TS Supplement (Includes RFC-1006 Support)

Introduction to the Tandem TCP/IP Subsystem

Introduction to RFC-1006

1–8 107751 Tandem Computers Incorporated

Sockets Interface

The TCP/IP subsystem components interface with the TCP/IP process through the

sockets interface, as shown in Figure 1-6. The Tandem socket library routines are

based on the sockets programmatic interface primitives in the UNIX operating system

(BSD 4.3). In addition, the Tandem socket library routines include extensions, such as

NOWAIT I/O, to adapt the Berkeley sockets interface to the Tandem NonStop Kernel

operating system.

TCP/IP Subsystem Components

The TCP/IP processes include the following processes and protocols, as described

below.

The TCP/IP process consists of the following protocols:

The TCP protocol provides the transport control protocol.

The User Datagram Protocol (UDP) is a connectionless transport protocol and

provides different transport services. It is not used with RFC-1006.

The Internet Protocol (IP) is the internetworking protocol, to ISO 8473 (CLNP).

The Internet Control Message Protocol (ICMP) is a module within IP that

reports errors and provides administrative and status messages.

The Address Resolution Protocol (ARP) translates Internet protocol addresses

to physical addresses and hides the physical addresses from the upper layers.

The Subnetwork Access Protocol (SNAP) is a required interface between the IP

layer and the Logical Link Control (LLC) sublayer in LANs.

The File Transfer Protocol (FTP) is a widely used Application Layer standard

used to transfer files between hosts.

The Simple Mail Transfer Protocol (SMTP) is a widely used Application Layer

standard that defines how to transmit mail messages between users.

The FINGER protocol provides a means to obtain status information on users

currently logged onto a particular system.

The LISTNER process: In the Tandem TCP/IP environment, this process functions

as a super server for ECHO, FTP, and FINGER and invokes the appropriate

Tandem server as connection requests for FTP, ECHO, and FINGER services are

received on well-known TCP ports.

The OSI/TS server does not use the LISTNER process as do FTP, ECHO, and

FINGER servers. The OSI/TS server directly performs PASSIVE opens by itself

and does not rely on the LISTNER process.

The TELNET subsystem provides a virtual terminal protocol that allows a user of

one host to log onto to a remote host and to appear as a local user to the remote

host.