Transcript Introduction to Network Management

Introduction to
Network Management
Chu-Sing Yang
Department of Electrical Engineering
National Cheng Kung University
Outline
Introduction
 Network Management Requirement
 SNMP Family
 OSI Management Function Areas
 Network Management System
 Network Management Software Architecture
 Distributed Network Management
 Proxies

Outline
Introduction
 Network Management Requirement
 SNMP Family
 OSI Management Function Areas
 Network Management System
 Network Management Software Architecture
 Distributed Network Management
 Proxies

The Case for Management
Remote User

Typical problem
Remote
user arrives at regional
office and experiences slow or no
response from corporate web
server

Where do you begin?
Where

Regional Offices
is the problem?
What
is the problem?
What
is the solution?
Without proper network
management, these questions
are difficult to answer
WWW Servers
Corp Network
The Case for Management
Remote User
 With proper management tools and
procedures in place, you may
already have the answer
 Consider some possibilities
Regional Offices
 1. What configuration changes were
made overnight?
 2. Have you received a device fault
notification indicating the issue?
 3. Have you detected a security
breach?
 4. Has your performance baseline
predicted this behavior on an
increasingly congested network link?
WWW Servers
Corp Network
Solving Problem Procedure



An accurate database of
your network’s topology,
configuration, and
performance
A solid understanding of the
protocols and models used
in communication between
your management server and
the managed devices
Methods and tools that allow
you to interpret and act upon
gathered information
Response Times
High Availability
Security
Predictability
Introduction

Network Management System (NMS)
 Automatic
versus human effort
 Increased network size
 Increased complexity
Heterogeneous equipment
 Equipment from multiple vendors

Outline
Introduction
 Network Management Requirement
 SNMP Family
 OSI Management Function Areas
 Network Management System
 Network Management Software Architecture
 Distributed Network Management
 Proxies

Network Management
Requirements










Ease of use
Security features
Restoral capability
Ability to delete/add
Ability to monitor network availability
Traffic rerouting
Improved automation
User registration
Improved reporting
Ability to monitor response time
Network Management
Requirements
Control corporate strategic assets
 Control complexity
 Improve service
 Balance various needs
 Reduce downtime
 Control cost

Outline
Introduction
 Network Management Requirement
 SNMP Family
 OSI Management Function Areas
 Network Management System
 Network Management Software Architecture
 Distributed Network Management
 Proxies

Introduction to SNMP

Simple Network Management Protocol
 Provides
a tool
for multi-vender, interoperable network management
 used across a broad spectrum of product types


include end systems, bridges, switches, routers and
telecommunications equipment
 TCP/IP
based
Simple Network Management
Protocol

A set of standards for network management
a
protocol
 a data base structure specification
 a set of data objects
SNMP Family

SNMPv1
 Proposed

in 1989
SNMPv2
 Proposed
in 1993
 Revised in 1995
 An upgrade to SNMPv1
 Add functional enhancements to SNMP and codify
the use of SNMP on OSI-based networks
SNMP Family (cont.)

SNMPv3
 Issued
in 1998
 Define a security capability for SNMP and an
architecture for future enhancements
 Used with the functionality provided by SNMPv2
or SNMPv1
RMON
Remote network MONitoring
 a supplement to SNMP
 extend the capabilities of SNMP to include
management of LANs as well as the devices
attached to those networks
 RMON 1 issued in 1991
 RMON 2 issued in 1995

Outline
Introduction
 Network Management Requirement
 SNMP Family
 OSI Management Function Areas
 Network Management System
 Network Management Software Architecture
 Distributed Network Management
 Proxies

OSI Management Functional
Areas
Fault management
 Configuration management
 Accounting management
 Performance management
 Security management

Fault Management


The facilities that enable the detection, isolation, and
correction of abnormal operation of the OSI environment
What is “a fault”?
 an
abnormal condition that requires management attention (or
action) to repair
 indicated by failure to operate correctly or by excessive
errors



Communication line is cut
A crimp in the cable
Certain errors may occur occasionally and are not normally considered
to be faults
Fault Management

When a fault occurs
 Determine
“exactly” where the fault is
 Isolate the rest of the network from the failure
 Reconfigure or modify the network to minimize the
impact of operation
 Repair or replace the failed components
User requirements for
Fault Management

Fast and reliable problem resolution



Receive notification and correct the problem immediately
Requires rapid and reliable fault detection and diagnostic management
Provides fault tolerance



Keep informed of the network status


Reassurance of correct network operation through mechanisms that use tests
or analyze dumps, logs, alerts, or statistics
Problem tracking and control


