Microsoft KB Archive/203051

= Description of Microsoft NWLINK IPX/SPX-Compatible Transport =

Article ID: 203051

Article Last Modified on 10/30/2006

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APPLIES TO


 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft BackOffice Server 4.0
 * Microsoft Windows NT Workstation 3.1
 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition

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This article was previously published under Q203051





SUMMARY
This article describes the basic components in the Microsoft NWLINK IPX/SPX Compatible Transport.



MORE INFORMATION
The following table defines some components included in the NWLINK IPX/SPX Compatible Transport protocol suite. Component    Definition --- IPX          Internet Packet eXchange (IPX) is a connectionless, routable protocol. It provides no session services by itself. IPX Packet   An IPX packet contains fields for Checksum, Length, Transport Control (hop count), Packet Type, Destination Address, and Source Address. IPX Address  An IPX address contains Network, Node, and Socket. Network      The External network numbers are defined per network segment. The Internal network numbers are defined per server for any server which requires one. All network numbers, Internal or              External, must be unique for the entire network.

NOTE: All NetWare servers require an Internal network number. Windows servers require Internal network numbers only in the following specific circumstances:
 * Windows servers using multiple NIC cards require an Internal network number.
 * Windows servers using only a single NIC card, but two or more frame types bound to it, require an Internal network number.
 * Some programs, such as Btrieve, require Windows to define an Internal network number to function correctly.

Component  Definition

Node       An address assigned to a node can be a MAC address, a logically assigned address (Token Ring), or the number one (1) if an Internal network number is specified. For the local IPX destination addresses, the Node address maps to the hardware address of the network node. This eliminates the requirement for a separate address resolution protocol such as ARP for IP. Socket     Some IPX Sockets are designated for a specific process, some are negotiated for a session. The following table lists some well known sockets:

Process  Socket

NCP      451 SAP      452 RIP      453 NetBIOS  455 NMPI     551 A Packet Type describes the protocol included in the frame. The following table lists some of the protocols and their hexadecimal and decimal values:

Hex  Dec   Protocol

00   00    SAP, NSP, other IPX broadcasts 01   01    RIP 04   04    SAP, NetBIOS sessions and directed datagrams 05   05    SPX 11   17    NCP 14   20    NetBIOS name resolution broadcasts

The IPX frame type describes the method of encapsulating data in an IPX packet, and is distinguished by the header of network packet. Network nodes with dissimilar frame types cannot communicate with each other. The following table lists the fields present in the header for each frame type:

Protocol       Ethernet - 802.3   Etype   LLC   SNAP   Token - 802.           X                  X 802.3           X Ethernet II     X                  0x8137 Ethernet SNAP  X                  X       X Token                              X              X Token SNAP      X                  X       X

Component  Definition - SPX        Sequenced Packet eXchange (SPX) is a Session management protocol, which provides connection oriented services for applications that do not require file or print I/O. Original implementation requires an ACK for every packet sent. SPX II     SPX II includes performance enhancements such as burst mode support. NCP        NetWare Core Protocol (NCP) provides standard file and print services to NetWare servers. This is the Novell equivalent of           the Microsoft SMB protocol. SAP        Service Advertising Protocol (SAP) facilitates the creation of             a database of network services. The SAP database is            maintained by periodic SAP broadcasts. NOTE: Clients can attempt to locate network services either by directly querying the NetWare Bindery, or by broadcasting a SAP request for the requested service. Component           Definition -- RIP                 Routing Information Protocol (RIP) facilitates the exchange or routing information on an IPX network. Routing Services    Routing services allow routers to determine the fastest route using Hop counts and ticks. Every router on a network broadcasts every 60 seconds. All servers with an Internal Network Number must perform periodic RIP broadcasts. Address Resolution  Address resolution allows clients to map a destination IPX address to a MAC address. This provides the same functionality for IPX as ARP provides for IP. NBIPX               NetBIOS over IPX (NBIPX) provides connection oriented session support for NetBIOS applications and the SMB protocol. NetBIOS support over IPX is provided on most Microsoft implementations of NWLink. NOTE: Windows requires NetBIOS over IPX for client SMB support through the Workstation service. Component           Definition -- NMPI                Name Management Protocol on IPX (NMPI) is Microsoft's                     protocol for name management support when you use IPX without the NetBIOS interface. This process of                    routing the SMB protocol directly through IPX is known as Direct Hosting. NOTE: Windows 95 and Windows for Workgroups 3.11 use Direct Hosting by default. Windows NT Server 3.5 and later support Direct Hosting using the Server service only.

Keywords: kbfaq kbinfo kbnetwork KB203051

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