basically i am working on http type protocol and in some area i need device data using snmp oid's so how to work for that
To get both HTTP, and SNMP data from a connector you have to ways of achieving this.
You can declare and implement both connections in the protocol which is the recommended way.
There is an example connector here
Protocol Development Guide Companion Files - DataMiner Dojo
Look for the SLC SDF Multiple Connections
The other way is to do an SNMP Get inside of a QAction, but the disadvantage of this is that you wont see traffic via the stream viewer.