rss -58 with Rx/Tx 780 / 780 power 12 dB 30 Meters

I was changing the power, from 12 to 19 and the Rx Rss has move from -58 to -48 but the Rx/Tx was not significant.

What is the impact of Rx Rss in the calculated by a rate selection algorithm ?

VVeiga