multicast application.....???

hi all....

i m assigned this job to test my network which comprises of 8 routers for multicasting (pim,dvmrp etc) but for this i need a multicast application(obviously..:)) can anybody tell me where i can get a good one (client and server) which works accross different networks???

thanx

udpcast worked for me about two years ago. I used it in a netboot/backup-situation where the used ramdisk (for booting) was under four mb's. You'll find more information at http://udpcast.linux.lu/

Hi

Actually, I was a little motivated to write a little multicast client-server application
myself. The server sends a string once a second (XSleep[1]) to a multicast address.
I've set the TTL to 3 to enable small hops, if the routers support multicasting.
The clients join the multicast group to receive the string. The code does work
as well under Windows as Linux - just a few lines (headers) have to be modified.

This is for educational purposes only :) I tried to be as close to the "common
notation" as possible to simplify comparison with other source codes out there.

The server:

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <winsock.h>

#include "XSleep.h"

int main(){
        WSADATA wsda;                               
        WSAStartup(0x0101,&wsda);        // winsock version number

        int sockfd;
        struct sockaddr_in multicast_sockaddr;
       
        char multicast_ip[16] = "224.000.111.222";
        unsigned short multicast_port = 12345;
        unsigned char multicast_ttl = 3;

        char probe[17] = "Hello World! 000";
        unsigned int probe_length = strlen(probe);
        int counter=0;

// get a socket file descriptor and set the socket option to multicast
        sockfd = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
        setsockopt(sockfd,IPPROTO_IP,IP_MULTICAST_TTL, (const char *)&multicast_ttl, sizeof(multicast_ttl));

// initialise the multicast sockaddr
        memset(&multicast_sockaddr,0,sizeof(multicast_sockaddr));
        multicast_sockaddr.sin_family = AF_INET;
        multicast_sockaddr.sin_addr.s_addr = inet_addr(multicast_ip);
        multicast_sockaddr.sin_port = htons(multicast_port);

// start the server
        while(1){
                sprintf(probe,"Hello World! %.3d",counter%1000);

                if ((unsigned)sendto(sockfd,probe,probe_length,0,
                        (struct sockaddr *) &multicast_sockaddr,sizeof(multicast_sockaddr))!=probe_length){
                                printf("sendto failed. Aborting server.");
                                exit(1);
                } else  printf("Sending: \"%s\"\n",probe);
               
                XSleep(1000);
                counter++;
       
        }

        WSACleanup();
        closesocket(sockfd);

        return 0;
}

---

The client:

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <winsock.h>

int main(){
        WSADATA wsda;                               
        WSAStartup(0x0101,&wsda);        // winsock version number

        int sockfd;
        struct sockaddr_in multicast_sockaddr;
       
        char multicast_ip[16] = "224.000.111.222";
        unsigned short multicast_port = 12345;
        struct ip_mreq multicast_request;

        char probe[17];
        unsigned int probe_length;

// get a socket file descriptor
        sockfd = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);

// initialise the multicast sockaddr
        memset(&multicast_sockaddr,0,sizeof(multicast_sockaddr));
        multicast_sockaddr.sin_family = AF_INET;
        multicast_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
        multicast_sockaddr.sin_port = htons(multicast_port);

// bind to the port
        bind(sockfd,(struct sockaddr *) &multicast_sockaddr,sizeof(multicast_sockaddr));

// specify and join the multicast group and accept any interface       
        multicast_request.imr_multiaddr.s_addr=inet_addr(multicast_ip);
        multicast_request.imr_interface.s_addr=htonl(INADDR_ANY);
        setsockopt(sockfd, IPPROTO_IP,IP_ADD_MEMBERSHIP,(const char *) &multicast_request, sizeof(multicast_request));

        while(1){
                probe_length=recvfrom(sockfd,probe,17,0,NULL,0);
                if ( probe_length < 0){
                                        printf("recvfrom failed. Aborting client.");
                                        exit(1);
                } else{
                                probe[16]=0;
                                printf("Received: \"%s\"\n",probe);
                }
        }

        WSACleanup();
        closesocket(sockfd);

        return 0;
}

---

Do not forget to link the library WSock32.lib. If you want to read
more about multicasting, there is a pretty good introduction[2]
available. I would suggest to play with different settings (pim,...),
in particular with heavy load traffic. (Guus' link).

Cheers :)

[1] http://www.codeguru.com/Cpp/misc/misc/article.php/c211/
[2] http://userpage.fu-berlin.de/~tangua...ticast_rou.htm