RL-ARM User's Guide

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RL-ARM User's Guide

RL-RTX RL-FlashFS RL-TCPnet TCP Socket Opening TCP Connection TCP Active Open TCP Passive Open Sending TCP Data Example for Sending Data Multiple TCP Connections UDP Socket Opening UDP Connection Sending UDP Data When DHCP Enabled When ARP Cache Empty Example for Sending Data IP Multicasting Multiple UDP Connections Configuring TCPnet Static Configuration System Definitions Ethernet Network Interface PPP Network Interface SLIP Interface UDP Socket TCP Socket BSD Socket HTTP Server Telnet Server TFTP Server FTP Server DNS Client SMTP Client SNMP Agent Runtime Configuration Library Files Using RL-TCPnet Stand Alone With RTX Kernel Applications HTTP Web Server Script Language CGI Functions Ajax Support Using XML XML Example How it works SOAP Support SOAP Interface Large POST Messages Web Pages Default Page Error Pages Web on SD Card Web Update File System Interface Http Caching How it works Internal Web External Web Using RAM File System FCARM File Converter PRINT Directive NOPRINT Directive PAGEWIDTH Directive PAGELENGTH Directive ROOT Directive Telnet Server Command Line Interface Sending Reply Message Short Reply Long Reply Continuous Screen Update TFTP Server File System Interface FTP Server File System Interface Supported Commands SMTP Client SNMP Agent MIB Database MIB Interface MIB Entry MIB Table DNS Resolver Starting DNS Device Drivers Ethernet Driver Interrupt Mode Modem Driver Serial Driver Using Serial Link Cable Connection Modem Connection Windows Dial-up Add Direct Serial Link New Dial-up Connection Configure PPP Dial-up Configure SLIP Dial-up Debugging Enabling Debug Debug Level Redirecting Output Function Overview BSD Routines CGI Routines Ethernet Routines Error Function FTP Routines HTTP Routines IGMP Routines Miscellaneous Routines Modem Routines PPP Routines Serial Routines SLIP Routines SMTP Routines SNMP Routines System Functions TCP Routines Telnet Routines TFTP Routines UDP Routines RL-CAN RL-USB Example Programs Library Reference Appendix

SNMP Agent

Simple Network Management Protocol (SNMP) is mainly used in network management systems to monitor network-attached devices for conditions that warrant administrative attention. It is the most popular network management protocol in the TCP/IP protocol suite.

SNMP is a simple request/response protocol that communicates management information between two types of SNMP software entities: SNMP managers and SNMP agents.

SNMP Community and Functions

In summary, the SNMP Management program performs the following operations:

  • The GET operation receives a specific value about a managed object, such as the available hard disk space from the agent's MIB.
  • The GET-NEXT operation returns the "next" value by traversing the MIB tree of managed object variables.
  • The SET operation changes the value of a managed object's variable. Only variables whose object definition allows read/write access can be changed.
  • The TRAP operation sends a message to the Management Station when a change occurs in a managed object, and that change is important enough to send an alert message.

The SNMP Agent validates each request from an SNMP manager before responding to the request, by verifying that the manager belongs to an SNMP community with access priviliges to the agent. An SNMP community is a logical relationship between an SNMP agent and one or more SNMP managers. The community has a name, and all members of a community have the same access privileges: either read-only or read-write.

An Embedded SNMP Agent is an optimized and compact implementation for embedded systems. Currently it implements SNMP version 1.

 

  • In order to use an Embedded SNMP Agent, you must enable and configure it in the configuration file.