network protocols handbook.pdf

283Protocols GuideNovell NetWare and ProtocolsProtocol NameNCP: NetWare Core ProtocolProtocol DescriptionThe Novell NetWare Core Protocol (NCP) manages access tothe primary NetWare server resources. NCP makes procedurecalls to the NetWare File Sharing Protocol (NFSP) that servicesrequests for NetWare file and print resources. NCP is the principalprotocol for transmitting information between a NetWareserver and its clients.NCP handles login requests and many other types of requeststo the file system and the printing system. NCP is a client/serverLAN protocol. Workstations create NCP requests and use IPXto send them over the network. At the server, NCP requests arereceived, unpacked, and interpreted.NCP services include file access, file locking, security, trackingof resource allocation, event notification, synchronization withother servers, connection and communication, print servicesand queue and network management.NCP uses the underlying Internetwork Packet Exchange LayerServices (IPX). More recent NetWare versions (after NetWare5.0) can also use TCP/IP.Protocol StructureThe format of the NCP Request header is shown below.Sequence numberTask numberRequest code8 16bitRequest typeConnection number lowConnection number high1000-user version of NetWare, on all other versionswill be set to 0.• Request code - Identifies the specific request functioncode.The structure of the NCP Reply header is the same as the Requestheader, but the last 2 bytes differ after Connection NumberHigh. This is shown below:Completion codeConnection status• Completion code - The completion code indicateswhether or not the Client’s request was successful.A value of 0 in the Completion Code field indicatesthat the request was successful. Any other value indicatesan error.• Connection status - The fourth bit in this byte will beset to 1 if DOWN is typed at the console prompt, tobring the server down.Related protocolsNetWare, SPX, RIP, NLSP, IPXSponsor SourceNetWare Core Protocol (NCP) is a Novell protocol.Referencehttp://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/netwarep.htmNetWare Protocols• Request type - Identifies the packet type:1111H. Allocate slot request2222H 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 workstationand file server to identify packets which are sent andreceived.• Connection number low - Low connection ID numberassigned to the workstation.• Task number - Identifies the operating system e.g.,DOS, task.• Connection number high - High Connection ID numberassigned to the workstation. Used only on the