Datagram Support

[Netbios is not supported on Windows Vista, Windows Server 2008, and subsequent versions of the operating system]

The following are the datagram support commands:

  • NCBDGRECV (receive datagram)
  • NCBDGRECVBC (receive broadcast datagram)
  • NCBDGSEND (send datagram)
  • NCBDGSENDBC (send broadcast datagram)

Datagram support provides unreliable connectionless data transfer. The message is a single data frame whose size is limited to a MAC frame minus any headers. The protocol driver ensures that the message is transmitted to the network medium. The receiver does not generate a response to the sender to indicate that the datagram was received. Therefore, unreliable connectionless data transfer requires fewer system resources than reliable connection-oriented data transfer.

The NCBDGRECV and NCBDGSEND commands transfer a datagram to a specified NetBIOS name. If the specified name is a unique name, the datagram is received by the single process that registered the name. If the specified name is a group name, the datagram is received by all processes that registered the name. This process is shown in the following illustration.

 

Bb870891.netbiosa(en-us,VS.85).png

 

The NCBDGSENDBC command broadcasts a datagram to all computers on the network. The datagram is received by all processes that have issued the NCBDGRECVBC command, as shown in the following illustration.

 

Bb870891.netbiosb(en-us,VS.85).png

 

 

 

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Build date: 7/2/2010

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