UDP Multicast

I am trying to send a message between to computers on a network using Multicast UDP. I receive no errors, but the message does not get to the receiver. I was able to get a regular UDP message between them, but not a multicast. I have the address set to a valid multicast address and I have the TTL set to higher than the number of hops. What could I be missing?

Well, I've got the same problem. Unfortunately, I must use multicast.
I am using the multicast send example VI on one PC, and the multicast receive example VI on another. The 2 PCs are directly connected with an Ethernet cable. Wireshark running on the receive PC sees the multicast UDP packets, but the receive VI does not. If I also run the send example on the receive PC, then all of a sudden the receive VI gets both the multicast packets from both senders.
I have turned the firewall off on both machines. One machine is XP, the other is Windows 7. Any ideas?
Similar experiments with Java do not exhibit this strange behavior.

Similar Messages

Problem with receiving of the UDP multicasting on multiple interfaces in the W2K12 cluster

Hi,
I have my .NET application which receives the UDP multicasting communication. It works fine until it is deployed on a W2K12 cluster. Some multicast groups are still available and some are not in the cluster. The
problem is caused by the cluster which creates a virtual interface for a inter-node communication. When the cluster is on and my app is trying to subscibe to the affected group then IGMP packets are routed to the cluster's
virtual interface where the multicast communication is not available. When the cluster (cluster service) is off all groups are available and IGMP is routed to a right interface.
I also have a different application which is not based on .NET and it receives all multicast groups in any deployment (same W2K12 clustered server). So, I guess that in my app I have to tell to the socket somehow, which local interface should
be used for a particular multicast group. In my app I use code below for a group subscribtion, but I still can't manage routing of IGMP to a right local interface. Can you help me?
As you can see in the code example I try to mapp a group to a local interface using its IP and index using MulticastOption class, but it has no effect. Different interface (cluster's virtual interface) is used for a IGMP
subscribtion. I also tried to bind\set local interface to Any, but without success.
It seems that there is some OS logic which overrides my setup. But, it must be possible to do the socket setup correctlly because non .NET application works fine.
Thanks.
Regards,
Marek
public void Start(string[] args)
//args[0] - multicast group
//args[1] - multicast port
//args[2] - local interface IP
//args[3] - local interface index
UdpClient udp = new UdpClient();
udp.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
udp.Client.Bind(new IPEndPoint(IPAddress.Parse(args[2]), Convert.ToInt32(args[1])));
MulticastOption mcastOption = new MulticastOption(IPAddress.Parse(args[0]));
mcastOption.LocalAddress = IPAddress.Parse(args[2]);
mcastOption.InterfaceIndex = int.Parse(args[3]);
udp.Client.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, mcastOption);
udp.BeginReceive(new AsyncCallback(Receive), udp);

I don’t know if it will help you but I can illustrate my problem on the following prints from netsh and route tools. First print from netsh shows that the affected group 224.0.46.232 is assigned to interface 20. Second print shows
that interface 20 is Microsoft Failover Cluster Virtual Adapter where multicast communication is not available.
When the test app, which works fine, is used than these prints show that group 224.0.46.232 is assigned to interface 19 - Microsoft Network Adapter Multiplexor Driver, where multicast communication is available.
So, the question is how to manage these „prints“ to requested setup in .NET.
Regards,
Marek
C:\Windows\system32>netsh interface ip show joins
Interface 1: Loopback Pseudo-Interface 1
Scope       References Last Address
0                    0 Yes   239.255.255.250
Interface 20: Local Area Connection* 12
Scope       References Last Address
0                    0 Yes   224.0.0.1
0                    1 Yes   224.0.0.252
0                    1 Yes   224.0.46.232
Interface 19: Public
Scope       References Last Address
0                    0 No    224.0.0.1
0                    1 No    224.0.0.252
0                    0 Yes   239.255.255.250
C:\Windows\system32>route print
===========================================================================
Interface List
19...3c d9 2b ef 8a ec ......Microsoft Network Adapter Multiplexor Driver
20...02 91 08 09 1a ae ......Microsoft Failover Cluster Virtual Adapter
1...........................Software Loopback Interface 1
16...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter
21...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #3
===========================================================================

I have to send messages through UDP multicast and unicast from same port. In Labview I tried that it throws error. I heard it is possible by means of Datagram (UDP unicast and multicast) Port Sharing. How can it be achieved in Labview?

