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SNMPv3: Simple Network Management Protocol version 3

SNMP is the protocol developed to manage nodes (servers, workstations, routers, switches and hubs etc.) on an IP network. Currently, there are three versions of SNMP defined: SNMP v1 , SNMP v2 and SNMPv3. In this document, we provide information primarily for SNMPv3.

SNMP Version 3 (SNMPv3) adds security and remote configuration capabilities to the previous versions. The SNMPv3 architecture introduces the User-based Security Model (USM) for message security and the View-based Access Control Model (VACM) for access control. The architecture supports the concurrent use of different security, access control, and message processing models. More specifically:

Security

authentication and privacy

authorization and access control 

Administrative Framework

naming of entities

people and policies

usernames and key management

notification destinations

proxy relationships

remotely configurable via SNMP operations

SNMPv3 also introduces the ability to dynamically configure the SNMP agent using SNMP SET commands against the MIB objects that represent the agent's configuration. This dynamic configuration support enables addition, deletion, and modification of configuration entries either locally or remotely.

For information on SNMP , SNMPv1 and SNMPv2 , please check the corresponding pages. 




Protocol Structure - SNMPv3 Simple Network Management Protocol version 3SNMPv3 message format:

Msg Processed by MPM (Msg Processing Model)

Version

ID

Msg Size

Msg Flag

Security Model

Msg Processed by USM (User Security Module)

Authoritative

Engin ID

Authoritative

Boots

Authoritative

Engine Time

User name

Authentication parameters

Privacy Parameter

 Scoped PDU

Context engine ID

Context name

PDU

  • Version --For SNMPv3 it is 3.
  • ID --A unique identifier used between two SNMP entities to coordinate request and response messages
  • Msg Size -- Maximum size of a message in octets supported by the sender of the message
  • Msg Flags --An octet string containing three flags in the least significant three bits: reportableFlag, privFlag, authFlag.
  • Security Model --An identifier to indicate which security model was used by the sender and therefore which security model must be used by the receiver to process this message.
  • AuthoritativeEngineID -- The snmpEngineID of the authoritative SNMP engine involved in the exchange of this message. Thus, this value refers to the source for a Trap, Response, or Report, and to the destination for a Get, GetNext, GetBulk, Set, or Inform.
  • AuthoritativeEngineBoots --The snmpEngineBoots value of the authoritative SNMP engine involved in the exchange of this message.
  • AuthoritativeEngineTime -- The snmpEngineTime value of the authoritative SNMP engine involved in the exchange of this message.
  • User Name --The user (principal) on whose behalf the message is being exchanged.
  • AuthenticationParameters -- Null if authentication is not being used for this exchange. Otherwise, this is an authentication parameter.
  • PrivacyParameters -- Null if privacy is not being used for this exchange. Otherwise, this is a privacy parameter.
  • PDU (Protocol Data Unit)-- The PDU types for SNMPv3 are the same as the SNMPv2.


Related Protocols
SNMP , SNMPv1 , SNMPv2 , SNMPv3 , UDP , RMON , SMI, OIDs

Sponsor Source

SNMPv3 is defined by IETF (http://www.ietf.org ) in RFC 3411 plus a group of supporting RFCs shown in the reference links.

Reference

http://www.javvin.com/protocol/rfc3410.pdf : Introduction and Applicability Statements for Internet Standard Management Framework
http://www.javvin.com/protocol/rfc3411.pdf : Architecture for Describing SNMP Frameworks
http://www.javvin.com/protocol/rfc3412.pdf : Message Processing and Dispatching for the SNMP
http://www.javvin.com/protocol/rfc3413.pdf : SNMP Applications
http://www.javvin.com/protocol/rfc3414.pdf : User-based Security Model (USM) for SNMPv3
http://www.javvin.com/protocol/rfc3415.pdf : View-based Access Control Model for the SNMP
http://www.javvin.com/protocol/rfc3584.pdf : Coexistence between SNMP v1, v2 and v3