Fundamentals of Network Management

1. Fundamentals of Network Management

2. Network Management Standards • OSI • Common Management Information Protocol (CMIP) • International standard (ISO / OSI) • Management of data comm. Network LAN and WAN • Deals with all 7 layers • Most complete • Object oriented representation • Well structured and layered • Consumes large resources in implementation • Internet • Simple Network Management Protocol (SNMP) • Industry standard (IETF) • Originally intended for management of Internet components, currently adopted for WAN and telecom systems. • Easy to implement • Most widely implemented NM standard. • Lacks advanced functionality (compared to CMIP)

3. Network Management Standards (…) • Telecommunication Management Network (TMN) • International standard of the ITU-T • Management of telecom networks • Based on the OSI network management framework • Addresses both network, administrative, and business aspects of management. • IEEE • Addresses LAN and MAN management. • Deals with the first 2 layers. • Web-based Management • Web-based Enterprise Management (WBEM) • Java Management Application Program Interface (JMAPI)

4. Management Architecture • This architecture is used for both OSI and SNMP-based management • Consists of a number of models

5. OSI Models • Organization • Network management components • Functions of components • Relationships • Information • Structure of Management Information (SMI) • Syntax and semantics • Management Information Base (MIB) • Organization of management information • Communication • Transfer syntax with bi-directional messages • Transfer structure (PDU) • Functions • Application functions • Configure components • Monitor components • Measure performance • Secure information • Usage accounting

6. SNMP Architecture and Models • Organization • Same as OSI model • Information • Same as OSI, but scalar • Communication • Messages less complex than OSI and unidirectional • Transfer structure (PDU) • Functions • Application functions • Operations • Administration • Security

7. Organizational Model • Manager • Sends requests to agents • Monitors alarms • Houses applications • Provides user interface • Agent • Gathers information from objects • Configures parameters of objects • Responds to managers’ requests • Generates alarms and sends them to mangers • Managed object • Network element that is managed • Houses management agent • All objects are not managed / manageable

8. Managed object Manage objects can be Network elements (hardware, system) hubs, bridges, routers, transmission facilities Software (non-physical) programs, algorithms Administrative information contact person, name of group of objects (IP group) Houses SNMP management agent Objects are classified into managed/unmanaged Managed object has a running management agent Manager MDB Managed objects Unmanaged objects MDB Management Database Agent process Two-Tier Network Management Organization Model Organization Model

9. Management Station (Manager) Interface for network managers to monitor and control the network Contains management applications (data analysis, fault recovery, etc.) Translation capabilities from manager’s requirements into actual monitoring and control of remote elements Contains DB of information extracted from MIBs of all the managed entities in the Network Manager MDB Managed objects Unmanaged objects MDB Management Database Agent process Two-Tier Network Management Organization Model Organization Model

10. Management Agent Gathers information from objects Configures parameters of objects (e.g., enable/disable a router port, shut down a port on a hub, etc.) Responds to requests for information and actions from managers Generates alarms and sends them to managers Manager MDB Managed objects Unmanaged objects MDB Management Database Agent process Two-Tier Network Management Organization Model Organization Model

11. Middle layer plays the dual role Agent to the top-level manager Manager to the managed objects collects, processes and stores data locally Performs statistical operation on the data and passes it to top level manager The intermediate system could be at a local site and passes info. to a remote site. Example of middle level: Remote monitoring agent (RMON) Manager MDB Agent / Manager MDB Managed objects MDB Management Database Agent process Three-Tier Network Management Organization Model Organization Model

12. Different network domains, each managed locally Agent NMS manages the domain MoM presents integrated view of domains Domain may be geographical, administrative, vendor-specific products, etc. MoM Manager of Managers MoM NMS Network Management System MDB Agent Agent Agent NMS Agent NMS MDB MDB Manager Manager Managed objects Managed objects Organization Model

13. Peer NMSs Dual Role of Management Process

14. Resources are represented as objects (or data variables) Collection of objects is a MIB (more later) A manager performs monitoring by retrieving the value of MIB objects A manager causes an action to take place or changes the configuration settings by modifying values of specific variables SNMP MIB MANAGER AGENT Communication Model