I have to send UDP multicast and Unicast messages to a remote port from a single source/local port. I tried by opening UDP unicast and multicast in the same port and got the expected error. I tried by opening a unicast connection and sending unicast messages.After that when multicast messages has to send I closed unicast and opened multicast in the same port.This is not throwing any error. But my requirenment is to comminicate with another application in C ++ which recieves this data, throwing an error of lost connectivity and both the applications are not abled to communicate properly.
In the other application with C++ this is implemented using port sharing. So how port sharing can be implemented in labview so that I can send both multicast and unicast messages from the same port?
Thanks in advance

UDP is a sessionless protocol, meaning that anyone listening on the specified port CAN receive the data. CAN because as you noted there is no guarantee in the protocol that it will be received. And if you send the data not to a specific address but a multicast address not only one computer can receive it but in fact every computer on the same subnet listening to that multicast address and depending on the TTL of the packet also computers in neighbouring subnets, although that last one is not a very reliable operation since routers can be configured to drop multicast packages anyhow despite of a different TTL saying otherwise.
Accordingly there is no real way to make sure that a receiving UDP port is not already in use, since you don't build up a connection. UDP is more or less analogous to shouting your messages through a megaphone, and anyone listening on the right frequency (port) can hear it. You do bind the sender socket to a specific port number but that makes little difference.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

WRT54GS slow UDP multicast speed

Hi everyone. A techie question for you! I am having problems using UDP multicast/broadcast over UDP. My PC is wirelessly connected to our LinkSys WRT54GS router. I have a small application that broadcasts data over UDP. When I send data using unicast (to a specific IP address) the router is reasonably fast, over 2mbps. But when I send data using multicast or broadcast modes over UDP, it is really slow, like about 100kbps. When I connect to the router with an ethernet cable, it runs multicast very fast. When I connect to another router (a D-Link) it also runs multicast very fast. I have the "Filter Multicast" option unticked on the firewall page. Any ideas about why it is running so slow? Thanks! Matthew.

Hi,
I'm also having trouble with milticast traffic on WRT54G2.
My linux milticast router (igmpproxy) is connected to the internet on one side and to local network on the other site. On one LAN site, there is a WRT54G2 acces point / switch.
If I watch IPTV on the LAN, the WLAN is extreamly slow to the point being unusable.
Is there a solution to this problem?
Similar problems:
http://forums.linksysbycisco.com/linksys/board/message?board.id=Wireless_Routers&message.id=118765
http://forums.linksysbycisco.com/linksys/board/message?board.id=Wireless_Routers&message.id=73514

UDP MultiCast on cFP

I am attemtping to write an application for the cFp 2120 that uses UDP multicast. I developed it mostly on my PC and was surprised to find it not supported on cFP once I downloaded it for the first time. I have searched for information on this and can't find much. I found in one post that the I should use UDP Broadcst instead of multicast but there is no UDP Broadcast vi. Is the standard UDP read and write whatthey are refering to? Is this truely not available?
Thank you for your help.

Hi GeneHancock,
UPD is supported on cFP. It is lossy. There are other methods of communication detailed here. Can you clarify what you mean by unsupported? Did you install all the drivers onto your FieldPoint as well?
Regards,
Hillary E
National Instruments

Is UDP Multicast support in LV RT 8.6?

Is UDP Multicast supported in LabVIEW Real-Time 8.6?

No, this is definitely not "normal", it's an unfortunate example of mis-tagging the example VIs. VIs are tagged in a number of different ways in the example finder, the ones you mostly see are:
1. Written specifically for RT
2. Written specifically for LabVIEW (Host)
3. Written for LabVIEW but could still work on RT.
The multicast examples were tagged with the "Written for LabVIEW but could still work on RT" when they should have been tagged, "Written specifically for LabVIEW (Host)." We apologize for any confusion, we'll try to make sure this is fixed in the next release of LabVIEW.
-Danny

UDP multicast subscriber for RT using CVI 8.5

Does anyone know of a way to implement a UDP multicast subscriber on an RT system using CVI 8.5? I know that CVI 2009 supports UDPMulticastSubscribe/UDPMulticastUnsubscribe functions, but I'd rather not upgrade if I can avoid it.
Can this be done using the Windows SDK? Is it even possible?
--NDo
Solved!
Go to Solution.

