有关多播通讯的深入讨论－－交换机对多播的支持？

[romijn]

本人做了一视频服务器的程序，传送视频图像采用，udp在局域网内发送组播，客户端程序启动的时候加入多播组，同时开始组内数据的接收。通过windows2000的网络监视器来查看客户端Windows2k的网络接收情况，发现没有开启视频客户端的时候，网络利用率很小，网络接收到一些数据桢但不是太大；开启了视频客户端后，网络利用率马上提升到了10%左右，数据桢也增加了许多。通过以上的情况可以断定我的多播程序是没有问题的。
本人的程序的问题如下：当视频服务器程序打开的时候，不管客户端有没有开启，交换机（本人的交换机为一般的10M/100M自适应的交换机）上所有的端口的数据交换指示灯不停的在闪烁，这时网络发生了堵塞，各个机器都无法通过网关上网。只要一关服务器程序，交换机马上正常，各台机器就可以上网。
有人说是这种情况是交换机不支持多播，把数据复制到各个端口，所以和广播的效果一样，所以会产生网络风波？是这样的吗？希望高手指点。

[romijn]

自己顶一下！

[stonesky]

这样会出现网络风暴吗？我认为是程序有问题

[awjx]

帮你顶一下

[romijn]

多谢这么多热心人，我觉得程序没有错！下面贴出来给大家看看。我的程序发送的数据量非常的大。
头文件
#include "Winsock2.h"
#pragma comment(lib,"Ws2_32.lib")

#define WM_MULTIPOINTEVENT WM_USER + 1001

class CMultiCast : public CObject
{
public:
void Close();
BOOL IsConnected();
static void Unintilize();
static void Initilize();
int Receive(char* lpData, int size);
int Send(char* lpData, int size);
BOOL Create(CString lpstrAddr, unsigned short port, HWND hWnd);
CMultiCast();
virtual ~CMultiCast();

private:
HWND m_hWnd;
SOCKET m_hSocket;
SOCKET m_hGroupSocket;
BOOL m_bConnected;

SOCKADDR_IN addr;
SOCKADDR_IN srcaddr;
};

[romijn]

程序代码
CMultiCast::CMultiCast()
{
m_hWnd = NULL;
m_bConnected = FALSE;
}

CMultiCast::~CMultiCast()
{

}

BOOL CMultiCast::Create(CString lpstrAddr, unsigned short port, HWND hWnd)
{

if(m_bConnected){
TRACE("Has Successfully Create the socket!\n");
return FALSE;
}
m_hWnd = hWnd;

int ret;
int cbRet = 0;
int nIP_TTL =1;//设置IP数据生存期
BOOL bFlag;
WSADATA wsaData;

//WORD version = MAKEWORD(2, 0);
WORD version = MAKEWORD(2, 2);
//初试化socket
ret = WSAStartup(version, &wsaData);
if(ret != 0)
TRACE("Initilize Error!\n");
//生成socket
m_hSocket = WSASocket(AF_INET, SOCK_DGRAM,/* IPPROTO_UDP,NULL,0,0);*/
IPPROTO_UDP, (LPWSAPROTOCOL_INFO)NULL, 0,
WSA_FLAG_OVERLAPPED | WSA_FLAG_MULTIPOINT_C_LEAF | WSA_FLAG_MULTIPOINT_D_LEAF);

if (m_hSocket == INVALID_SOCKET){
TRACE("WSASocket:%d\n",WSAGetLastError());
return FALSE;
}

bFlag = TRUE; // 设置套接字为可重用端口地址
ret = setsockopt(m_hSocket, SOL_SOCKET, SO_REUSEADDR, (char *)&bFlag,
sizeof (bFlag));

if(ret == SOCKET_ERROR){
TRACE("setsockopt:%d",WSAGetLastError());
return FALSE;
}
// 将套接字绑扎到用户指定端口及默认的接口
memset(&addr,0,sizeof(addr));
addr.sin_family = AF_INET;//PF_INET;
addr.sin_port = htons (port);
addr.sin_addr.s_addr = htonl(INADDR_ANY);
ret = bind (m_hSocket, (struct sockaddr FAR *)&addr,
sizeof(struct sockaddr));

if (ret == SOCKET_ERROR){
TRACE("bind: %d", WSAGetLastError());
return FALSE;
}
// 设置多址广播数据报传播范围（TTL）
ret = WSAIoctl(m_hSocket, SIO_MULTICAST_SCOPE, &nIP_TTL,
sizeof (nIP_TTL), NULL, 0, (unsigned long*)&cbRet, NULL, NULL);
if (ret == SOCKET_ERROR){
TRACE("SAIoctl(SIO_MULTICAST_SCOPE):%d\n",WSAGetLastError());
return FALSE;
}

