1 ITC242 – Introduction to Data Communications Week 12 Topic 18 Chapter 19 Network Management

2 Last Week Network Security Describe the most important security threats faced by distributed data processing Compare conventional and public-key encryption Discuss the application of encryption to network security Discuss the use of IPSec to create a virtual private network

3 Topic 18 – Network Management Learning Objectives Describe the key requirements that a network management system should satisfy Describe an overview of the architecture and key elements of a network management system. Describe SNMP and the difference between versions 1,2 and 3

4 ISO management Functional Areas Fault management Accounting management Configuration and name management Performance management Security management

5 Fault Management A fault is an abnormal condition that requires management attention (or action) to repair A fault is usually indicated by failure to operate correctly or by excessive errors Examples: communication link is physically cut; no signals can get through Users expect quick and reliable resolution

6 Responding to Faults When faults occur, it is critical to quickly: –Determine exactly where the fault is –Isolate the rest of the network from the failure so that it can continue to function without interference –Reconfigure or modify the network to minimize the effect of removing the failed component(s) –Repair or replace the failed components to restore the network to its initial state

7 User Requirements for Fault Management Tolerant of occasional outages, but expect speedy resolution Requires rapid and reliable fault detection and diagnostic management functions Impact and duration of faults can be minimized with redundancy Good communication with users about outages and faults is critical

8 Accounting Management Overview: Internal charging for the use of network services. Also used for monitoring the use of and planning network services. User Requirements: What information is to be recorded where? Privacy considerations.

9 Configuration Management Concerned with: –initializing a network and gracefully shutting down part or all of the network –maintaining, adding, and updating the relationships among components and the status of components themselves during network operation Operations on certain components should be able to be performed unattended Network manager needs the capability to change the connectivity of network components Users should be notified of configuration changes

10 Performance Management What is the level of capacity utilization? Is there excessive traffic? Has throughput been reduced to unacceptable levels? Are there bottlenecks? Is response time increasing? Network managers need performance statistics to help them plan, manage, and maintain large networks

11 Security Management Concerned with –generating, distributing, and storing encryption keys –monitoring and controlling access to networks –access to all or part of the network management information –collection, storage, and examination of audit records and security logs Provides facilities for protection of network resources and user information Network security facilities should be available for authorized users only

12 Network Management Systems Collection of tools for network monitoring and control, integrated in these ways: –A single user-friendly operator interface for performing most or all network management tasks –A minimal amount of separate equipment Consists of incremental hardware and software additions implemented among existing network components Designed to view the entire network as a unified architecture, and provide regular feedback of status information to the network control center

13 Network Management System Architecture

14 Components of the NMS Nodes run the Network Management Entity (NME) software Network control host or manager runs the Network Management Application (NMA) Other nodes are considered agents

15 Network Management Entity Collection of software contained in each network node, devoted to the network management task Performs the following tasks: –Collect statistics on communications and network- related activities. –Store statistics locally –Respond to commands from the network control center –Send messages to network control center when local conditions undergo a significant change

16 Simple Network Management Protocol (SNMP) Originally developed for use as a network management tool for networks and internetworks operating TCP/IP. A collection of specifications that include the protocol itself, the definition of a database, and associated concepts. Network Management Model –Management station –Agent –Management information base –Network management protocol

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18 Simple Network Management Protocol (SNMP) Management station: a standalone device: – a set of management applications: data analysis, faulty recovery and so on – A user interface: monitor and control the network –A database: network management –Translate the network manger’s requirements into actual monitoring and control of remote elements in the network Agent: key platforms( hosts, bridges, routers) +agent software Management information base (MIB): a collection of objects, which are data variables that represent the aspects of the managed agent. Network Management protocol: for linking the management station and agents

19 SNMPv1 Configuration

20 Role of SNMPv1

21 SNMPv2 Released in 1992, revised in 1996 Addressed functional deficiencies in SNMP Accommodates decentralized network management Improves efficiency of data transfer

22 Elements of SNMPv2 Each "player" in the network management system maintains local database of network management information (MIB) Standard defines information structure and allowable data types (SMI) At least one system must be responsible for network management; others act as agents Information exchanged using simple request/respond protocol, usually running over UDP

23 Structure of Management Information (SMI) Defines framework within which a MIB can be defined and constructed –data types that can be stored –formal technique for defining objects and tables of objects –scheme for associating a unique identifier with each actual object in a system Emphasis on simplicity and extensibility

24 SNMPv3 Released in 1998, addressed security deficiencies in SNMP and SNMPv2 Does not provide a complete SNMP capability; defines an overall SNMP architecture and a set of security capabilities for use with SNMPv2

25 Review Key requirements that a network management system should satisfy The architecture and key elements of a network management system. SNMP and the difference between versions 1,2 and 3