NetWare Core Protocol

NetWare Core Protocol ( NCP short ) is a system developed by Novell network protocol.

It was developed for the network operating system and NetWare is a connection-oriented, proprietary protocol that is based on SPX / IPX. In the OSI model, it is sufficient from the transport layer to the application layer. It used to exchange data between the operating system Netware client and Netware servers. With the socket number 0x0451, it transfers the data of the file, print and connection services. From Netware 5 NCP can also via TCP / IP to be transported; IPX is no longer necessary. Unlike TCP / IP, it does not have a window size - that is, each packet must be acknowledged individually. With the introduction of the Burst Mode Protocol ( BMP) as a special NCP packet type Novell has increased the throughput by NCP. Now you can receive up to 64kB without any further requirement.

Construction of a request packet

Typical structure of a request packet:

Request Type to Package ID:

  • 0x1111 Allocate slot request
  • 0x2222 File server request
  • 0x3333 File server reply
  • 0x5555 Deallocate slot request
  • 0x7777 burst mode packet (BMP)
  • 0x9999 Positive acknowledge

Sequence Number: A byte serial number of the packets.

Connection Number Low: Lower byte of the connection number of the client.

Task Number: Number of the process to which the packet belongs.

Connection Number High: Upper byte of the connection number of the client.

Request Code: function number of the package.

The structure of the reply packet is similar to the request packet with the exception of two bytes after Connection Number High:

Completion Code: Result of the request. Zero is called the SUCCESSFUL and nonzero values ​​indicate the error number.

Connection Status: The fourth bit is one, when the server is shutting down.

The protocol in the OSI model