Running V-REP python remote API on X window terminal (Xterm)

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zubair
Posts: 4
Joined: 18 Sep 2021, 10:00

Running V-REP python remote API on X window terminal (Xterm)

Post by zubair »

Hello Everone,

I have designed a communication Network using Mininet with three hots h1, h2, and h3. I create an xterm on the h3 host and run V-REP client API to connect the server-side application. h3 host ( xterm) running on IP 10.0.0.3 and V-REP using 127.0.0.1. when I use the xterm (X window terminal ) to run the client script it does not connect to the V-REP server side.

However, when I run the V-REP python client script using the Ubuntu terminal or Python IDE (Pycharm) it works fine and connects the server-side (V-REP application).

I'm Using python 3.8 and the V-REP Version(4.1.0) python remote API on Ubuntu 20.04.

coppelia
Site Admin
Posts: 8893
Joined: 14 Dec 2012, 00:25

Re: Running V-REP python remote API on X window terminal (Xterm)

Post by coppelia »

Hello,

not sure what variables mininet introduces. Are you at least able to ping the server side?
You say you are using CoppeliaSim V4.1.0, with CoppeliaSim V4.2.0, you could use the ZeroMQ-based remote API and see if that makes a difference. The ZeroMQ-based remote API is abstracting socket communication to a maximum and giving you much more flexibility.

Cheers

zubair
Posts: 4
Joined: 18 Sep 2021, 10:00

Re: Running V-REP python remote API on X window terminal (Xterm)

Post by zubair »

Hi,
Thank you for your valuable comment. I have attached the results of the client ping to a server in three different terminals. In Python IDE there is also attached a code to ping the server-side which is used for all three experiments.

Python IDE and Ubuntu Terminal works fine and ping the server-side. However, when using xterm it gets ID= -1 and fails to ping.

Python IDE Result: Client ping server-side https://ibb.co/kmk20k6

Ubuntu Terminal Result : Client ping server side https://ibb.co/KGqPBPg

xTerm Result : Client ping server side https://ibb.co/25kXj36

coppelia
Site Admin
Posts: 8893
Joined: 14 Dec 2012, 00:25

Re: Running V-REP python remote API on X window terminal (Xterm)

Post by coppelia »

And what about running following?

Code: Select all

import os
response = os.system("ping -c 1 hostname")
if response == 0:
  print hostname, 'is up!'
else:
  print hostname, 'is down!'
obviously replace hostname with the ip you want to ping.

Cheers

zubair
Posts: 4
Joined: 18 Sep 2021, 10:00

Re: Running V-REP python remote API on X window terminal (Xterm)

Post by zubair »

coppelia wrote:
23 Sep 2021, 08:37
And what about running following?

Code: Select all

import os
response = os.system("ping -c 1 hostname")
if response == 0:
  print hostname, 'is up!'
else:
  print hostname, 'is down!'
obviously replace hostname with the ip you want to ping.

Cheers
I have done the above Experiment and the result in attached as https://ibb.co/fkx2R7C

coppelia
Site Admin
Posts: 8893
Joined: 14 Dec 2012, 00:25

Re: Running V-REP python remote API on X window terminal (Xterm)

Post by coppelia »

Thank you. That is strange. Can you try the ZeroMQ-based remote API, so see if that works?

Cheers

zubair
Posts: 4
Joined: 18 Sep 2021, 10:00

Re: Running V-REP python remote API on X window terminal (Xterm)

Post by zubair »

coppelia wrote:
23 Sep 2021, 15:38
Thank you. That is strange. Can you try the ZeroMQ-based remote API, so see if that works?

Cheers
Thank you so much for your kind response.
I have done the above experiment and the result is attached as https://ibb.co/JjV17x1.
Again it (xterm) does not work however, other experiments works fine.
Its just my imagination that is the Problem https://ibb.co/yYfWc7L.
If i am right. Thee is any way to connect the both mininet (xterm) and V-REP with common IP like NIC.

fferri
Posts: 815
Joined: 09 Sep 2013, 19:28

Re: Running V-REP python remote API on X window terminal (Xterm)

Post by fferri »

So, can you reach the host OS (Ubuntu 20.04) from the guest OS (mininet)?

A first test would be to try with ping or nmap.

If you are unable to ping, it is a network configuration issue between the guest and the host.

Note: previously you showed a test where you would ping 127.0.0.1, but that is the loopback interface, i.e. 127.0.0.1 always refer to the same machine. You cannot reach the host by this IP. You need to find out by which IP the host is reachable by the guest. This information applies to any network, physical or virtual, so it should be the same for mininet, which unfortunately I know nothing about.

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