Discovering the Network in NNM v7.5x

After we have NNM installed and running, we need to add devices to NNM for monitoring. In this post we shall see the basics of the discovery process in NNM.

Discovering the network in NNM can be done automatically or in a controlled manner, i.e. > Automatic Discovery 
> Manual Discovery
Automatic discovery is not advised unless the environment is very small. 'netmon' process is responsible for discovery of the network devices.

Manual Discovery in NNM is done via  

1)      Seed File

2)     loadhosts  program

Seed File Procedure

The various steps involved in this procedure are :

Step 1:- Create an ASCII file which will contain the IP Address / Hostname of the devices, that are to be included in the map.

A Sample seedfile could look like

############################################################

192.24.25.26

192.34.25.26       #Gateway 1*

Railey.johs.com

Sydney1.johs.com   # Sydney router

###########################################################

(#) anything after this is interpreted by netmon as comments included by the administrator.

(*) Include gateways in seeds to get the maximum devices discovered, as gateways maintain largest ARP Tables

Step 2:- Modify the netmon.lrf file 
/etc/opt/OV/share/lrf/netmon.lrf
(Ensure a backup of netmon.lrf is taken before doing this modification)

Search for this text

netmon:netmon:

OVs_YES_START:ovtopmd,pmd,ovwdb:-P:OVs_WELL_BEHAVED: 15:

            
After –P insert –s (location where seedfile is actually stored)

Assume seed file is stored in /usr/john/seed.txt  ( "C:\NNMfiles\seedone" in Windows )

netmon:netmon:

OVs_YES_START:ovtopmd,pmd,ovwdb:-P -s \usr\john\seed.txt":OVs_WELL_BEHAVED:15:

OR
netmon:netmon:
OVs_YES_START:ovtopmd,pmd,ovwdb:-P -s "C\:\NNMfiles\seedone":OVs_WELL_BEHAVED:15:

           

Step 3:- Save the netmon.lrf and stop the netmon service using  command  
ovstop netmon 

Step 4:- To update the ovsuf with netmon configuration change use ovaddobj command

ovaddobj $OV_LRF/netmon.lrf               # UNIX
ovaddobj install_dir\lrf\netmon.lrf       # WINDOWS

Step 5:- Restart the netmon service using ovstart
ovstart netmon

NNM will then use the seedfile and will discover the devices mentioned .

loadhosts Procedure

               
loadhosts procedure is used to place the devices directly in the topology map and to reduce the network traffic of discovering the devices, devices in this procedure are immediately added in the database and placed in the map.

The steps involved are

Step 1:- Create a ASCII file containing the IP address or hostname of the devices to be added, each device is to be specified in separate line

A sample loadhosts file

##################################################################

192.3.4.89

192.5.3.4

routerone.johns.com

 ##############################################################################

Step 2:- On the command prompt type
#>      loadhosts –m <subnet mask> <filename>
#> loadhosts -m 255.255.248.0 /usr/john/hosts.txt