some implementations, broadcast packets may also be received when a datagram socket is bound to a specific address. Stream sockets Connection-oriented sockets, which use Transmission Control Protocol (TCP), Stream Control Transmission Protocol (SCTP) or Datagram Congestion Control Protocol (DCCP). A stream socket provides a sequenced and unique flow of error-free data without record boundaries, with well-defined mechanisms for creating and destroying connections and reporting errors. A stream socket transmits data reliably, in order, and with out-of-band capabilities. On the Internet, stream sockets are typically implemented using TCP so that applications can run across any networks using TCP/IP protocol. Raw sockets Allow direct sending and receiving of IP packets without any protocol-specific transport layer formatting. With other types of sockets, the payload is automatically encapsulated according to the chosen transport layer protocol (e.g. TCP, UDP), and the socket user is unaware of the existence of protocol headers that are broadcast with the payload. When reading from a raw socket, the headers are usually included. When transmitting packets from a raw socket, the automatic addition of a header is optional. Most socket application programming interfaces (APIs), for example, those based on Berkeley sockets, support raw sockets. Windows XP was released in 2001 with raw socket support implemented in the Winsock interface, but three years later, Microsoft limited Winsock's raw socket support because of security concerns. Raw sockets are used in security-related applications like Nmap. One use case for raw sockets is the implementation of new transport-layer protocols in user space. Raw sockets are typically available in network equipment, and used for routing protocols such as the Internet Group Management Protocol (IGMP) and Open Shortest Path First (OSPF), and in the Internet Control Message Protocol (ICMP) used, among other things, by the ping utility. Other socket types are implemented over other transport protocols, such as Systems Network Architecture and Unix domain sockets for internal inter-process communication. Socket states in the client-server model Computer processes that provide application services are referred to as servers, and create sockets on startup that are in the listening state. These sockets are waiting for initiatives from client programs. A TCP server may serve several clients concurrently by creating a unique dedicated socket for each client connection in a new child process or processing thread for each client. These are in the established state when a socket-to-socket virtual connection or virtual circuit (VC), also known as a TCP session,