Transcript Network Management Basics

Network Management
Basics
• Network management requirements
• OSI Management Functional Areas
– Network monitoring: performance, fault, accounting
– Network control: configuration, security
• Standardization in network management
• Practical issue: introduction to SNMP
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Network Management
Requirements
Example of approach
• Controlling strategic assets
• Controlling complexity
• Improving service
• Balancing various needs: performance, availability,
security, cost
• Reducing downtime
• Controlling costs
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Network Management
OSI functional areas
• Fault management
– Detect the fault
– Determine exactly where the fault is
– Isolate the rest of the network from the failure so that it can continue to
function
– Reconfigure or modify the network in such a way as to minimize the
impact
– Repair or replace the failed components
– Tests: connectivity, data integrity, response-time, ….
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Network Management
OSI functional areas
• Fault management
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Monitoring network and system state.
Responding and reacting to alarms.
Diagnosing fault causes (i.e., fault isolation and root-cause analysis).
Establishing error propagation.
Introducing and checking error recovery measures (i.e., testing and
verification).
Operating trouble ticket systems.
Providing assistance to users (user help desk).
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Network Management
OSI functional areas
• Fault management
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The following technical capabilities and important aids for fault management
can assist in fault analysis:
Self-identification of system components.
Separate testability of components.
Trace facility (i.e., keeping records of switched message traffic or labeling
messages
for the purpose of traceability or special compatibility reports).
Error logs.
Message echoes at all protocol layers (i.e., at transmission links and on an endtoend basis), such as “heartbeat” or “keep alive” messages that detect failure.
Retrieval possibilities for memory dumps.
Start possibilities (which can also be initiated and monitored centrally) for selftest.
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Network Management
OSI functional areas
• Fault management
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ping and trace route analysis of network reachability.
Triggering of planned resets and restarts (directed to specific ports, port
groups,and components).
Availability of special test systems (e.g. interface checkers, protocol
analyzers, hardware monitors for line supervision).
Support of filter mechanisms for fault messages or alarms and event
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Network Management
OSI functional classification
• Performance management:
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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?
– Indicators: availability, response time, accuracy
throughput, utilization
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service
efficiency
Network Management
OSI functional classification
• Performance management:
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Vertical QOS mapping (e.g. speech quality)
Horizontal QOS mapping (e.g. protocols)
Establishing QoS parameters and metrics.
Monitoring all resources for performance bottlenecks and threshold crossings.
Carrying out measurements and trend analysis to predict failure before it occurs.
Evaluating history logs (i.e., records on system activity, error files).
Processing measurement data and compiling performance reports.
Carrying out performance and capacity planning.
Description of reactions to changes of the QoS parameters mentioned earlier.
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Network Management
OSI functional classification
• Configuration and Name Management:
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A description of a distributed system
The process of configuration
Installation of new hardware/software
Tracking changes in control configuration
Who, what and why? - network topology
User interface of the configurator
Location of configuration
Storage of configuration
Validity of configuration
The result of a configuration process
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Network Management
OSI functional classification
• Configuration and Name Management:
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Revert/undo changes
Change management
Configuration audit
Does it do what was intended
Tools for Configuration Management
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Network Management
OSI functional classification
• Security management
• Passive attacks: theft of information (passwords, etc.).
• Active attacks: masquerades (i.e., users pretending to be someone
else, or
• repeating, giving priority to or delaying message; (unauthorized
access, viruses, Trojan horses, denial-of-service attacks).
• Malfunctioning of resources.
• Faulty or inappropriate behavior and incorrect response operation.
• Security services: generating, distributing, storing of encryption keys
for services
• Exception alarm generation, detection of problems
• Backups, data security
• Security logging
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Network Management
OSI functional classification
• Break down of security management tasks
• Conducting threat analyses.
• Defining and enforcing security policies.
• Checking identity (authentication based on signatures, certificates).
• Carrying out and enforcing access controls.
• Guaranteeing confidentiality (encryption).
• Ensuring data integrity (message authentication).
• Monitoring systems to prevent threats to security.
• Reporting on security status and violations or attempted violations.
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Network Management
OSI functional classification
• Accounting management
– Identifying consumers and suppliers of network resources - users
and groups
– Mapping network resources consumption to customer identity
– Billing
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Organizational Aspects of
Management
• Specifying interfaces between domains to enable the
exchange of management
• information and the invocation of management actions.
• Planning and establishing a management infrastructure.
• defining procedures for implementing the management
processes
• the tool functionality required.
• Establishing an operational and organizational structure for
carrying out management.
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Organizational Aspects of
Management
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Organizational structure of a particular company (teams, groups,
departments, operating areas).
Geographical conditions (country, location, campus, building).
Business areas.
Data processing–related aspects (e.g., LAN/WAN, central/distributed DP)
Types of resources (hardware, system software, applications software,
data, operating materials, premises, technical infrastructure).
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Network Management Scenario
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Management Information
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Manager
Agent
Management Agent
Establishing a Common Terminology
Between Manager and Agent
– Same meaning of objects and term
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Management Information
• Management information base
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The Managed Device as a Conceptual Data Store
The MIB is not the same as a database
One kind of information
One aspect
Physical aspect
Logical aspect
Manager can manipulate the information in MIB
Managed object (MO)
Real resource
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Management Information
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Management Information
• Categories of Management Information
• State information
– current state of physical and logical resources
– current alarm conditions
– Current CPU load, and utilization of bandwidth and memory.
• Physical configuration information
– device type
– physical configuration in terms of cards and available ports
– MAC addresses
– configuration information changes only rarely
– Stored
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Management Information
• Categories of Management Information
• Logical configuration information
– IP addresses
– telephone numbers
– logical interfaces
– can be changed by management applications and administrators
– startup configuration information
– transient configuration information
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Management Information
• Categories of Management Information
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Historical information
– This includes historical snapshots of performance-related state
– It is not the part of MIB
– It is simply “data” that is stored at the device
The Difference Between a MIB and a Database
• Footprint
• general-purpose processing capabilities.
• Specific management requirements
• Real effects
• Real world resource
• Characteristics of the contained data
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Management Information
• Categories of Management Information
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The Relationship Between MIBs and Management Protocols
– SNMP
– Structure of Management Information (SMI)
– MIB does not depend on any particular management protocol
– HTML
– Protocol is depended on MIB
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Management Information
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Network Management
Some ideas
• Managed objects: functions provided by the network
• Element Management Systems (EMS): managing a
specific portion of the network (may manage async lines,
multiplexers, routers)
• Managers of Manager Systems (MoM): integrate together
information from several EMS
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Network Management
Standards
• Internet approach: Simple Network Management Protocol
(SNMP, secure SNMP, SNMP v2)
• OSI approach: CMIP - common management information
protocol, CMIS - common management information
service (user interface)
We concentrate on SNMP
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Network Management
Proprietary solutions
• The world of Microsoft PC software:
Windows NT + several (or hundreds) of PCs with
Windows 95 (98??)
• Solution: Microsoft SMS software:
full control over workstations (Windows95) from central NT server
software configuration, updates, full inventory
• NT world - incorporates SNMP mechanisms
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