IPX/SPX Programming Manual

Addressing
HP NonStop IPX/SPX Programming Manual—528022-001
2-9
Interface Libraries
Application processes request the NonStop IPX/SPX application to create a socket
when needed; the application specifies the type of service desired. The NonStop
IPX/SPX software returns a socket number that the application uses to reference the
new socket. The application then (optionally) binds the socket to a specific local
address and port, and sends or receives data on the socket. When the transfer of data
is complete, the application can (optionally) shut down the socket and close it. After a
socket open is completed, the socket persists across CPU crashes and process
switchovers.
The socket library functions provide access to both NonStop IPX/SPX and NonStop
TCP/IP. The socket() call can open either a NonStop TCP/IP process or a NonStop
IPX/SPX process, depending upon the arguments passed to it. Applications such as
Telserv can access both NonStop TCP/IP and NonStop IPX/SPX at the same time
using the socket interface.
The socket library routines for NonStop IPX/SPX and NonStop TCP/IP differ slightly.
Some of the differences are listed below:
•
NonStop IPX/SPX uses an address family AF_NV and an address type NV_ADDR
whereas NonStop TCP/IP uses AF_NET and IN_ADDR, respectively.
•
A number of socket calls that facilitate name-to-address translation for NonStop
TCP/IP are not used with NonStop IPX/SPX, as NonStop IPX/SPX uses the SAP
interface for this purpose.
•
The socket function call opens either the NonStop TCP/IP process or the
IPXPROTO process.
Beginning with the D30 RVU, a new version of the socket library provides upgraded
features, such as support for HP fault-tolerant applications written in C. Environment
setup now uses ADD DEFINE commands rather than the PARAM command, and
DEFINEINFO rather than getenv().
The socket library routines are based on the socket programmatic interface primitives
in the 4.3 BSD RVU of the UNIX operating system. However, the socket library
routines include extensions to adapt the Berkeley socket interface to NonStop Kernel
features such as nowait I/O.
For a detailed description of the socket library function calls available, see Section 5,
Library Routines.
SAP Interface
SAP allows a NetWare server to advertise its presence on the network. It also allows a
client to look for a specific server or for a class of servers.
Both waited and nowaited versions of SAP calls are provided. After an advertise
operation is completed, it is persistent across CPU failures and process switchovers.
Information about remote servers and services is not checkpointed. If a switch occurs,
the IPXPROTO process rebuilds the SAP table by broadcasting a SAP query to all
servers on the LAN.