Before getting started with Agentuino it is recommended to familiarize yourself with Simple Network Management Protocol.

http://en.wikipedia.org/wiki/Simple_Network_Management_Protocol

To understand the low level structure of an SNMP packet, read up on ASN.1 and the BER encoding of ASN.1 . Section 8 of RFC1906, which places a few additional SNMP specific constraints on BER encoding, will also be of interest