IP without TCP

[Nepomuk]

hi,

i need to communicate with an external device (not a PC, but with an ethernet connector). The manual only tells me the instructions i can send, but they dont mention any Protocol or, in case of TCP, a port. I programmed a Labview-program with the TCP/IP functions, which works well between different PCs, but not with my external device ( I only have an IP-number)

Could it be, that my device only uses the IP-Protocol and how can I program a IP-connection in Labview. All i found are TCP/IP or UDP/IP Connections.

Thanks a lot for everyones help

Andy

[LAVA 1.0 Content]

In general, LabVIEW network communications is going to via TCP or UDP. There are higher level protocols such as Data Socket (DSTP) and HTTP that can be used if the device supports these.

Tell us about your device or share the manual and someone might be able to help.

[jdunham]

QUOTE(Nepomuk @ Jan 31 2008, 02:23 PM)

Could it be, that my device only uses the IP-Protocol and how can I program a IP-connection in Labview. All i found are TCP/IP or UDP/IP Connections.

I don't think so. You might want to read up on the http://en.wikipedia.org/wiki/OSI_model' target="_blank">OSI model. IP is at layer 3, which is a network layer. As it shows in the chart (follow the wikipedia link), it shouldn't be possible for two hosts to share data without using one of the host data layers (layers 5, 6, or 7). For example, your ethernet cable itself is layer 1, but just because your machines are connected at layer 1, doesn't mean you can transmit any data without some implementation of layers 2, 3, 4 and 5 as well.

If the other machine you are connected to has no specifications for layer 4 and 5, you are going to have to get that information from that machine's vendor.

Have you tried to enter the device's IP address in a web browser? lots of small devices implement help and configuration by implementing a small web server on the device. Can you ping the device?

There are also tools like nmap which can scan for open ports, though a phone call to the vendor would be a lot faster.

[LAVA 1.0 Content]

I beleive it used to be possible to run DECnet over IP so I am inclined to think that IP supports this. But from what I understand about the Windows implementation fo the OSI 7-layer model, both TCP and IP are implemented together.

All of the above is just my opinion and is possibly (probably) wrong.

Ben

[jdunham]

QUOTE(neB @ Feb 1 2008, 10:17 AM)

I beleive it used to be possible to run DECnet over IP so I am inclined to think that IP supports this. But from what I understand about the Windows implementation fo the OSI 7-layer model, both TCP and IP are implemented together.

All of the above is just my opinion and is possibly (probably) wrong.

Ben

Well you are probably right, but just because DECnet may not have used TCP or UDP doesn't mean it didn't implment some of layer 5. Even if they rolled something proprietary, the point of the OSI Model is that whatever knows about the data is classified as layer 5 and above and you are not going to be able to get access to the data without vendor documentation or an open standard on how they implemented layer 5.

[LAVA 1.0 Content]

QUOTE(jdunham @ Feb 1 2008, 01:29 PM)

Well you are probably right, but just because DECnet may not have used TCP or UDP doesn't mean it didn't implment some of layer 5. Even if they rolled something proprietary, the point of the OSI Model is that whatever knows about the data is classified as layer 5 and above and you are not going to be able to get access to the data without vendor documentation or an open standard on how they implemented layer 5.

Agreed.

At least under VMS version 4 DEC did implement the entire stack as defined by the OSI-7-layer model. THe only reason I know this is that I had access to the VMS source code while I was working for them.

Ben

[Mellroth]

QUOTE(Nepomuk @ Jan 31 2008, 11:23 PM)

i need to communicate with an external device (not a PC, but with an ethernet connector). The manual only tells me the instructions i can send, but they dont mention any Protocol or, in case of TCP, a port.

Hi Andy,

First some questions:

Can you tell us what kind of device you are trying to use?

You say the manual list a set of commands you can send, could you please give an example of a command?

Does the manual say anything about how you should end a command, e.g. LF, CR etc.? If it does it is probably a stream connection ala TCP/IP, TELNET, ...

Do you only have the IP address, no additional IP port information? (If no port is given, I would think that there is a standard protocol in use)

Then some comments:

As jdunham said, use a port scan to see what ports are open, then check the ports against a list of known ports ( http://www.networksorcery.com/enp/protocol/ip/ports00000.htm ).

To check the communication, you could download a free network analyzer called Wireshark ( http://www.wireshark.org/ ). Off course this only works when sniffing on a established connection.

Good luck

/J

[Nepomuk]

hi to all,

thanks for all of your answers. After trying more and more I decided to give the manufactorer a call and they told me, that they have more documents about it

So the connection is a UDP/IP and the ports are already defined. Now I think it shouldnt be a problem (hopefully) to implement this.