The reason that the CVI library multicast functions weren't supported until version 2009 is that the underlying Windows SDK implementation provided by LabVIEW Real-Time did not support UDP multicast. This means that unless you have LabVIEW Real-Time 2009 on the system, multicast is impossible. It might be possible to install LVRT 2009 and use the Windows SDK directly, without upgrading to CVI RT 2009. I have not tried this, though, so I can't guarantee you won't run into problems.
Mert A.
National Instruments

UDP/Multicast Broadcasts

Hello,
I am interested in writing some P2P-ish type networking
applications which need to use UDP multicasting to discover other
participating hosts on the network. Does AS3 networking libraries
have the ability to do UDP and multicasting?
Thanks,
Brad

If you want the UDP connection to have multiple listeners:
- Open the file: LabVIEW.ini (it is most likely located in C:\Program Files\National Instruments\LabVIEW 7.x, where "x" is the version number.)
- Add the line: SocketSetReuseAddr=TRUE
- Restart LabVIEW. The changes should take effect.
If you do not want to have multiple listeners, but want to be able to have multiple writers to the same port, this does not apply. You can open different local ports so as not to generate Error 60 and then write to the same remote port without causing an error.
If you are trying to communicate with multiple devices using the LabVIEW UDP VIs where each device has a unique IP addresses that are both listening on the same port in parallel, you can do the following:
This error occurs because you cannot open multiple connections on the same local port. However, the local port and the remote port do not need to be the same. The local port is determined by the "port" inputs of the UDP Open VIs. The remote port is determined by the "port" inputs of the UDP Write VIs. For each write, set the remote port to the one on which the corresponding device is listening.
I would also recommend that you look at the following link:
http://zone.ni.com/devzone/conceptd.nsf/webmain/BB41313D7AB28CBD86256802007B8DC5?opendocument
Nandini Subramaniam
Applications Engineer
National Instruments

ASA 5585X in L2 trans. mode drops (ASP) fragm. IPv4 UDP multicast

Hello Community,
it seems there are problems with dropped fragmented IPv4 UDP Multicast traffice on an ASA 5585X platform running ver. 8.4(6)5. The following sample topology has been used for the verification scenario:
MC src and rcv
(XChariot)
|
-----C4503---------------ASA5585X-L2mode-----------IPSEC-Appl.------WAN----------Remote Site with (S,G) (10.10.4.156,225.1.2.154) (XChariot)
|
MC src and rcv
(XChariot)
Test 1 (S,G) (10.10.4.156,225.1.2.154) sends UDP with a UDP length of 1341
(Trace "WAN-IF_capture_225.1.2.154_no-frag" and
output "L2FW-not_fragmented"
The traffic passes through the Transparent mode ASA without any problems.
Test2 (S,G) (10.10.4.156,225.1.2.154) sends UDP with a UDP length of 3441 resulting in fragmentation.
This traffic and unfortunately it is the same for the real application is drop by the ASA. The two ASP drops counters for "
Dst MAC L2 Lookup Failed" and "invalid-udp-length" are increasing in a realtion of 3(DstMAC):1(invalid udp).
The file"L2FW-frag_IPv4_UDP_MC_ASPdrops" shows first the capture on the WAN and then the captures on the ASP drops. In addition the three traces in pcap format.
Any idea?
Thank you in advance for you contribution.

Hello Community,
the following combination solved our problem for now, upgrade to ASA OS 9.1.3 (asa913-2-smp-k8.bin) and the change from virtual reassembly (default) to hardware reassembly -> global-cfg -> fragment reassembly full [interface].
http://www.cisco.com/en/US/docs/security/asa/command-reference/f2.html#wp2019322
Perhaps further test will be made with using lower interim versions.

What is the difference between "UDP Multicast open.vi " and "UDP open.vi " ?

