Re: single radio mesh

[T Gillett]

Hi Luis

Following is what I understand you have in your test set up. 

Would you please confirm or change the details so we can understand and help resolve your issue. 

Also there are included some simple tests that you can run to help isolate the issue.

1. You have three MP2 devices A, B and C which are all loaded with VT SECN firmware.

What version is the firmware?

Each device has both the Mesh and AP wifi interfaces enabled.

No other changes to the default SECN configuration.

The layout of the devices is as follows:

Upstream <-- Ethernet --> Device A  <-- mesh --> Device B <-- mesh --> Device C

                                                               <---------------------- mesh -------------->

2. Device A is connected to an upstream link which has a 20Mbps data bandwidth. The connection is via Ethernet cable connected to the LAN port of the MP2.

3. The three devices are meshed together using a primary wifi channel (ie 1, 6 or 11) which is not used by any other devices in the vicinity.

What channel is used?

4.  The physical distances between the devices are:

A - B  -> ?

B - C  -> ?

A - C  -> ?

5. The Status page for each device shows the batman-adv quality scores for the links of the mesh (0 - 255) in the top frame.

What are the scores?

A screenshot of the Status page from each node will show this.

6. The Status page also shows the signal strength for the links in the third frame.

What are the signal strength SNR values:

A screenshot of the Status page from each node will show this.

7. If you connect a PC to the Ethernet port of Device B, what upstream data rate can you get?

8. If you connect a PC to the Ethernet port of Device C, what upstream data rate can you get?

9. If you connect a PC to the wifi AP of Device A, what upstream data rate can you get?

10. If you connect a PC to the wifi AP of Device B, what upstream data rate can you get?

11. If you connect a PC to the wifi AP of Device C, what upstream data rate can you get?

This information will provide us with an overview of your network and help us to identify any issues.

Regards

Terry

On Sun, Jul 12, 2015 at 6:52 AM, <lmpor...@2uontime.com> wrote:

Hello Steve it's me again I have done the test with three devices and I'm still receiving a loss on the Internet speed I have 20 mbs connection and I'm receiving only 5.2 on my computer via wireless and with a cable directly connected to the device and Im only getting 5.6 I really don't know what the problem could be, I have change the devices and I'm still having the same problem I'm really thinking that the problem is the 3 dbi antenna.
-------- Original Message --------
Subject: Re: single radio mesh

From: "Song, Stephen" <stephe...@gmail.com>
Date: Jul 11, 2015 11:09 AM
To: "lmportillo" <lmpor...@2uontime.com>
CC: "Terry Gillett" <tgil...@gmail.com>,"Chen Edwin" <ed...@dragino.com>

Hi Luis,

You need to give us more concrete data before we can help you.  It is
impossible to say where the problem is at this point.  Can you do a
controlled test with just a couple of devices and replicate the problem?

Regards... Steve

[Luis Portillo]

 

Hello everyone here are the answers of your questions, and sorry for taking so long but I was out of town.

 

ANSWERS:

1.       Yes you are correct, there are no changes on the configuration

2.       Yes

3.       They are connect using Channel 2

4.       Distances are:

A - B  -> 52m

B - C  -> 46m

A - C  -> 49.7m

5.   I’ll send printscreen later

6.   I’ll send printscreen later

7.   6.2

8.   2.7

9.   17.2

10. 5.8

11. 2.6

[T Gillett]

Hi Luis

Thanks for that information.

Can you please tell us the version of firmware that is installed on the device?

You can see this information at the top right of the SECN screen, or in more detail at the splash screen of the command line login.

It is clear that Device A has full access to the upstream link as the wifi connection test in 9. shows, and the links to B and C are greatly reduced as you have noted.

So it is necessary to look at what is happening on the mesh links between the devices.

The information from the Status page will give a good indication about this.
Please send the screen shots when you can.

It is important to see all the information in the first and third fields.

If the information shown is too long to be seen, you can get it from the command line as follows:

For the first field:

    #  batctl  o

For the third field:
    #   iwinfo   wlan0-1   assoclist

Are there any other wifi devices operating in the area, other than just these three test devices? I think you mentioned previously that you have the only wifi devices in the area.

If so, is it possible to ensure that the three test devices are isolated from the wifi signals from these other devices?

 To get wifi isolation, you essentially need to ensure that only three non-overlapping wifi channels are used in the area - channels 1, 6 and 11

For example if your test devices are operating on Channel 11, then all other devices should be using either channel 1 or channel 6.