Redundant components and alternate communication routes
Fault management capability itself should be redundant
Ensure the problem is truly resolved and no new problems are introduced
Fault management should have minimal effect on network
performance
Configuration Management

Configuration management is concerned with
 Initializing
a network
 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
Requirements for
Configuration Management

The network manager needs the capability to

Identify initially the components that comprise the network
 Define and change the connectivity of components
 Define and modify default attributes, and load the predefined sets of
attributes into the specified network components
 Reconfigure a network for performance evaluation, network upgrade, fault
recovery or security checks


Generate configuration reports



End users want to inquire about the upcoming status of resources and their
attributes before reconfiguration
Periodic basis
Response for a request
Only authorized end users can manage and control network operation
(software distribution and updating)
Accounting Management

The facilities that enable
 charges
to be established for the use of managed
objects
 costs to be identified for the use of those managed
objects
Accounting Management

Network managers track the use of network
resources by end user or end-user class
 An
end user or group of end users may be abusing its
access privileges and burdening the network at the
expense of other users
 End users may be making inefficient use of the
network, and network manager can assist in changing
procedures to improve performance
 The network manager is easier to plan for network
growth if end user activity is known in sufficient detail
Requirements for
Accounting Management

The network manager can specify
 the
kinds of accounting information to be recorded at
various nodes
 the desired interval between sending the recorded
information to higher-level management nodes
 the algorithms to be used in calculating the charging
Generate accounting reports
 Provide the capability to verify end users’
authorization to access and manipulate the
information

Performance Management

The facilities needed to evaluate
 the
behavior of managed objects
 the effectiveness of communication activities

Functions of performance management
 Monitoring

Tracks activities on the network
 Controlling

Enables performance management to make
adjustments to improve network performance
Issues of 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?

To Deal the Issues of PM

The network manager focus on some initial set of
resources to be monitored in order to assess
performance levels
 Appropriate
metrics and values with relevant network
resources as indicators of different levels of performance

The count of retransmission on a transport connection
 Monitor
many resources to provide information in determining
network operating level
 Collect and analyze information, and then using the resultant
analysis as feedback to the prescribed set of values
User Requirements for
Performance Management

End users want to know
 the
average and worst case response times
 the reliability of network services

Performance statistics can help managers
 Plan,
manage and maintain large networks
 Recognize potential bottlenecks in advance

balance or redistribute traffic load by changing routing
tables
Security Management

The facilities that address those aspects of OSI
security essential to
 Operate
OSI network management correctly
 Protect managed objects



network resources
end user information
End users want to know
 the
proper security policies are in force and effective
 the management of security facilities is itself secure
Issues of Security
Management

Managing information protection, and access control
facilities
 Generating,
distributing and storing encryption keys
 Passwords, authorization or access control information must be
maintained and distributed

Monitoring and controlling access to computer networks
and to all or part of the network management information
 SM
involves with the collection, storage, and examination of
audit records and security logs
 the enabling and disabling of these logging facilities
Outline
Introduction
 Network Management Requirement
 SNMP Family
 OSI Management Function Areas
 Network Management System
 Network Management Software Architecture
 Distributed Network Management
 Proxies

Network Management
Systems (NMS)

NMS is a collection of tools for network monitoring and
control
 Designed


to view the entire network as a unified architecture
addresses and labels assigned to each point
specific attributes of each element and link known to the system
 Single
operator interface with a powerful but user-friendly set
of commands
 a minimal amount of separate equipment (hardware/software)
is necessary

NMS software resides in the host computers and
communications processors (bridges, routers)
Network Management
Systems



The active elements of the network provide regular
feedback of status information to the network control
center
NMS for single vendor equipment versus for
multiple-vendor network
Two or more network control centers are used
 for
high availability (backup)
 one center is idle or collecting statistics
 the other center is used for control
Network Management System
Network control
Server
Host (manager)
(agent)
NMA
NME
NME
Appi
Comm
Comm
OS
Workstation
(agent)
OS
Router
(agent)
NMA = network management application
NME
NME
Appi
Comm
OS
Appi
NME = network management entity
Appl = application
Comm
Comm = communications software
OS = Operating system
OS
Network Management
Configuration

Network Management Element (NME)







Contains a collection of software devoted to the NM task in each network
node
collects statistics
Stores statistics locally
Responds to commands from network control center (manager)
 Transmit collect statistics to manager
 Change a parameters (a timer in a transport protocol)
 Provide status information
 Generate artificial traffic for testing
Send messages to network control center for significant changes in local
conditions
be referred to as an agent
Agents are implemented in end systems and nodes
Network Management
Configuration