What is the difference between "UDP Multicast open.vi " and "UDP open.vi " ?

Someone correct me if i am wrong, the difference is "multicast"
-Based on my General Computer Network knowledge, multicast means sending data/packets to selected group of nodes. Which will be UDP multicast
-UDP open.vi might be for unicast which is to one node specifically.
-One more difference is in first one(multicast open), you have additional read,write and read write funcionality which is not available in normal UDP open.vi
Thanks
uday,
Please Mark the solution as accepted if your problem is solved and help author by clicking on kudoes
Certified LabVIEW Associate Developer (CLAD) Using LV13

Using UDP broadcast instead of UDP multicast on a LAN (multicast not working on a major UK ISP router)

I've built an Android app using Cirrus that allows users on a LAN to chat in Morse code! - You can find it on the Android Market by searching for 'Morse Intercom'.
It works fine on my network, lots of other networks, but not on probably the most popular fast broadband fibre network in the UK
A friend of mine has let me piggyback on her network from this provider, and the problem appears to be that the UDP multicast packets RTMFP transmits just aren't being put on the wireless network. FYI the multicast address I use is IP 225.226.227.1 port 32112 .
This is probably fixable in the router, but 99.5% of users will never mess around with the router (and why should they), and if possible I would like to fix this in RTMFP.
Is it possible for me to ask RTMFP to not use UDP multicast, but instead to use UDB broadcast for discovering peers on the LAN ? The problematical router (and all others?) supports UDP broadcasting.
I tried setting 'groupspec.ipMulticastMemberUpdatesEnabled = false;' but this just stopped the app working on anything! What is the purpose of this option?
FYI:
To connect without using Cirrus server assistance I use: nc.connect("rtmfp:");
The complete function I use for setting up multicasting is:
private function setupGroup():void
// Create a new Group Specifier object
//trace("setUpGroup: groupSpec = new GroupSpecifier('myGroup/groupA')");
trace("setUpGroup: groupSpec = new GroupSpecifier('" + MY_UNIQUE_GROUP_NAME + "')");
var groupspec:GroupSpecifier = new GroupSpecifier(MY_UNIQUE_GROUP_NAME);
// Enable posting
trace("setUpGroup: groupspec.postingEnabled = true");
groupspec.postingEnabled = true;
// Specifies whether information about group membership can be exchanged on IP multicast sockets
trace("setUpGroup: groupspec.ipMulticastMemberUpdatesEnabled = true");
groupspec.ipMulticastMemberUpdatesEnabled = true;
// Causes the associated NetStream or NetGroup to join the specified IP multicast group and listen to the specified UDP port.
//trace("setUpGroup: groupspec.addIPMulticastAddress('225.225.0.1:30000')");
trace("setUpGroup: groupspec.addIPMulticastAddress('" + MY_MULTICAST_ADDRESS + "')");
groupspec.addIPMulticastAddress(MY_MULTICAST_ADDRESS);
// Constructs a NetGroup on the specified NetConnection object and joins it to the group specified by groupspec.
trace("setUpGroup: group = new NetGroup(nc,groupspec.groupspecWithAuthorizations())");
group = new NetGroup(nc,groupspec.groupspecWithAuthorizations());
// Set the NET_STATUS event listener
trace("setUpGroup: group.addEventListener(NetStatusEvent.NET_STATUS,netStatus)");
group.addEventListener(NetStatusEvent.NET_STATUS,netStatus);
In conclusion - On a LAN with up to 250 or so hosts, I can't see why RTMFP shouldn't be able to use UDP broadcasting as an alternative to UDP Multicasting. Can it, and if so how?
Graham

Here's more information...
When trying to connect with a 3rd party product, the connection request is sent out to my ISP's DNS server with details of the service ID. Of course it won't find anything there.
So then is tries to use NBNS (Netbios Naming Service) on 192.168.1.255, and still can't connect. Then comes back with a TNS error. i tried TNSPING on this address, and it doesn't find it. I have no clue where it gets this address from.
WHY WON'T IT JUST CONNECT TO THE HOST MACHINE AS DEFINED IN THE TNSNAMES FILE???
PLEASE HELP!!!!

