Sep 18, 2011 · Once a packet reaches a host using its IP address, the packet needs to be given to one of the applications on this machine. To determine which application should get the packet, it needs demultiplexing logic, which is based on ports. UDP has port information which is used by IP to deliver the packet to appropriate application.

Basically I want to create a protocol where I send a udp packet and then I expect a response. Just like the HTTP protocol for every request there is a response. This code works if the server is on a different computer. There might be the case where the server and client are on the same computer though. Here is the server:

Jun 17, 2010 · A single IP_ADDRANY-bound UDP server should be able to appear to respond on the same dynamically-assigned IP address a packet is received on. Luckily, there is another way. Depending on your system's support you can make use of the IP_PKTINFO socket options to set or receive ancillary data about a message.

Dec 26, 2010 · Connectionless protocols (Like IP and UDP) are used for example with the Video Conferencing when you don't care if some packets are lost , while you have to use a Connection-Oriented protocol (Like TCP) when you send a File because you want to insure that all the packets are sent successfully (actually we use FTP to transfer Files). Edit:

May 22, 2012 · In regards to why ports are specified during a multicast subscription - it's because multicast IP is just that - IP only. "ports" are a property of the upper protocols (UDP and TCP). You can read more about how multicast IP addresses map to multicast ethernet addresses at various sites. The Wikipedia article is about as good as it gets:

Jun 18, 2014 · I have a server with a couple of different IP addresses. At this point, each IP can recieve a UDP request, but it is always the same IP that replies, which the requesters do not like. To make a long story short, this is all the essential code:

The application will run on a LAN (not internet). I've been assuming that if my MTU is 1500 then thats how big a UDP payload can be, but I'm not sure if the UDP header is meant to fit within that too. I'm suspecting that if I send a UDP packet with a 1500 byte payload and the machine MTU is 1500 bytes will it end up sending two packets?

If the network protocol is IP, the unit of data is called Datagram. At the transport layer, if the protocol is UDP, we use datagram there as well. Hence, we differentiate them as UDP Datagram, IP Datagram. Frame: Physical layer representation. Packet: It is a more generic term used either transport layer or network layer.

Sep 28, 2016 · Use the Name of the Server instead of the IP. Often in corporate networks the IP address of a PC will change periodically (usually 3-4 weeks) so using the Name of the server which doesn't change rather than the IP address will solve issue. The Net library will accept either an ip or computer name when constructing the UdpClient. –

Oct 20, 2017 · The idea would be to send a discovery message containing your ip address and name. Then in the receive message function add the ip-name pairs to a List of devices. Add a little logic to avoid duplicates and update Ip address if the ip changes for a given name. As a bonus, you can have each device send the list of devices they know about.