Introduction to Network Management
description
Transcript of Introduction to Network Management
Chu-Sing Yang
Department of Electrical EngineeringNational Cheng Kung University
Introduction to Network Management
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 Typical problem
Remote user arrives at regional office and experiences slow or no response from corporate web server
Where do you begin?Where is the problem?What is the problem?What is the solution?
Without proper network management, these questions are difficult to answer
Corp Network
Regional Offices
WWW Servers
Remote User
Corp Network
Regional Offices
WWW Servers
Remote User
The Case for Management
With proper management tools and procedures in place, you may already have the answer
Consider some possibilities 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?
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
Predictability
Security
Solving Problem Procedure
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 managementa protocola data base structure specificationa set of data objects
SNMP Family SNMPv1
Proposed in 1989 SNMPv2
Proposed in 1993Revised in 1995An upgrade to SNMPv1Add functional enhancements to SNMP and codify
the use of SNMP on OSI-based networks
SNMP Family (cont.)
SNMPv3 Issued in 1998Define a security capability for SNMP and an
architecture for future enhancementsUsed 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 failureReconfigure or modify the network to minimize the
impact of operationRepair 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
Redundant components and alternate communication routes Fault management capability itself should be redundant
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
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 networkGracefully shutting down part or all of the networkMaintaining, 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 End users want to inquire about the upcoming status of resources and their
attributes before reconfiguration Generate configuration reports
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 classAn 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 managementMonitoring
Tracks activities on the networkControlling
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 managersPlan, manage and maintain large networksRecognize 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
NMA = network management application
NME = network management entity
Appl = application
Comm = communications software
OS = Operating system
NMA
NME Appi
CommOS
Network control
Host (manager)
NME
Comm
OS
Appi
Server
(agent)
Workstation
(agent)
NME
Comm
OS
AppiNME
Comm
OS
Router
(agent)
Network Management System
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 networkRespond 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 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 categoriesUser presentation softwareNetwork management softwareCommunications and database support software
Unifieduser
Interface
Presentation of network managementInformation to users
MIBaccessmodule
Communicationsprotocol
stack
NetworkManagementapplication
NetworkManagementapplication
Applicationelement
Applicationelement
Applicationelement
Network management data transport service
. . .
. . .
NetworkManagementapplication
NetworkManagementapplication
Applicationelement
Applicationelement
Applicationelement
Network management data transport service
. . .
. . .
Unifieduser
Interface
Presentation of network managementInformation to users
MIBaccessmodule
Communicationsprotocol
stack
NetworkManagementapplication
NetworkManagementapplication
Applicationelement
Applicationelement
Applicationelement
Network management data transport service
. . .
. . .
NetworkManagementapplication
NetworkManagementapplication
Applicationelement
Applicationelement
Applicationelement
Network management data transport service
. . .
. . .
Managementinformation
base
Managed networks
Unifieduser
Interface
Presentation of network managementInformation to users
MIBaccessmodule
Communicationsprotocol
stack
NetworkManagementapplication
NetworkManagementapplication
Applicationelement
Applicationelement
Applicationelement
Network management data transport service
. . .
. . .
NetworkManagementapplication
NetworkManagementapplication
Applicationelement
Applicationelement
Applicationelement
Network management data transport service
. . .
. . .
Unifieduser
Interface
Presentation of network managementInformation to users
MIBaccessmodule
Communicationsprotocol
stack
NetworkManagementapplication
NetworkManagementapplication
Applicationelement
Applicationelement
Applicationelement
Network management data transport service
. . .
. . .
NetworkManagementapplication
NetworkManagementapplication
Applicationelement
Applicationelement
Applicationelement
Network management data transport service
. . .
. . .
Managementinformation
base
Managed networksManaged networks
Architectural Model of NMS
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 architectureNetwork management application layerApplication element layerNetwork 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 ofa NM protocol used to exchange management
information among managers and agentsa 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 management workstations
be given limited access for monitoring and control manage the departmental resources
one 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 clients
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 network devices Are managed directly by one or more management servers through a vendor-specific element manager or proxy
Typical Distributed Management System Architecture
Network
Management serverManagement
applicationMIB
Management serverManagement
applicationMIB
Network
Elementmanager
Elementmanager
Network resources ( servers, routers, hosts ) with management agents
Management clients ( PCs, workstations )
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 full-blown 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
Server
stub
Client proxy
stub
Protocol
stack
Protocol
stack
Proxy managerManagement
application
Client
stub
Protocol
stack
Management
application
Client
stub
Protocol
stack
Standard operations and event reports
Proprietary operations and event reports
Proxy manager architecture