So you need to check what channels any other devices are operating on, and if possible, move them to one of these three channels such that one of the three channels is left completely unoccupied except for your three devices being tested.

Regards

Terry

[Luis Portillo]

Hello everyone

I have another question does these devices have poe?

 

 

Thank you

 

Luis Portillo

[Song, Stephen]

Hi Luis,

The MP2 Basic and the MP2 Phone do not have built-in PoE support.   Something like the following would work though.

http://www.amazon.com/iCreatin-Passive-Injector-Splitter-Connector/dp/B00NRHNPUA/

Cheers... Steve

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[T Gillett]

Hi All

To illustrate how data rates are affected by various network and mesh parameters, I set up some demonstration tests for monitoring data throughput in a simple test mesh comprised of three MP2 devices (Nodes-A, B and C) set out in a straight line, so that the distance A-C is about double that for A-B and B-C.

The tests use a laptop attached to the LAN port on mesh nodes, and a 100MB file transferred between the laptops using the scp command.

For reference, when the laptops are directed connected using an Ethernet cable, the transfer rate is around 200Mbps.

The operating parameters of the mesh links may be seen in the SECN Status pages of the nodes, and the data rate is shown using the "iftop" command monitoring the bat0 inteface (e.g.  iftop -i bat0 -m 20M ). The end-to-end data rate is also shown in the output of the scp command.

For these tests, the AP was disabled on the nodes.

Test 1
--------

In the first test, Node-A and Node-C are meshed via a single high quality link, with a SNR of 40dB and batman-adv score of 255 as can be seen in the Test-1 screenshots of the Status page of each node.

The transfer rate is up to 30Mbps as can be seen from the Test-1 iftop screenshots.

This test represents a realistic best case scenario for a mesh link using the MP2 devices.

If the link quality decreases for any reason (eg SNR or wifi inteferrence), you can expect that the data rate will be less.

Test 2
-------

In the second test, the data transfer occurs via two mesh hops, A to B and B to C,  with reduced SNR and batman-adv scores for the links, as can be seen from the Test-2 Status screenshots.

The link quality can be adjusted by reducing the TxPower (for all nodes equally) and by extending the distance between nodes.

The end to end data transfer rate for this test is around 10Mbps as can be seen from the Test-2 iftop screenshots.

In the Status screen for Node-B you can see the status of the two active links A-B and B-C.

The Signal Strength section of the Status page also shows the SNR for the link and the number of data packets transferred across the link.

It is worth checking the packet count on each link just to be certain that the data is actually flowing through the link that you expect it to i.e. A-B-C and not A-C.

Looking at the packet counts on the Status pages for Node-A and Node-C should show that one link is carrying the data (A-B or B-C) and the other link (A-C) is idle.

(Of course, if the A-C link is of sufficient quality, data may flow through this single hop rather than via the two hops.)

As a variation on this test, you can move the laptop from Node-C to Node-B and measure the data rate, which will typically be double that for the end-to-end data rate across two links. This is because the MP2 is a single radio device and each additional mesh hop will reduce the throughput by a factor of two.

Hopefully these simple tests will help field testing of mesh network designs.

Regards

Terry

On Thu, Jul 16, 2015 at 4:31 AM, Luis Portillo <lmpor...@2uontime.com> wrote:

[T Gillett]

Some further tests looking at data rates through the AP on the MP2.

Test 3
-------

Test 3 has a laptop connected by Ethernet to the LAN port of the MP2, and a second laptop connected via wifi to the AP on the MP2.

The wifi connected laptop initiates a scp transfer. The iftop screenshot shows the data rate on wlan0, the AP interface on the MP2. 

The System Monitor screenshot shows the network data rate on the second laptop as it is receiving the file.

The data rate is just under 30MBps.

Test 4
-------

Test 4 has two MP2s meshed together, with the first laptop connected to one MP2 via Ethernet, and the second laptop is connected to the second MP2 via wifi.

The second laptop initiates a scp transfer, so the data flows from the first laptop to the first MP2, then across the mesh to the second MP2, then across the wifi link to the second laptop.

The iftop screenshots show the data rate for the bat0 Mesh interface on the first MP2, and the data rate for the wlan0 AP interface on the second MP2.

The System Monitor screenshot shows the network data rate on the second laptop as it is receiving the file.

The end-to-end data rate is around 15Mbps.

These tests were conducted with SNR values of 30 on the Mesh and AP links, and so represent a best case scenario.