Using SNMP for Terminal Management

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SNMP Overview

SNMP is an industry-standard set of protocols for network management in TCP/IP network environments. It provides mechanisms for monitoring and controlling terminals from a central location.

Using SNMP from a network host, you can:

Display or modify the values of all terminal configuration parameters
Obtain additional information, including network traffic levels, network error levels, basic system and network configuration data, and the state of the font cache
Configure network-oriented timers
Remotely reset NCD terminals

SNMP Components

SNMP consists of four interrelated parts:

An SNMP agent in the X server
SNMP manager software, located on a host computer and available from a number of vendors. Most management software includes utilities for collecting information from agents. Some management software also includes utilities for generating reports and setting variables.
MIB (Management Information Base), information defined by standard variables mandated in RFC 1212, plus variables added by NCD. The NCDware distribution includes two versions of the MIB:
- The combined NCDware MIB and MIB II file, with the following name and default location: /usr/lib/X11/ncd/snmp/mib.txt
- The new, updated NCDware-only MIB file that includes SNMP variables for all NCD remote configuration parameters, with the following name and default location: /usr/lib/X11/ncd/snmp/mib.my
The protocol that connects the manager with agents

The NCDware distribution also includes two utilities: ncdreset(1) for remotely resetting terminals and ncdquery(1) for displaying the values of certain NCD-specific variables.

How SNMP Works

NCD terminals respond to queries from hosts running SNMP management software. Manager hosts have read/write access; monitor hosts have read-only access; and trap monitors receive information about significant events.

The SNMP manager initiates information gathering by sending a request for information to the SNMP agent in the terminal. When the request is received, the agent collects data as specified in the MIB and sends it to the manager. Using SNMP utilities, the system administrator can read or write variables.

NCDware provides an access control mechanism that you can use to prevent read/write or read-only access to the SNMP agent from outside the terminal or restrict access to a specified list of hosts. Both levels of access are further controlled by passwords called community names.

MIB Contents

All of the mandatory variables are included in NCD's SNMP agent except for the ifAdminStatus variable. Read-only access is provided for this variable, but write access can cause security problems and is not necessary on NCD terminals, which have only one network interface.

The NCDware MIB file contains SNMP variables for all NCD configuration parameters. Each configuration parameter has a unique SNMP variable name and path; for example, the SNMP variable name and path for the boot-desired-source parameter are: ncdBootDesiredSource and ncdBoot 5.

The SNMP variable name and path for each parameter are listed in the Remote Configuration Parameter Quick Reference.

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Copyright © 1997, NCD Inc. All rights reserved.