3

I am using UDPClient to send multicast request and receive response from various clients on the network. I am able to send request and also getting response, but response that I get is very slow. It take 2-3 minutes to get response from all the clients. On send request on the network I checked in the WireShark, there I am seeing response in milliseconds from all the clients only in test program. It is taking lot of time. Can anyone guide what mistake I might be doing? Following is the code. Please guide me on this. I have been stuck on this issue for the last 2 days.

public class Trinity_WSDiscovery : IDiscoveryService 
{
        #region IDiscoveryService Members
        public event EventHandler FoundNewDevice;
        public event EventHandler EndOfDiscovery;
        DeviceBinding m_DeviceBinding;
        bool IsFindComplete = false;
        Thread receiveThread;
        UdpClient sock ;        
        IPEndPoint RemoteIpEndPoint = new IPEndPoint(System.Net.IPAddress.Any, 0);
        IPEndPoint iep = new IPEndPoint(System.Net.IPAddress.Parse("239.255.255.250"), 3702);
        UdpState udpState = new UdpState();
        XmlDocument xmlDoc = new XmlDocument();

    public void Start()
    {
        //Need to create new object every time we start discovery because
        //every time udp buffer needs to be flushed and restarted
        sock = new UdpClient();
        string str = "<?xml version='1.0' encoding='utf-8'?><soap:Envelope xmlns:soap=\"http://www.w3.org/2003/05/soap-envelope\" xmlns:d=\"http://schemas.xmlsoap.org/ws/2005/04/discovery\" xmlns:wsadis=\"http://schemas.xmlsoap.org/ws/2004/08/addressing\" xmlns:dn=\"http://www.onvif.org/ver10/network/wsdl\"><soap:Header><wsadis:MessageID>uuid:" + System.Guid.NewGuid().ToString() + "</wsadis:MessageID><wsadis:To>urn:schemas-xmlsoap-org:ws:2005:04:discovery</wsadis:To><wsadis:Action>http://schemas.xmlsoap.org/ws/2005/04/discovery/Probe</wsadis:Action></soap:Header><soap:Body><d:Probe><d:Types /> <d:Scopes/></d:Probe></soap:Body></soap:Envelope>";
        byte[] data = Encoding.ASCII.GetBytes(str);
        sock.Send(data, data.Length, iep);
        sock.JoinMulticastGroup(System.Net.IPAddress.Parse("239.255.255.250"));            
        IPEndPoint iep1 = new IPEndPoint(System.Net.IPAddress.Any, 0);            
        udpState.ipEndpt = RemoteIpEndPoint;
        udpState.udpClient = sock;           
        BeginReceive();           
    }

    public void BeginReceive()
    {
        Thread.Sleep(100);
        if (sock.Available > 0)
        {
            sock.BeginReceive(new AsyncCallback(ReceiveCallback), udpState);
        }
        else
        {
            FindComplete();
        }
    }

    public void ReceiveCallback(IAsyncResult ar)
    {
        UdpClient udpClient = (UdpClient)((UdpState)(ar.AsyncState)).udpClient;
        IPEndPoint ipEndpt = (IPEndPoint)((UdpState)(ar.AsyncState)).ipEndpt;
        Byte[] receiveBytes = udpClient.EndReceive(ar, ref ipEndpt);
        string receiveString = Encoding.ASCII.GetString(receiveBytes);
        if (receiveString.Contains("NetworkVideoTransmitter"))
        {
            xmlDoc.LoadXml(receiveString);
            XmlNodeList list = xmlDoc.GetElementsByTagName("XAddrs", "http://schemas.xmlsoap.org/ws/2005/04/discovery");
            XmlNode node = list[0];
            string strEndPoints = node.FirstChild.Value;
            string[] strEndPointList = Regex.Split(strEndPoints, " ");
            OnFoundDevice(strEndPointList);
        }
        BeginReceive();
    }

}`

4

3 回答 3

1

为什么需要Thread.Sleep？

这可能会导致延误。

于 2011-05-17T07:42:42.540 回答
1

我看到您的问题有两个可能的原因。

  1. 似乎您在设计中为每个响应客户端的每个响应都设置了 100 毫秒的延迟。你在 BeginReceive 方法中做的第一件事就是睡觉，不管是否有数据。对于每个响应，您（正确地）调用 BeginReceive 来注册您的新接收回调。但由于一次只注册了一个 ReceiveCallback，处理每个响应至少需要 100 毫秒。如果您同时收到 30 个传入的客户端呼叫，则最后一个将延迟 3 秒。

  2. 在您的 ReceiveCallback 中，您调用您的方法 OnFoundDevice。这看起来像一个回调或事件处理程序。此回调花费的任何执行时间都将延迟下一个处理的答案。如果回调需要 1 分钟，则下一个响应将延迟 1 分钟（在您的 BeginReceive 方法中加上 100 毫秒）。

建议的解决方案： 1. 从您的 BeginReceive 中删除延迟和条件，像这样。

public void BeginReceive()
{
     sock.BeginReceive(new AsyncCallback(ReceiveCallback), udpState);
}
  1. 查看 OnFoundDevice 所做的工作。如果耗时，则将调用编组到另一个线程（例如，通过在线程池上执行 QueueUserWorkItem）。

如果您在 BeginReceive 中使用 sleep 的原因是为了找到何时停止侦听数据的标准，您可以在 Start 方法中为此启动一个计时器，并在预定时间后或未收到数据时在您的套接字上调用 Close在设定的时间跨度内。

我希望这能够帮到你。

于 2011-09-05T08:01:46.110 回答
0

你可以使用像这样的阻塞调用超时......因为看起来你的程序在等待时不想做任何其他工作......这样如果响应在不到 100 毫秒内出现，你就不必等那么久。

udpAdmin.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 100)
receiveBytes = sock.Receive(RemoteIpEndPoint)  'waits here till you get a response or until timeout, whichever comes first.
于 2014-09-27T00:04:46.037 回答