This section outlines the points you must note with SOCKETS(POSIX) and XTI(POSIX) applications with regard to the BS2000 BCAM transport system. Please refer to the manual "BCAM" for more detailed information.
BCAM as the SOCKETS(POSIX) and XTI(POSIX) communications manager
BCAM supports several communications architectures as the basis of the data communications system for BS2000 hosts. Socket and XTI applications can communicate via the TCP/IP and UDP/IP protocols of the Internet architecture. The communications system is managed with BCAM administration commands. The most important BCAM commands in this respect are BCIN (generate end systems dynamically) and BCSHOW (get state information, e.g. port assignments). You can also use the corresponding SDF commands instead of BCIN and BCSHOW.
Assigning a socket or transport endpoint a special Internet address
When SOCKETS(POSIX) is used on a system with more than one Internet port, linking of a socket to a special Internet port is supported. For this purpose it may be necessary to set the SO_REUSEADDR option with the setsockopt() function.
Relevant settings with the BCAM transport system
The BCAM commands which have effects on SOCKETS(POSIX) and XTI(POSIX) applications are shown below. The BCAM commands and their parameters are described in detail in the "BCAM" manual.
BCAM commands DCSTART and BCMOD (BCAM limits)
The MAXNPA, MAXNPT and MAXCNN operands limit the number of network applications and connections.
BCAM command BCTIMES (BCAM time settings)
The CONN operand limits the wait time for connection requests.
The DATAGRAM operand limits the linger period for connectionless transport service messages.
The LETT operand limits the linger period for connection-oriented transport service messages.
BCAM command BCOPTION (BCAM mode options)
The BROADCAST operand defines whether the host is allowed to receive broadcast messages. There are no restrictions on sending broadcast messages.
BCAM commands BCMOD and DCOPT (predefine/modify DCSTART parameters)
The FREEPORT# operand defines the first free port number that can be assigned dynamically by BCAM to an application. PRIVPORT# defines the first socket port number that can be assigned to non-privileged and privileged applications.
FREEPORT# must always be greater than or equal to PRIVPORT#.
Support for the Domain Name Service (DNS)
SOCKETS(POSIX) supports the DNS concept if the subsystem SOCKETS(BS2000) and/or the DNS Resolver from the product interNet Services (formally TCP-IP-SV) have been configured and started, see the manual "interNet Services Administrator Guide".
The DNS collects information on the hosts connected to a network and makes this information available to all hosts via the network.
The following DNS functionality is available:
for gethostbyname(), gethostbyaddr()
DNS Resolver functionality in interNet Services (TCP-IP-SV)
DNS Resolver functionality in SOCKETS(BS2000)for getipnodebyname(), getipnodebyaddr(), getaddrinfo(), getnameinfo()
DNS Resolver functionality in SOCKETS(BS2000)