Administrator's Guide

Appendix B   The SilverStream SNMP Agent

Simple Network Management Protocol (SNMP) is a protocol used to remotely manage and control nodes on a TCP/IP network. Using SNMP, one workstation running management software can monitor information being collected by routers, servers, and other workstations on the system. This information is used to determine the health and performance of the network. This appendix describes how you can set up and test SNMP to monitor the SilverStream Server.

NOTE   The SilverStream SNMP implementation currently runs on the Windows NT platform only, and does not allow the SNMP service to control the SilverStream Server.

SNMP implementation overview   Top of page

SilverStream implements SNMP using three components:

The SilverStream Extension Agent (AgSNMP35.dll) implements the Windows NT SNMP Application Program Interface (API). The SNMP agent reads the SilverStream Server statistical information from a flat file named AgSNMP.props that is located in the SilverStream\resources directory.

    For a list of available statistics and object identifiers, see SilverStream ID and OIDs.

How the SilverStream components work   Top of page

A SilverStream scheduled business object (AgSNMPGetStats) updates the AgSNMP.props file according to a scheduled interval. When the scheduleReached event fires, the business object gets an instance of the AgiServer object and calls the appropriate methods to build the data for the file. It then gets registry information from the server to determine the SilverStream path and writes the file to the resources directory.

On a GET request, if the update interval has elapsed, the Silverstream Extension Agent updates the MIB data by accessing the registry to get the SilverStream path and reading the AgSNMP.props file in the resources directory. Otherwise, it returns the value that was stored the last time the file was read. If the timestamp in the file is not updated within the given interval, the "Server Responding" status is set to false, indicating a possible problem with the SilverStream Server.

Process flow and terminology   Top of page

The following figure shows how the SilverStream components work within the SNMP framework.

The following terms are used in an SNMP-enabled architecture:

Setting up SNMP for the SilverStream Server    Top of page

This section describes how to set up SNMP as an NT service and run the software. Setting up SNMP involves the following steps:

  1. Installing the software as a service

  2. Installing SilverStream on the server

  3. Enabling the AgSNMPGetStats business object

  4. Testing the program

Installing SNMP as a service   Top of page

If you are installing the SNMP software service on a machine that is currently running the SilverStream Server, first you need to stop the server. In addition, if SilverStream has already been installed, you will need to reinstall SilverStream after installing the service.

To install the SMNP Service:

  1. Log on to NT with administrator privileges.

  2. Select the Network control panel.

  3. Select the Services tab.

  4. Click Add.

  5. Select SNMP Service (you need the NT install CD).

  6. Complete the Agent tab:

    Contact: Name of person or name of machine

    Location: Any descriptive term

  7. Complete the Traps tab (optional):

    Community name: public (optional)

    Trap destinations: IP address of the machine (optional)

  8. After installing the SNMP Service, the following items need to be reinstalled:

Installing SilverStream on the server   Top of page

After you have installed SNMP as a service, use the SilverStream Installation program to install SilverStream on the server to be managed. If you are reinstalling SilverStream, you must stop the SNMP Service first. Otherwise, the install program will not be able to write over the AgSNMPAgent.DLL file.

The SilverStream install process takes care of the required registry key entries and places the agent in the correct location. The required registry entries are as follows:




  Software\SilverStream Software Inc.\SilverStream\version\SNMP\ExtensionAgents\AgSNMPAgent\CurrentVersion 


  HKEY_LOCAL_MACHINE\SOFTWARE\SilverStream Software Inc.\SilverStream\version\SNMP\ExtensionAgents\AgSNMPAgent\CurrentVersion 


  SilverStream Install Directory\bin\AgSNMPversion.dll 

Enabling the scheduled business object   Top of page

In the SilverMaster database, open the business object AgSNMPGetStats and set the Trigger value for Enabled to True. If you want to change the time interval that the business object will fire, you must change it in two places:

Testing the program   Top of page

SilverStream provides a tool that allows you to test the SNMP installation from a DOS prompt. First, open the file SilverStream\bin\SilverSNMPGetStats.bat and change the localhost parameter wherever it appears in the file to the host name on which your SilverStream Server is running. Then follow the next procedure.

To test the SNMP extension agent:

  1. Stop and restart the SNMP Service.

  2. Open a DOS window.

  3. Change to the SilverStream\bin directory

  4. Run the batch file SilverSNMPGetStats. To get a list of available parameters, type:

      SilverSNMPGetStats -? 

SilverStream ID and OIDs   Top of page

The SilverStream Object Identifier is composed of an enterprise ID and the OID identifying each Managed Object (MIB). You will need the following information to set up access to the SilverStream Server OIDs from your SNMP Management node:

The following are the SilverStream OIDs. When accessing MIB data using SNMPTool.exe, you must precede the OID with a period.

Statistic Description


Host Name OID

Server Revision OID

Server Start Time OID

Data Time Snapshot OID

Maximum Requested URL OID

Minimum Requested URL OID

Server Load OID

Free Thread Count OID

Idle Thread Count OID

Total Thread Count OID

Hit Count OID

Mean Request Time OID

Max Request Time OID

Min Request Time OID

Emitted Bytes OID

Free Memory OID

Total Memory OID

Garbage Collection Count OID

Idle Sessions OID

Total Sessions OID

Server Responding OID

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