Error 54 on udp multicast cRIO

I'm trying to get a cRIO-9075 broadcasting data over a network with UDP. I've opened the UDP multicast examples and they work fine when I run them on my development computer. When I deploy and run the examples on the cRIO controller however, I get either 'Error 54 - the network address is ill-formed' if trying to use the send/recieve example or run UDP open in read/write mode, or "Error 59 - the network is down, unreachable or has been reset" if i try to use just UDP send or UDP open in write only mode.
I'm using a valid multicast IP address that is within the multicast region (234.5.6.7 as in the example), have tried multiple ports, (0, 58432, 50001...) and have tried with my firewalls disabled, wireless internet connection and bluetooth all disabled. The cRIO is connected directly to the development PC via a straight network cable, although I'm pretty sure my network card is sorting out the crossover detection as everything else on the connection is working fine.
Does anyone have any ideas on how to debug this? I've kinda hit a brick wall here, so any help would be greatly appreciated.
Solved!
Go to Solution.

Hi Aidan,
What you said was correct, however it seems that after trying again this time I've had success transferring data. I'd doubt my code, and will be sure to post snippets next time, but as my post says I ran the labview UDP multicast example pair on the development machine, so I can only suppose a network hitch... Very strange, as sending data over the same socket with the TCP/IP example worked.
Since then things seem to be going mostly smoothly - I've been able to broadcast data from the cRIO and pick it up on the development PC. I have hit a bit of a hitch with sending datagrams of 8192 bytes ...
Spoiler (Highlight to read)
I'm getting 'error 113 - the datagram is too large for the buffer or other network limit' on the UDP recieve end. I believe 8192B is the maximum UDP packet size, and don't get any errors on write, but even increasing the socket buffer size by modifying the windows dll as per here (http://digital.ni.com/public.nsf/allkb/D5AC7E8AE545322D8625730100604F2D) I'm still receiving the error. Using smaller packet sizes (e.g 540B) seems to work, but as I'm trying to maximise throughput it could pose an additional limitation. I've read 64MB is the UDP protocol maximum size, and 8192B is a labview limitation. Any ideas on this?
I'm getting 'error 113 - the datagram is too large for the buffer or other network limit' on the UDP recieve end. I believe 8192B is the maximum UDP packet size, and don't get any errors on write, but even increasing the socket buffer size by modifying the windows dll as per here (http://digital.ni.com/public.nsf/allkb/D5AC7E8AE545322D8625730100604F2D) I'm still receiving the error. Using smaller packet sizes (e.g 540B) seems to work, but as I'm trying to maximise throughput it could pose an additional limitation. I've read 64MB is the UDP protocol maximum size, and 8192B is a labview limitation. Any ideas on this?
...but I suppose that's another issue.
For now I think I'll leave the cRIO on a static IP and not get hung up on this issue. Thanks for working through this with me Aidan.
For the record: the port was 58432, multicast address 234.5.6.7 as in the UDP multicast examples. development PC was XP, 2.26GHz dual core w/ 3GB RAM (limited as 32-bit), will update with ethernet card later as I'm on a different machine right now.

LV2011 udp multicast open error 54

Hi guys,
I'm working on conversion from LV8.6 to 2011 for one of my projects. One thing I found was that the UDP broadcast module no longer worked. After digging into the vi i found that the "UDP Multicast Read-Write Open.vi" did not work the way as in 8.6.
I used a net address string input of "172.16.1.234" (my secondary network card), after string-to-ip conversion it gave 2886730218. then the UDP vi gave an error 54 in LV2011. (in 8.6 this does not happen)
I even tried using 127.0.0.1 or with ONLY my primary network card enabled (172.22.1.100), it always gives error 54.
The only input to make it pass i found was 0.
I have attached a ss of my test vi. Thanks for your inputs.
LabVIEW 2011 newbie >.<
Certified LabVIEW Developer
Solved!
Go to Solution.

