SNMP – Simple Network Management Protocol
When using SNMP, typically one or more managers to monitor a group of manged devices.
SNMP network consists of 3 components:
- Managed Device
- Agent – software that runs on the managed devices, contains information of the managed device and translates it to and from SNMP forms
- Network Management System (NMS) – software running on the managers that monitors and control managed devices on the network.
There are 3 Versions – SNMPv1, SNMPv2, SNMPv3
SNMPv1
- Initial implementation
- Contains 5 core PDUs( protocol data units)
- GetRequest – Sent from manager to agent to retrieve the value of a variable or set of variables
- SetRequest – Sent from manager to agent to request to change the value of a variable or set of variables
- GetNextRequest – Sent from manager to agent to discover any available variables and their values.
- Response – Sent from agent to manager to return variable bindings and acknowledge GetRequest, SetRequest and GetNextRequest messages
- Trap – Sent from agent to manager to notify the manager about something.
SNMPv2
- Revises v1 and improves performance, security, confidentiality and manager-to-manager communication.
- Adds to more PDUs
- GetBulkRequest – Sent from manager to agent to request multiple iterations of the GetNextRequest.
- InformRequest – Sent from manager to manager, or from agent to manager. Receiver responds with an acknowledge.
SNMPv2 is incompatible with SNMPv1 with regards to message formats and protocol operations.
SNMPv3
- Adds security and remote configuration enhancements.
- Provides security through confidentiality, integrity, and authentication.
SNMP implementations often support multiple versions: typically SNMPv1, SNMPv2c*, and SNMPv3
* SNMPv2c – Community-Based Simple Network Management Protocol version, uses same security model as SNMPv1.
For more information about SNMP please to some of the following links:
http://en.wikipedia.org/wiki/Simple_Network_Management_Protocol
http://www.rane.com/note161.html
http://www.cuddletech.com/articles/snmp/