i want to use splunk and SNMP to read data from the network switch ...Do i need SNMP modular input?
The SNMP Modular Input can be used to poll SNMP attributes and catch SNMP traps from your network switch. So this data can give you operational visibility into the status and performance metrics of the switch.
When you say "read data" , if you are meaning you want to sniff wire data , then you will want to look at Splunk App for Stream
Yes, if you want to Poll or Collect directly into Splunk.
Splunk doesnt support SNMP out of the box. The SNMP modular input is a input that can poll and collect SNMP off devices. I recommend reading the documentation with the APP from:
https://splunkbase.splunk.com/app/1537/
There is quite a bit of integration work required from the OS level for this to work.