NetWare Core Protocol
| application | NCP | ||||
| transport | TCP | ||||
| Internet | IP ( IPv4 , IPv6 ) | ||||
| Network access | Ethernet |
Token bus |
Token ring |
FDDI | ... |
The NetWare Core Protocol ( NCP ) is a network protocol developed by Novell .
It was developed for the NetWare network operating system and is a connection-oriented , proprietary protocol based on SPX / IPX . In the OSI model, it ranges from the transport layer to the application layer. It is used to exchange data between the operating system Netware client and the Netware server. With the socket number 0x0451 it transfers the data of the file, print and connection services. As of Netware 5, NCP could also be transported via TCP / IP ; IPX was no longer necessary. In contrast to TCP / IP, it has no window size - that is, each packet must be confirmed individually. With the introduction of the Burst Mode Protocol (BMP) as a special NCP packet type, Novell has increased the throughput of the NCP. Since then, up to 64 kB can be received without further request.
Structure of a requirements package
Typical structure of a requirements package:
| Request Type |
| Sequence Number |
| Connection number low |
| Task Number |
| Connection number high |
| Request code |
| Data (variable length) |
Request type for package identification:
- 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: One byte consecutive 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 package belongs.
Connection Number High: Upper byte of the connection number of the client.
Request Code: Function number of the package.
The structure of the response packet is the same as the request packet with the exception of the two bytes after Connection Number High :
| Completion Code |
| Connection status |
Completion Code: Result of the request. Zero means SUCCESSFUL and the values not equal to zero indicate the error number.
Connection Status: The fourth bit is one if the server is currently being shut down.
The protocol in the OSI model
| OSI layer | English | classification | TCP / IP layer | classification | IPX / SPX / NCP | |
|---|---|---|---|---|---|---|
| 7th | application | Application | Application- oriented |
application | End to end (multihop) |
NCP |
| 6th | presentation | Presentation | ||||
| 5 | meeting | session | ||||
| 4th | transport | transport | Transport- oriented |
Host to host |
SPX | |
| 3 | Mediation | Network | Internet | Point to point |
IPX | |
| 2 | Fuse | Data link | network |
Ethernet Token Ring FDDI ARCNET |
||
| 1 | Bit transfer | Physical | ||||