Business data communications 4e chapter 19

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 f

Chapter 19:

Network Management

Business Data Communications, 4e

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

Accounting Management

 Reasons for accounting management:

 Internal chargebacks on network use

 User(s) may be abusing access privileges and burdening the network at the expense of other users

 Users may be making inefficient use of the network, and the network

 The network manager is in a better position to plan for

network growth if user activity is known in sufficient detail.

Configuration Management

 Concerned with:

 initializing a network and grace-fully 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

Performance Management

 Issues of concern to the network manager include:

 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

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

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

Network Management System Architecture

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 NCC when local conditions undergo a significant change

IBM Network Management Architecture and NetView

 Associated with IBM’s Systems Network

Architecture (SNA)

 IBM wants to provide the single, unifying

framework into which all other network

management products feed and from which all the equipment in a user’s network can be controlled

Network Management Categories

 SNA network management is composed of:

Change Management

 Software change control

 Microcode change control

 Hardware change control

Configuration Management

 Physical/logical resource identification

 Resource relationship identification

Performance & Accounting

 Collects session-related information

on logical components of the

network; includes measurements of

data on response time, session

 Status monitor

 Displays status information; reactivates network resources following failures

 Help facilities

 Descriptions of fields on displays, and a systematic problem-solving facility

 Customization facilities:

 Permits a user to tailor NetView

Technical Control

 Automatic and remote testing and monitoring of the

system, to reduce downtime due to the need to locate service personnel

 Restoring and/or reconfiguring the system upon failure

in real time

 Providing network performance and functioning

Component-Level Technical

Control

 Line Monitors

 Captures the signal between a host system and the network

 Generally employed only on the network end

 Protocol Analyzers

 Can also simulate various network components

 Can test communication protocols and codes

 Typically handles up to layer 3 of the OSI architecture

Network Technical Control Systems

 Integrate control devices and centralize the control of the network

Performance Monitoring

 After availability, the second most important

characteristic of a network is performance

 Performance data must be available in sufficient detail to be able to assess the bottleneck that is causing the problem and to plan appropriate

remedial action

 Events: Number of occurrences of specific events

 Timing: Timing the duration of a specific signal

 Software monitors

 Gathers and reports statistics on hardware and systems and

Network Monitoring Systems

Simple Network Management

Protocol (SNMP)

 Network Management Model

 Management station

 Management agent

 Management information base

 Network management protocol

Role of SNMP

Protocol Specification

 Transmission of a message

 Receipt of a message

 Variable bindings

 Released in 1992, revised in 1996

 Addressed functional deficiencies in SNMP

 Accommodates decentralized network management

 Improves efficiency of data transfer

 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

 Provides three important services: authentication, privacy, and access control