15. Management stations and agents are linked by a network management protocol SNMP is used for the management of TCP/IP networks Get: manager or management station can retrieve the value of objects at the agent Set: set the values of objects at the agent Trap: agent notifies manager on significant events SNMP MIB MANAGER AGENT Communication Model

16. Protocol Architecture -SNMP uses UDP port 161 - connection-less (e.g., Ethernet, X.25, ATM) Interprets SNMP messages and controls the agent’s MIB

17. Management data is communicated between agent and manager as well as between managers Three aspects: Transport medium of message exchange (transport protocol) Message format (application protocol) Actual message (commands and responses) Operations / Requests Manager Responses Agent Notifications / Network Elements Applications Traps Managed Objects Management Message Communication Model Communication Model

18. Application manages object Central MIB GetRequest GetNextRequest SetRequest GetResponse Trap GetRequest GetNextRequest SetRequest GetResponse Trap SNMP Manager SNMP Agent SNMP Messages UDP UDP IP IP Network Layer 1 & 2 Layer 1 & 2 Communication Model SNMP managedobjects Managementapplication

19. SNMP encourages the manager to use trap-directed polling A manager may be responsible for a large number agents, each maintains a large number of managed objects It is impractical to regularly poll all agents for all their readable objects (management overhead on the network may be very excessive!) managing entity data data data data data agent agent agent agent Trap-Directed Polling managing entity managed device network management protocol managed device managed device managed device

20. Initially a manager may poll all the agents for some key information e.g., interface characteristics (# pckts in/out, etc..) Then, each agent is responsible for notifying (through trap messages) the manager of any unusual event e.g., high pckt drop rate at some interface managing entity data data data data data agent agent agent agent Trap-Directed Polling managing entity managed device network management protocol managed device managed device managed device

21. The representation of objects and information relevant to their management This information is usually communicated between agents and management processes SMI(Structure of Management Information) defines the syntax and semantics of management information stored in MIB (Management Information Base) Information Model ExamplesysDescr: { system 1 }Syntax: OCTET STRINGDefinition: "A textual description of the entity. "Access: read-onlyStatus: mandatory MIB • Contains information about objects • Organized by grouping of related objects • Defines relationship between objects • Agent MIB vs. Manager MIB • MIB Agent: local information • MIB Manager: info. on all network components

22. Information Model • MDB physical database; e.g.. Oracle • Contains measured or administratively configured values of NEs • MIB virtual database; schema compiled into management software • Info necessary for processes to exchange info. (e.g., #ports/hub) • A NMS can automatically discover (periodic broadcast of PING messages) a managed object, such as a hub, when added to the network • Once detected, its information (e.g., address, number of ports, etc.) is added to MDB • MIB does not need to be updated if another hub from same vendor already exist

23. itu iso iso-itu 0 1 2 Root org 3 Level 1 dod Level 2 6 Level 3 internet 1 Management Information Tree OSI Management Information Tree Management Information Tree • Designation of objects: • iso 1 • org 1.3 • dod 1.3.6 • internet 1.3.6.1 • Both Internet and OSI define objects uniquely by a tree structure • Each managed object occupies a node in the tree underneath the root Standard organizations: define management of objects under them Managed Objects

24. Access: Object Type: Object ID Access and Descriptor privilege circle Status : Implementation requirements Syntax : Definition : model of object Semantics - textual description Internet Perspective Object Type and Instance object ID unique ID and descriptor and name for the object syntax used to model the object access access privilege to a managed object (read-only, etc) status implementation requirements (e.g., optional or mandatory) definition textual description of the semantics of object type

25. Notifications : Notify changes in attribute values Object Class: Elliptical object Circular Object Class: object Behavior Operations: Push Attributes: : Attributes: ellipse, dimension circle, dimension OSI Perspective Object Type and Instance object classmanaged object attributes attributes visible at its boundary operations access operations that can be applied to it behavior behavior exhibited by it in response to an operation Notifications notifications emitted by the object

26. Object Type and Instance

27. Functional Model • Configuration management • Set and change network configuration and component parameters • Set up alarm thresholds • Fault management • Detection and isolation of failures in network • Trouble ticket administration • Performance management • Monitor performance of network • Security management • Authentication • Authorization • Encryption • Accounting management • Functional accounting of network usage