A self-contained package of data that carries enough information to be routed from source to destination independently of any previous and subsequent exchanges. A datagram service transports datagrams on a ‘best-effort’ basis. There is a nonzero probability that any datagram will be lost or damaged before reaching its destination. The order in which datagrams are submitted by the source is not necessarily preserved upon delivery. In some networks there is the possibility that a datagram may be duplicated and delivered to the destination more than once. It is the responsibility of the application to guard against errors arising from datagram loss or duplication.