The Novell NetWare Core Protocol (NCP) manages access to the primary NetWare server resources. NCP makes procedure calls to the NetWare File Sharing Protocol (NFSP) that services requests for NetWare file and print resources. NCP is the principal protocol for transmitting information between a NetWare server and its clients.

NCP handles login requests and many other types of requests to the file system and the printing system. NCP is a client/server LAN protocol. Workstations create NCP requests and use IPX to send them over the network. At the server, NCP requests are received, unpacked, and interpreted.

NCP services include file access, file locking, security, tracking of resource allocation, event notification, synchronization with other servers, connection and communication, print services and queue management, and network management.

NCP uses the underlying Internetwork Packet Exchange Layer Services (IPX). More recent NetWare versions (after NetWare 5.0) can also use TCP/IP.

Protocol Structure

The format of the NCP Request header is shown below.

• Request type - Identifies the packet type:
  • 1111H Allocate slot request
  • 2222H File server request.
  • 3333H File server reply.
  • 5555H Deallocate slot request.
  • 7777H Burst mode packet (BMP).
  • 9999H Positive acknowledge.
  • H signifies hexadecimal notation.
• Sequence number - Number used by the workstation and file server to identify packets which are sent and received.
• Connection number low - Low connection ID number assigned to the workstation.
• Task number - Identifies the operating system e.g., DOS, task.
• Connection number high - High Connection ID number assigned to the workstation. Used only on the 1000-user version of NetWare, on all other versions will be set to 0.
• Request code - Identifies the specific request function code.

The structure of the NCP Reply header is the same as the Request header, but the last 2 bytes differ after Connection Number High. This is shown below:

• Completion code
• Connection status

Completion code - The completion code indicates whether or not the Client's request was successful. A value of 0 in the Completion Code field indicates that the request was successful. Any other value indicates an error.

Connection status - The fourth bit in this byte will be set to 1 if DOWN is typed at the console prompt, to bring the server down.

Related protocols: IPX, SPX, RIP, NLSP, NCP, NetWare

Sponsor Source: NetWare Core Protocol (NCP) is a Novell protocol.

Reference: http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/netwarep.htm: NetWare Protocols