Simple Network Management Protocol

1. Simple Network Management Protocol CIT 443 – Enterprise Network Management

2. Simple Network Management Protocol • The features of SNMP which make it popular: • Its design is simple, making it is easier to implement on networks of any size • Its simple design makes it easy for a user to program variables they would like to have monitored. • It is popular and extensible, • a device manufacturer can easily add new registers for monitoring

3. SNMP Architecture and Model Network Management Organization Model Information Model Communication Model Functional Model Similar to OSI Model

4. SNMPModel • Organization Model • Relationship between network element, agent, and manager • Hierarchical architecture • Information Model • Uses ASN.1 syntax • SMI (Structure of Management Information) • MIB ( Management Information Base) • Communication Model • Transfer syntax • SNMP over TCP/IP • Communication services addressed by messages • Security framework community-based model

5. SNMP Architecture and Model Network Management Organization Model Information Model Communication Model Functional Model

6. Two-Tier Organization Model

7. Three-Tier Organization Model: RMON

8. Three-Tier Organization Model:Proxy Server

9. SNMP Messages • Get-Request • Sent by manager requesting specific data from agent • Get-Next-Request • Sent by manager requesting data on the next MO to the one specified • Set-Request • Initializes or changes the value of network element • Get-Response • Agent responds with data for get and set requests from the manager • Trap • Alarm generated by an agent

10. SNMP Architecture and Model Network Management Organization Model Information Model Communication Model Functional Model ASN.1 Format RFCs Define Specifics

11. Managed Object: Multiple Instances

12. Object Naming • Uniquely defined by • DESCRIPTOR AND • OBJECT IDENTIFIER

13. Management Information Base • Hierarchy of information about a device • Think of a MIB as a simple database • Uniquely identifies specific information on a specific device • Object Type • Name • Allowable Operations

14. Structure of Management Information (SMI) • Defines standard unique names for objects • Defines standard formats for objects for use in MIB • Length • Data type • etc

15. MIB II

16. Chapter 4 Internet Subnodes

17. Chapter 4 Private MIB Example

18. SNMP Architecture and Model Network Management Organization Model Information Model Communication Model Functional Model

19. SNMP Communication

20. Simple Network Management Protocol (SNMP) The features of SNMP which made it popular:- • Its design is simple, hence it is easy to implement on a large network • Its simple design makes it easy for a user to program variables they would like to have monitored. • It is popular and extensible, a device manufacturer can easily add new registers for monitoring

21. SNMP V2 • Enhancements of SNMPv2: • Expanded data types (e.g., 64 bit counter) • Improved efficiency and performance (get-bulk operator) • Confirmed event notification & inter NMS communication (inform operator) • Richer error handling (errors and exceptions)

22. SNMP V2 • SNMP Interoperability:- • As presently specified, SNMPv2 is incompatible with SNMPv1 in two key areas: • message formats • protocol operations. • SNMPv2 messages use different header and protocol data unit (PDU) formats than SNMPv1 messages. SNMPv2 also uses two protocol operations that are not specified in SNMPv1.

23. SNMP V2 • Bilingual Network-Management System: Bilingual SNMPv2 network-management systems support both SNMPv1 and SNMPv2. To support this dual-management environment, a management application in the bilingual NMS must contact an agent. The NMS then examines information stored in a local database to determine whether the agent supports SNMPv1 or SNMPv2. Based on the information in the database, the NMS communicates with the agent using the appropriate version of SNMP.

24. SNMP V2 However, the SNMPv2 Framework, as described in these documents, is incomplete in that it does not meet the original design goals of the SNMPv2 project. The unmet goals included provision of security and administration with authentication, privacy authorization, access control and suitable remote configuration and administration capabilities for these features. .

25. SNMPv2 SECURITY: WHAT HAPPENED? • APRIL 1993: • Standard Proposed w/ 4 Editors • Security Based on PARTIES • 1st prototypes appeared shortly thereafter • JUNE 1995: • PROPOSED STANDARD REJECTED BY TWO OF THE ORIGINAL EDITORS! • AUGUST 1995: • Agreement that Party-based Model is too complex • NEW PROPOSALS: • SNMPv2C: COMMUNITY BASED • SNMPv2U: USER BASED • ... • 1997: • SNMPv3 Working Group Formed • With ALL NEW Editors

26. SNMP v3 • The SNMPv3 Management Framework, addresses the significant deficiencies of v2. • addressing the missing links: • security • administration • in the process made invaluable contributions to the state-of-the-art of management

27. SNMPv3 ARCHITECTURE SNMP ENTITY SNMP APPLICATIONS NOTIFICATION RECEIVER PROXY FORWARDER OTHER COMMAND NOTIFICATION ORIGINATOR COMMAND RESPONDER OTHER GENERATOR SNMP Manager SNMP Agent SNMP ENGINE MESSAGE PROCESSING SECURITY ACCESS CONTROL DISPATCHER SUBSYSTEM SUBSYSTEM SUBSYSTEM

28. SNMPv3 ARCHITECTURE: MANAGER

29. USM: SECURITY THREATS

30. Questions?