Network Management Application (NMA)
 include
an operator interface to allow an
authorized user to manage the network
 Respond to user commands
display information
 issue commands to NMEs through the network

 Communicate
with and control NME in other
nodes

Application-level network management protocol
Outline

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
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



Introduction
Network Management Requirement
SNMP Family
OSI Management Function Areas
Network Management System
Network Management Software Architecture
Distributed Network Management
Proxies
Network Management
Software Architecture

Three categories
 User
presentation software
 Network management software
 Communications and database support software
Architectural Model of NMS
Unified
user
Interface
Presentation of network management
Information to users
Network
Management
application
Application
element
. . .
Application
element
Network
Management
application
. . .
Application
element
Network management data transport service
MIB
access
module
Management
information
base
Communications
protocol
stack
Managed networks
User Presentation Software

An interface in manager systems
 monitor

and control the network
An interface in agent systems
 network
testing and debugging
 view or set parameters locally

Presentation tools
 to
organize, summarize, and simplify the information as
much as possible to avoid information overload
 graphical presentations
 user interface should be the same at any node, regardless
of vender
Network Management
Software

Three-layer architecture
 Network
management application layer
 Application element layer
 Network management data transport service layer
Network Management
Software (Cont’)

Network management application
 Provides services of interest to users
 FCAPS
 Each application covers a broad area
of network management
and should exhibit consistency over various types of
configurations (LAN, WAN, ..)

Application elements
 Implement
primitive and general-purpose network management
functions

generating alarms or summarizing data
 Implement
basic tools used by one or more network
management applications
 Developed based on software reuse
Network Management Data
Transport Service

The module consists of
a
NM protocol used to exchange management
information among managers and agents
 a service interface to the application elements

Provides very primitive functions (get, set and trap)
Communication & Database
Support Software


Network management software needs access to a
local MIB, and to remote agents and managers
Local MIB at an agent contains
 Information
reflecting the configuration and behavior of this
node
 Parameters used to control the operation of this node

Local MIB at a manager contains
 node-specific
information
 summary information about agents under control
Communication & Database
Support Software

MIB access module
 Include
basic file management software that enables
access to the MIB
 Convert local MIB format to a standardized form across the
NMS

Communications protocol stack
 OSI
or TCP/IP stack
 Support the network management protocol
 Support communications among agents and managers
Outline
Introduction
 Network Management Requirement
 SNMP Family
 OSI Management Function Areas
 Network Management System
 Network Management Software Architecture
 Distributed Network Management
 Proxies

Distributed Network
Management


A centralized NMS enables the manager to maintain control over
the entire configuration, balancing resource against needs and
optimizing the overall utilization of resources
Why distributed network management?





the proliferation of low-cost, high power PCs & workstations
the proliferation of departmental LANs
local control and optimization of distributed applications
distributed computing
Architecture of distributed network management


hierarchical architecture
department-level managers
 manage downsized applications and PC LANs
Distributed Network
Management

Benefits
 network
management traffic overhead is minimized
 Offers greater scalability
 eliminates single-point failure

Elements for hierarchical architecture
 distributed


be given limited access for monitoring and control
manage the departmental resources
 one


management workstations
central workstation (with a backup)
global access rights to manage all network resources
interact with less-enabled management stations
Distributed Network
Management

Distributed management system architecture
 management



Provide the user access to management services and
information
Provide a graphical user interface
may access one or more management servers
 management




servers are the heart of the system
support a set of management applications and a MIB
store common management data models
route management information to applications and clients
 managed

clients
network devices
Are managed directly by one or more management servers
through a vendor-specific element manager or proxy
Typical Distributed Management
System Architecture
Management clients ( PCs, workstations )
Network
Management server
Management server
Management
application
Management
application
MIB
MIB
Network
Element
manager
Element
manager
Network resources ( servers, routers, hosts ) with management agents
Outline
Introduction
 Network Management Requirement
 SNMP Family
 OSI Management Function Areas
 Network Management System
 Network Management Software Architecture
 Distributed Network Management
 Proxies

Proxies

Why proxies?
 older
systems may not support network management
standards
 small systems are not suitable to be implemented fullblown NME
 some components do not support agent software


Modems and multiplexers
Operations of proxies
 translate
requests and responses among managers and
the target system
 act on behalf of one or more other nodes
Proxy manager architecture
Management
Management
Proxy manager
application
application
Client
Server
Client proxy
Client
stub
stub
stub
stub
Protocol
Protocol
Protocol
Protocol
stack
stack
stack
stack
Standard operations
and event reports
Proprietary operations and
event reports