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Creating a UDP socket

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• Creating a socket in general
  • Defining a socket variable in general:

    int s; s = socket(domain, socket-type, protocol-used); // Creates a socket

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  • Meaning of the parameters:

    domain parameter: PF_INET = will use the IPv4 protocol (PF = protocol family) PF_INET6 = will use the IPv6 protocol socket-type parameter: SOCK_DGRAM = UDP socket SOCK_STREAM = TCP socket protocol parameter: used to select a network protocol that will/can provide the service 0 = use the default network protocol SOCK_DGRAM's default protocol is: UDP SOCK_STREAM's default protocol is: TCP

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  • Result of the socket system call:

    The socket() system call will: create an entry in the ("per-process") descriptor table inside the Operating System Graphically: The descriptor table is used to: record the state of all opened system resources by the process (running program) Example of system resources: Files Pipes Sockets             Etc., etc

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• Creating a UDP socket
  • System call to create a UDP socket:

    int s; s = socket(PF_INET, SOCK_DGRAM, 0); // Creates a IPv4 UDP socket

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• Associating a UDP socket with an UDP port (in the kernel)
  • Fact:

    After creating a UDP socket, we still need to associate the socket with an UDP port inside the Operating System

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  • But first:

    We need to learn: How to specify a Internet network address (that identifies a UDP port)