13.8. Using SNMP

Trisul can use SNMP to complement Netflow. You can use it to discover Device names, interface names, interface speeds, plot real time SNMP traffic charts, etc.

13.8.1 Package

To enable SNMP you need to install the following packages on the Trisul-Hub node.


# ubuntu
apt install snmp

# centos/redhat
yum install net-snmp net-snmp-utils

13.8.2 Configuring SNMP

You need to first specify the authentication details for each SNMP device.

Login as user, then select _Netflow > Router and Interfaces

Click on SNMP Settings and enter the SNMP v2 or SNMP v3 parameters.

13.8.3 Resolving names

When you click the Options menu

SNMP Settings Configure SNMPv2 or SNMPv3 parameters.

If the router IP address shown is different from the SNMP Agent IP address then you need to set an additional parameter called snmp.management_ip. See section below on that
SNMP resolve router and interface name Query the SNMP device and automatically assign names to the router and all the interfaces using the “Interface Name” value in the SNMP MIB. Usually this is like Gigabit/1/0/12 etc
SNMP resolve router and interface alias Use “Interface Alias” value in the SNMP MIB. This usually contains a descriptive name for the port. If there is no alias assigned to an interface, Trisul will use the interface name instead
Show Router Description Show the router description in the table. This is the value of sysDescr from the SNMP MIB

When the IP address of the SNMP agent is different

In some environments, the SNMP agent runs on a different IP address than the one shown in the table. If this is the case, then trying to resolve using SNMP via the IP address shown in the routers table will fail. You need to specify a Key Attribute for the router called snmp.management_ip. Follow these steps.

  • First configure SNMPv2 or v3 parameters for the device.
  • Select Options > Key Dashboard
  • Select Assign user label / Edit attributes as shown below

  • Scroll down to the Attributes section and add the following string snmp.management_ip=10.x.x.x replace with actual IP.
  • Update

Now you should be able to resolve the router and inteface names.

13.8.4 Viewing SNMP traffic charts

Against any interface select Options

You get the following options

Live SNMP This brings up a live 5 second updated view of SNMP In/Out traffic chart for that interface.
SNMP Key Dashboard If you have the Trisul SNMP APP installed, Trisul automatically polls all interfaces and maintains historical charts. This takes you to the key dashboard for historical charts.

Live SNMP

Shows a 10-sec updated chart of network traffic on the interface obtained via SNMP. A very useful debugging tool.