Introduction

Acronyms first !

SMI

Structure of Management Information, describes how managed Objects contained in the MIB are defined.

SMIV1 is described in the following RFC: RFC1155, RFC1212, RFC1215.

BER

Basic Encoding Rules, describes a method for encoding values of each SMI types as a string of bytes.

SNMP

Simple Network Management Protocol, supports a few operations: SET, GET, GET-NEXT and TRAP to manage object.

SNMPV1 is defined in RFC1157.

MIB

Management Information Base, a collection of objects representing resources to manage.

SNMP framework

• A data definition language (SMI)
• Definitions of managed objects (MIB)
• A protocol definition (SNMP)
• Security and administration (with SNMPV1 we talk about community).

SNMP is still evolving. For a better understanding of the history of this framework, you should consider reading RFC 2570 (Introduction to SNMPV3).

SCK only deals with SMIV1 and SNMPV1.

What means SCK ?

SCK is the Snmp Construction Kit, a framework designed to allow anyone to build network management applications.
SCK is available under the GNU GPL.

Construction ?

import java.net.*;
import java.io.*;
import sck.*;

public class TrapReceiver{
  private final static int trapPort = 162;

  public static void main(String[] argv){
    try {
      DatagramSocket sock = new DatagramSocket(trapPort);
      while (true){
                byte[] b = new byte[1024];
        DatagramPacket p = new DatagramPacket(b,b.length);

        sock.receive(p); // block 

        ByteArrayInputStream ber = new ByteArrayInputStream(b,1,p.getLength()-1); // without tag, like all smi object !
        Message m = new Message(ber);

        System.out.println("Trap received at : " + new java.util.Date());
        StringBuffer buf = new StringBuffer();
        m.println("",buf);
        System.out.println(buf);
      }
    } 
    catch (Exception e){
        System.err.println(e);
        System.exit(1);
    }
  }
}

You can now go to the Repository to see more examples or browse documentation: look at the SCK api doc and don't forget the class diagram.

Standards.

RFC 1155

Stucture and identification of Management Information for tcp/ip based networks.

RFC 1212

Concise Mib definitions.

RFC 1215

A convention for defining traps for use with SNMP

RFC 1157

Simple Network Management Protocol.

How to contact the author ?