Technical data

1.1.4 Application Layer
The top layer of the TCP/IP protocol suite, the Application layer handles the details
of the particular application, protocol, or user command; it is not concerned with
the movement of data across the network.
TCP/IP Services supports the following TCP/IP applications, protocols, and user
services:
Remote Computing Services
Remote computing applications enable networked users to run software on remote
systems. TCP/IP Services include the following remote computing application
components:
• TELNET enables remote login to other hosts in the network. Compaq TCP/IP
Services provides simultaneous multiple sessions, IBM3270 terminal emulation
(TN3270) and two interface formats: DCL style and UNIX style.
• Remote, or R, commands are use for the following:
– RLOGIN for remote login
– RSH for remote shell capabilities
– REXEC to execute commands to a remote host
– RMT/RCD to read magnetic tapes or CD-ROMs from remote hosts
• XDM is a network-based graphics window system based on the client/server
application model. It enables a system to display information output from an
application that is running on another system in the network.
•TheFINGER utility is used to display user information for the network.
File Transfer Services
TCP/IP Services includes the following components that let users transfer data
files between local and remote hosts:
File Transfer Protocol (FTP) transfers files between hosts.
Trivial File Transfer Protocol (TFTP) downloads and transfers files. Compaq
TCP/IP Services supports downloading of system image and other information to
client hosts.
Resource Services
Line printer/line printer daemon (LPR/LPD) provides printing services to
local and remote hosts.
TELNET print symbiont (TELNETSYM) provides remote printing services that
enable OpenVMS printing features not available with the LPR/LPD print service.
Network File System (NFS) is a protocol that allows computers to access
remote files as if they were local files, regardless of operating system, hardware
type, or architectural differences between the local and remote systems. This is
accomplished in a client/server environment where specific implementations on
NFS exist on both the client and server machines.
PC-NFS is a daemon that enables access to the NFS server from a PC by providing
authentication services to PC-NFS clients.
1–4 Introducing Compaq TCP/IP Services for OpenVMS