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 ManagementProtocol (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

17

18

Simple Network ManagementProtocol (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