The fields of an SNMP PDU (Protocol Data Unit) are:
1. Version: The version of SNMP protocol being used.
2. Community: The identifier used for authentication purposes.
3. Type: Specifies the type of PDU (Get, Set, Response, etc.).
4. Request ID: Unique identifier for each SNMP request message.
5. Error Status: Indicates whether an error occurred during the request.
6. Error Index: Indicates the position of the error in case of multiple requests.
7. Variable Bindings: A list of objects requested or set by the SNMP manager or agent.