Thanks for the reply. I have also checked that example. Please note that in the example it doesn't have an input for the net address, which i assume labview 2011 will use 0.
I have also just received a reply from NI and confirmed it's a known bug in 2011. i will post it below.
I hope this finds you doing well. I am glad to hear that you are starting to upgrade to 2011 and I apologize for the issues you are seeing. I suspect you are using this on one of our Real-Time targets if so the good news is that this behavior has been documented in the form of a CAR (actually a
few): Broadcasts and the UDP Open VI have an INCONSISTANT behavior depending on the OS. Pharlap/Windows receive broadcasts when the "net address" terminal is wired while vxWorks/Linux don't. These CARs are scheduled as major incoviencience and will be fixed in a future version of LabVIEW as of now the work around is to simple not wire the net address field.
The CAR numbers incase you would like to see when they are fixed are:
257627, 233344,235444, 283205
LabVIEW 2011 newbie >.<
Certified LabVIEW Developer

WES7 UDP Multicast Open problem

Hi
I am using LabVIEW 2012 SP1 programming a TPC-2206 touch-panel computer running Windows Embedded Standard 7.
I have a fairly simple program which uses the LabVIEW "UDP Multicast Open" VI to open a Read-Only multicast port, then reads data continously from it using the "UDP Read" VI.
The routine works by calling the "UDP Multicast Open" VI and if successful, then entering a continous While-loop which reads from the opened port via the opened Connection-ID refnum. If unsuccessful at opening, the routine sits there waiting for the Open to succeed, displaying a message to the user that the network is not plugged in (or similar).
My problem is that if I open the port without a network connection, the open operation succeeds (which is great as its a multicast open and that seems like the right thing it should do), but subsequently when I plug in the network with good data being sent on it, I do not receive anything?! I would have expected data to be received if the port succeeded in opening, no matter what the initial condition of the connection.
When I tried this on Windows XP, I got a open failure which let me know the network was not plugged in. I subsequently programmed it to put up the flashing message and waited for a good connection such that "UDP Multicast Open" then succeeded. Subsequent reception was then good.
Is this a known difference between WES7 and WinXP and LabVIEW "UDP Multicast Open"/"UDP Read", or am I missing something?
Thanks for any help you can give.

Thanks for the reply. I have also checked that example. Please note that in the example it doesn't have an input for the net address, which i assume labview 2011 will use 0.
I have also just received a reply from NI and confirmed it's a known bug in 2011. i will post it below.
I hope this finds you doing well. I am glad to hear that you are starting to upgrade to 2011 and I apologize for the issues you are seeing. I suspect you are using this on one of our Real-Time targets if so the good news is that this behavior has been documented in the form of a CAR (actually a
few): Broadcasts and the UDP Open VI have an INCONSISTANT behavior depending on the OS. Pharlap/Windows receive broadcasts when the "net address" terminal is wired while vxWorks/Linux don't. These CARs are scheduled as major incoviencience and will be fixed in a future version of LabVIEW as of now the work around is to simple not wire the net address field.
The CAR numbers incase you would like to see when they are fixed are:
257627, 233344,235444, 283205
LabVIEW 2011 newbie >.<
Certified LabVIEW Developer

RTP (UDP) multicast stream with JMF...?!

Hi.
I am quiet new in the material of jmf and its plugins. I have a network which offers me an UDP stream (mpeg2 or mpeg4 both could be available). I can watch this stream with an freewareplayer called VLC.
When using the JMF Studio tool, I can't watch the stream ... The Player is waiting for signals and breaks after 60 seconds. So, okay ... Maybe the JMF doesn't bring the right codec with it.
Now I've installed jffmpeg, but that doesn't help a lot. I write done the JAR File in Classpath and installed the Plugin, MimeType and Demultiplexer (as described) in the JMF Registry. The behaviour of JMF Studio is the same. Does anybody have an idea wether jffmpeg supports this kind of streaming
and/or what I can do to get the stream?! Maybe there is an better Plugin for my solution.
I can't suppose that nobody here ever tried to get an Mpeg2 or Mpeg4 multicast stream with JMF. There must be an solution.
Many thanks for your help and reply!
Jan Stanetzki

Hi funnyjanni,
May be I am writing this after 4 years.
I am also in the stage when you faced the same problem. You might have found the solution to this.
Please help me on this. I am trying to use jffmpeg to play UDP mutlicast stream.
Thanks
jklanka

UDP Multicast

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