multicast

问题 I have made a server that uses UDP multicast sockets. I am able to run the server on my local host and try with as many clients as I want. The problem is that i'm new to UDP and multicast and now I need to connect to another pc using the internet. For example: group = InetAddress.getByName(sendAdd); buf = senddata.getBytes(); packet = new DatagramPacket(buf, buf.length, group, senderPort); Is there anyway to host the UDP multicast server online? What InetAddress should I use in that case? 回答1

问题 The Apache ActiveMQ broker supports discovery with IP multicast. This feature is activated in the default 'demo' configuration (see below). I would like to implement the discovery feature in other languages (Delphi / Free Pascal). Is there some minimal code example or introduction page on the web which shows how this would be implemented in Java? If I understand correctly, the multicast would trigger an answer of the message broker, which contains information about IP and port of the message

问题 I'm writing a C++ application MyMasterApp which sends information (OSC via UDP) to multiple clients (about 5-10), which are mobile devices (Android or iPhone) via wifi. Each device is to receive unique information, of the same type. Probably about 100-200 bytes per device, and I'll be updating all devices at 30Hz. I could send a unique data packet to each device, or I could create one big structure which contains each of the unique bits of data for each device, with the target id, multicast

问题 If I launch 2 instances of the code below in the same computer the multicast works fine. If I launch it on a different computer in the same network I won't receive anything. Any idea what could be wrong? This code should compile as is. I am testing on win10 but I get similar results when I run this on linux. #include "pch.h" #define _WINSOCK_DEPRECATED_NO_WARNINGS #include "winsock2.h" #include <iostream> #include <conio.h> #include <thread> #include <ws2tcpip.h> #pragma comment(lib, "ws2_32

问题 Say I have N multicast-capable network interfaces. I am planning to bind N UDP sockets, one to each interface, and send to the same multicast ip/port. Is there a more direct/efficient approach than this? When receiving, I know you can listen over multiple interfaces using the same socket, but sending cannot be done with a single socket, or can it? 回答1: Another aproach is to use IP_MULTICAST_IF to change the interface used for sending multicast on the socket. With this approach, you would call

问题 If I have a Java program that listens to multicast data, how can I tell what the remaining TTL of the incoming datagram is? I know how to set the TTL on the sending multicast socket, but I want to know the remaining TTL of the arriving packet. 回答1: If you receive the UDP datagrams with a raw socket you can inspect the TTL (or anything else in the IP or UDP headers). There are lots of gotchas, though: Raw Sockets are non-native to Java (though at least one multi-platform 3rd party add-on is

问题 I try to implement a multicast communication to distribute some resources. I’m using jGroups for that, so I have reliable multicast and FIFO-Ordering. By doing that I wanna realise that with a distributed solution, that means without an master node that acts as a coordinator. Every node is able to start a distribution, so it is possible that two or more nodes are starting the distribution at the same time. When a node receives a distribution-message it will answer this. There are no

问题 I am writing an application streaming media file ( H264, fortmat I use now is *.MP4 ). I use Gstreamer with pipeline : gst-launch-1.0 filesrc location=/big_buck_bunny_720p_h264.mp4 ! qtdemux name=d d. ! h264parse ! rtph264pay config-interval=3 pt=96 mtu=1024 ! udpsink host=224.1.1.1 port=5000 And I use the following SDP file to receive stream: c=IN IP4 224.1.1.1 m=video 5000 RTP/AVP 96 a=rtpmap:96 H264/90000 In PC I can receive the stream and it playback normally. But now I want to receive

问题 i am writing a simple multicast application. i intend to run it on localhost. i have done the following: char *maddr; . . . sendfd = socket(...); struct sockaddr_in sasend; sasend.sin_family = AF_INET; sasend.sin_port = htonl(portno); inet_ntop(maddr, &(sasend.sin_addr.s_addr)); struct sockaddr_in sarecv; memcpy(&sarecv, &sasend); recvfd = socket(...); const int on = 1; setsockopt(recvfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); // can you explain why // this is needed bind(recvfd, &sarecv

问题 It works okay for any known IP like this: [udpSocket sendData:datatosend toHost:@"192.168.1.113" port:port withTimeout:-1 tag:0]; But when i'm trying to use broadband multicast, nothing logged and nothing goes on [udpSocket sendData:datatosend toHost:@"192.168.1.255" port:port withTimeout:-1 tag:0]; receiving works okay, i also tried 255.255.255.255 - the same. it doesn't give any error. 回答1: I found the solution: [udpSocket enableBroadcast:YES error:nil]; 来源： https://stackoverflow.com