Chu-Sing Yang
Department of Electrical Engineering National Cheng Kung University
Introduction to
Outline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network management
Outline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network management
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
WWW Servers
Remote User
Corp Network Regional Offices WWW Servers WWW Servers Remote User 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
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
Response Times High AvailabilityHigh Availability
Predictability
Predictability
Security
Security
Introduction
Network Management System (NMS)
Automatic versus human effort
Increased network size
Increased complexity
Heterogeneous equipment
Outline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network management
Network Management
Requirements
Ease of use Security features Restoral capability Ability to delete/addAbility to monitor network availability
Traffic rerouting
Improved automation
User registration
Improved reporting
Network Management
Requirements
Control corporate strategic assets
Control complexity
Improve service
Balance various needs
Reduce downtime
Outline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network management
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
Simple Network Management
Protocol
A set of standards for network management
a protocol
a data base structure specification
SNMP Family
SNMPv1
Proposed in 1989SNMPv2
Proposed in 1993 Revised in 1995 An upgrade to SNMPv1Add functional enhancements to SNMP and codify
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
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
Outline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network 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
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
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
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
Requirements for
Configuration Management
The network manager needs the capability toIdentify 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
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
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
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’
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
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?
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
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
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
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
Outline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network management
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
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)
NMA = network management application NME = network management entity Appl = application
Comm = communications software OS = Operating system NMA NME Appi Comm OS Network control Host (manager) NME Comm OS Appi Server (agent) Workstation (agent) NME Comm OS Appi NME Comm OS Router (agent)
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
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
Outline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network management
Network Management
Software Architecture
Three categories
User presentation software
Network management software
Unified user Interface
Presentation of network management Information to users MIB access module Communications protocol stack Network Management application Network Management application Application element Application element Application element
Network management data transport service . . . . . . Network Management application Network Management application Application element Application element Application element
Network management data transport service . . .
. . . Unified
user Interface
Presentation of network management Information to users MIB access module Communications protocol stack Network Management application Network Management application Application element Application element Application element
Network management data transport service . . . . . . Network Management application Network Management application Application element Application element Application element
Network management data transport service . . . . . . Management information base Managed networks Unified user Interface
Presentation of network management Information to users MIB access module Communications protocol stack Network Management application Network Management application Application element Application element Application element
Network management data transport service . . . . . . Network Management application Network Management application Application element Application element Application element
Network management data transport service . . .
. . . Unified
user Interface
Presentation of network management Information to users MIB access module Communications protocol stack Network Management application Network Management application Application element Application element Application element
Network management data transport service . . . . . . Network Management application Network Management application Application element Application element Application element
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
Network Management
Software
Three-layer architecture
Network management application layer
Application element 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
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
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
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
Outline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network management
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
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)
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
Typical distributed management
system architecture
Network Management server Management application MIB Management server Management application MIB Network Element manager Element managerOutline
Introduction
Network Management Requirement
SNMP family
OSI management function areas
Network management system
Network management software architecture
Distributed network management
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
Server stub Client proxy stub Protocol stack Protocol stack Proxy manager Management application Client stub Protocol stack Management application Client stub Protocol stack Standard operations and event reports
Proprietary operations and event reports
