R2511-HP MSR Router Series Terminal Access Configuration Guide(V5)

Configuring terminal access

NOTE:

The HP MSR900, and MSR93X (except the JG514A, JG515A and JG531A) routers do not support

interface modules and thus cannot provide terminal access through an asynchronous serial port module.

Overview

Terminal access enables a terminal to use an asynchronous interface to access a front-end processor (FEP)

or another terminal through a router.

The following types of network devices are used in terminal access:

• Terminal—A character device that is generally connected to another device through a serial

interface cable. A user inputs characters by using the terminal keyboard. Then the characters are

transferred to another device through the serial interface cable. After processing the characters, the

device returns the result to the terminal, which displays the result on its screen.

• Initiator—Sends a connection request and serves as the client of the connection. Generally, a router

is used as an initiator

• Receiver—Responds to a connection request and serves as the server of the connection. A receiver

can be an FEP or a router. An FEP is a system installed with an application program for banking,

postal service, taxation, customs, civil aviation, and so on. A FEP can be a Unix server or a Linux

server.

• Relay server—Provides similar functions as a receiver, except that the relay server is not directly

connected to terminals. Instead, the relay server is connected to multiple initiators simultaneously

and manages them in different forwarding groups according to the listening port number. Data

received from an initiator is forwarded to other initiators in the same group.

After a connection is established, the router, functioning as either the terminal access initiator or receiver,

can transparently transmit the data from the terminal to the peer over the connection. Transparent means

that no manual or extra operation is required.

Connections between an initiator and a receiver can use either TCP or UDP.

Terminal access types

The following types of terminal access are used in different applications:

• True type terminal (TTY) access

• Telnet terminal access

• Enhanced Telnet (ETelnet) terminal access

• Secure Shell (SSH) terminal access

• Remote terminal connection (RTC) access

TTY terminal access, Telnet terminal access, ETelnet terminal access, and SSH terminal access are used

to help implement services between a terminal and an FEP, with a router as the initiator and the FEP as

the receiver. The difference between them is their method of data encryption and their way of