//设置多播返回（LOOKBACK）

BOOL nLoopBack=FALSE;//m_JoinDlg.m_Loopback;
ret = WSAIoctl(m_hSocket,SIO_MULTIPOINT_LOOPBACK,&nLoopBack,sizeof(nLoopBack),
NULL,0,(unsigned long*)&cbRet,NULL,NULL);
if (ret == SOCKET_ERROR){
TRACE("WSAIoctl:%d\n",WSAGetLastError());
return FALSE;
}

memset(&srcaddr,0,sizeof(srcaddr));
srcaddr.sin_family=AF_INET;
srcaddr.sin_addr.s_addr=inet_addr(lpstrAddr);
srcaddr.sin_port=htons(port);

//WSABUF wsaCalleeData;
m_hGroupSocket = WSAJoinLeaf(m_hSocket, (PSOCKADDR)&srcaddr,
sizeof(srcaddr), NULL, /*&wsaCalleeData*/NULL, NULL, NULL, JL_BOTH);

if (m_hGroupSocket == INVALID_SOCKET){
m_bConnected = FALSE;
TRACE("WSAJoinLeaf():%d\n", WSAGetLastError());
return FALSE;
}

ret = WSAAsyncSelect(m_hGroupSocket, m_hWnd, WM_MULTIPOINTEVENT,
FD_WRITE | FD_READ | FD_QOS | FD_GROUP_QOS | FD_CONNECT);

if(ret == SOCKET_ERROR){
TRACE("WSAAsyncSelect():%d\n", WSAGetLastError());
m_bConnected = FALSE;
return FALSE;
}
m_bConnected = TRUE;
return TRUE;
}

int CMultiCast::Send(char *lpData, int size)
{
if(m_hSocket == INVALID_SOCKET)
return -1;
unsigned long nDataSent = 0;
int nReturnCode;
WSABUF wsaBuf;
wsaBuf.len = size;
wsaBuf.buf = lpData;
nReturnCode = WSASendTo(/*m_hSocket*/m_hGroupSocket, &wsaBuf, 1, &nDataSent,
0, (LPSOCKADDR)&srcaddr, sizeof(SOCKADDR), NULL, NULL);
if(nReturnCode == SOCKET_ERROR){
TRACE0("Error in send packets to the network!\n");
return -1;
}

return nDataSent;
}

int CMultiCast::Receive(char *lpData, int size)
{
int nReturnCode ;
WSABUF wsaRecvBuf;
wsaRecvBuf.buf = lpData;
wsaRecvBuf.len = size;
unsigned long cbRet = 0;

int iLen = sizeof (srcaddr);
int dFlag = 0;

nReturnCode = WSARecvFrom(m_hGroupSocket, &wsaRecvBuf, 1,
&cbRet, (unsigned long*)&dFlag, (struct sockaddr *)&srcaddr,
&iLen, NULL, NULL);
if(nReturnCode == SOCKET_ERROR){
if(WSAEWOULDBLOCK == WSAGetLastError())
TRACE("Socket will block!\n");
else{
if(WSAGetLastError() == WSA_IO_PENDING)
TRACE("IO is pending!\n");
else
return -1;
}
TRACE("RecvFrom Error:%d\n", WSAGetLastError());
}
//本次操作没有接收到数据
if(cbRet == 0)
return 0;

//通知父窗口读数据
return cbRet;
}

void CMultiCast::Initilize()
{
/*
WSADATA wsaData;
WORD version = MAKEWORD(2, 0);
int ret = WSAStartup(version, &wsaData);
if(ret != 0)
TRACE("Initilize Error!\n");
*/
}

void CMultiCast::Unintilize()
{
//closesocket(m_hGroupSocket);
//closesocket(m_hSocket);
if (WSACleanup() != 0){
TRACE("UnInitilize Error:%d\n", WSAGetLastError());
}
}

BOOL CMultiCast::IsConnected()
{
return m_bConnected;
}

void CMultiCast::Close()
{
closesocket(m_hSocket);
closesocket(m_hGroupSocket);
m_bConnected = FALSE;
}

[romijn]

if(!m_Socket.IsConnected()){
m_Socket.Create("224.0.0.99",2002,this->m_hWnd);
if(!m_Socket.IsConnected()){
AfxMessageBox("Socket初试化失败！");
return;
}
｝
//生成视频数据包装结构v
...
m_Socket.Send((char*)&v,sizeof(v))