UDP port 5001

[guangdew1]

I'm trying to use LabVIEW UDP functions to listen to a device which is SL251 from NetStreams. The following is one of the packets captured by Wireshark. With the information, I think I should be able to use the UDP functions to listen to the port, but I could never establish the connection, it erroed every time. The error code is 54 or something else. I have some concern about this specific port, but it's clearly mentioned by the captured packets. I hope someone can provide some advice regarding the issue. Thanks in advance.

No.     Time        Source                Destination           Protocol Length Info
      4 0.247980    10.15.108.141         239.255.16.90         UDP      70     Source port: commplex-link  Destination port: commplex-link

Frame 4: 70 bytes on wire (560 bits), 70 bytes captured (560 bits)
Ethernet II, Src: Netstrea_02:6c:8d (00:11:61:02:6c:8d), Dst: IPv4mcast_7f:10:5a (01:00:5e:7f:10:5a)
    Destination: IPv4mcast_7f:10:5a (01:00:5e:7f:10:5a)
    Source: Netstrea_02:6c:8d (00:11:61:02:6c:8d)
    Type: IP (0x0800)
Internet Protocol Version 4, Src: 10.15.108.141 (10.15.108.141), Dst: 239.255.16.90 (239.255.16.90)
User Datagram Protocol, Src Port: commplex-link (5001), Dst Port: commplex-link (5001)
    Source port: commplex-link (5001)
    Destination port: commplex-link (5001)
    Length: 36
    Checksum: 0x82c2 [validation disabled]
Data (28 bytes)

0000  51 55 45 45 6c 65 6d 00 10 00 20 00 96 c2 ce 80   QUEElem... .....
0010  8d 6c 02 61 0a 0f 6c 8d 9f 72 33 bb               .l.a..l..r3.

[Matt_McLaughlin]

Hi guangdew1,

Have you used this LabVIEW VI successfully in the past? Could you post the code or a screenshot of it to confirm that things are configured correctly? This error typically indicates that the network address input is not configured correctly, so having a look at how things are configured will be helpful. At what point in the code is the error being thrown.

It will also be worthwhile to confirm that a firewall is not interfering with the communication.

[altenbach]

UDP is connectionless, so the term "establishing a connection" is confusing. You are just passively listening for packets. If a packet arrives, parse the payload and handle it (display, process, etc.), if not, keep listening.

Note that the destination address is a designated multicast address  (224.0.0.0 to 239.255.255.255) that all local computers will receive, so these packets are multicast. (Don't ever configure your computer with IP address 239.255.16.90!!)

LabVIEW has special multicast tools in the UDP palette, so they might be more suitable. Try UDP multicast open.

[guangdew1]

Hi Altenback,

Thank you for your help.

I tried both UDP Open.vi and UDP Multicast Open.vi, none of them worked. The term "connection" is confusing here, I know it's connectionless, but the two Open.vis also used the term "connection ID" after the open. What I mean is that if I use the port 5001, then it will get errored during open. Using some other port numbers may pass the open without an error, but couldn't read anything. Right now, the only thing I have read from the device is the DHCP message from port 68. I'm trying to send some commands to the device from port 67, but I don't see any response from the device.

Best regards,

[guangdew1]

Hi Matt,

Thank you for your help.

There are not many vis on the UDP pallet, what I used is just an UDP Open.vi (or UDP Multicast Open.vi), an UDP Read.vi and and UDP Close.vi. I do have a question here, that is, whether we can use UDP Open.vi to read a multicast instead of using UDP Multicast Open.vi, or vise versa.

Best regards,

[altenbach]

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@guangdew1 wrote:

I tried both UDP Open.vi and UDP Multicast Open.vi, none of them worked. The term "connection" is confusing here, I know it's connectionless, but the two Open.vis also used the term "connection ID" after the open. What I mean is that if I use the port 5001, then it will get errored during open. Using some other port numbers may pass the open without an error, but couldn't read anything. Right now, the only thing I have read from the device is the DHCP message from port 68. I'm trying to send some commands to the device from port 67, but I don't see any response from the device.

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If you get an error opening server port 5001, it most likely means that the port is already in use. Can you at least tell us the error message and number?

What kind of commands are you trying to send to the device? What kind of response is the device supposed to send back?

What do you mean by "from port 67". Does the device except a certain source port?

You are randomly mixing talking about outging, incoming, plain UDP, multicasts, and broadcast messages. Who is the server and who is the client? What port is the device listening on if it is the server? What port are you expecting device messages (if it is the client)?

All we have so far are random ramblings that make very little sense. Is there an online manual that describes how to communicate with the device and the format of the messages?

[lucmazavason]

Hello! For me, I have seen this error. How to resolve it please?

My computer system is 64bits, and, I have installed the LabVIEW 2012 32bits.

Thanks for your help!

[billko]

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@lucmazavason wrote:

Hello! For me, I have seen this error. How to resolve it please?

My computer system is 64bits, and, I have installed the LabVIEW 2012 32bits.

Thanks for your help!

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Start your own thread.  This has nothing to do with the original subject.