how to realize a ping

[paololt]

Hi all, i need someone help me

I have to realize a ping between two pc; i'm following an example i found in Labview example under the section udp networking.

My problem is that: i have 2 strings to compare bit by bit: data sent and data received and then i have to calcolate bit error rate.

how i can do that?

thank you

[Justin Goeres]

QUOTE(paololt @ Nov 17 2007, 03:25 AM)

Hi all, i need someone help me

I have to realize a ping between two pc; i'm following an example i found in Labview example under the section udp networking.

My problem is that: i have 2 strings to compare bit by bit: data sent and data received and then i have to calcolate bit error rate.

how i can do that?

What have you done so far and where are you stuck? If you can post some of your code we can probably point you in the right direction.

[paololt]

QUOTE(Justin Goeres @ Nov 17 2007, 04:01 PM)

What have you done so far and where are you stuck? If you can post some of your code we can probably point you in the right direction.

ok..i have realized the comunication between two pc; i send a string from one of them and i receive the same string. Now i have to compare the two stings bit by bit abd then i have to find if there are errors or not. But i can't do that. i'm looking for a function to compare the two strings but i don t find it. I suppose i can convert stings to byte array and then compare the 2 byte arrays bit by bit but i can' t do that at all. can you help me please?

thank you

[Justin Goeres]

QUOTE(paololt @ Nov 17 2007, 10:09 AM)

ok..i have realized the comunication between two pc; i send a string from one of them and i receive the same string. Now i have to compare the two stings bit by bit abd then i have to find if there are errors or not. But i can't do that. i'm looking for a function to compare the two strings but i don t find it. I suppose i can convert stings to byte array and then compare the 2 byte arrays bit by bit but i can' t do that at all. can you help me please?

You're on the right track, and there are a lot of different ways you can solve the problem.

Here's a pretty straightforward way. Everything you see here is in your Boolean, String, and Numeric palettes.

http://lavag.org/old_files/monthly_11_2007/post-2992-1195320875.png' target="_blank">

[paololt]

QUOTE(Justin Goeres @ Nov 17 2007, 06:37 PM)

You're on the right track, and there are a lot of different ways you can solve the problem.

Here's a pretty straightforward way. Everything you see here is in your Boolean, String, and Numeric palettes.

http://lavag.org/old_files/monthly_11_2007/post-2992-1195320875.png' target="_blank">

Thank you very much for your help..now i try to do that.

another question please. i have to put my results in a graph. i explain you better. i have to graph the bit error rate in function of the dimension of the packet.

with your help i can obtain bit error every time, but now how can i put this resuolta in a graph to have ber?

thank you again

[Götz Becker]

QUOTE(paololt @ Nov 17 2007, 06:09 PM)

ok..i have realized the comunication between two pc; i send a string from one of them and i receive the same string.

Hi,

out of curiosity, how do you communicate between your PCs?

ICMP, TCP or UDP and what kind of link layer is involved in your setup? I am just wondering if you can find any biterrors using standard hardware. As I recall correctly, there might be several CRC-checks present (TCP for sure and I guess Ethernet frames too) when using standard hw and network stacks.

[psi]

A good example for communication between computers is publish subscriber of Eugen Graf. The latest version publish subscriber you can find on the russian forum PubSub.

This program use four types communication Queue, Notifier, User Event, TCP/IP and in TCP/IP protocol use SyncBytes and Checksum.

[Eugen Graf]

QUOTE(psi @ Nov 18 2007, 11:00 PM)

A good example for communication between computers is publish subscriber of Eugen Graf. The latest version publish subscriber you can find on the russian forum PubSub.

This program use four types communication Queue, Notifier, User Event, TCP/IP and in TCP/IP protocol use SyncBytes and Checksum.

Thank you PSI, but I removed SyncByte and Checksum from my TCP/IP package Wrapper in the last latest version of Pub/Sub, because I got the inormation, that TCP/IP protocol GARANTEES the incomming of packagees to the receiver, otherwise you will get an error from TCPRead.vi , so you don't need to recheck the package and make some more TCP traffic.

Eugen Graf

[Rolf Kalbermatter]

QUOTE(paololt @ Nov 17 2007, 05:25 AM)

Hi all, i need someone help me

I have to realize a ping between two pc; i'm following an example i found in Labview example under the section udp networking.

My problem is that: i have 2 strings to compare bit by bit: data sent and data received and then i have to calcolate bit error rate.

how i can do that?

thank you

First your use of the word ping could be a little misleading here. It usually means a specific network procedure that is passing small packages using the ICMP protocol. ICMP is one of the more low level protocols directly above the IP package layer and there are no VIs to access that directly in LabVIEW.

From what I see you are using UDP instead to do some bit error calculations. I'm not sure what you are trying to do by this but if it is about classifying hardware failures for instance in the network cards or network infrastructure your attempt is flawed greatly. UDP while connectionless and not guaranteeing data delivery is also based on the IP protocol and as such has already gone through some IP checksum and such too. So you won't really get much information about the involved hardware failure rate, but at best some indication about the ability of your network topology to cope with the amount of data you throw at it. For small buffers and not being on a congested corporate network this should be very close to 100%.

Rolf Kalbermatter