Guide to TCP/IP, Third Edition : Guide to TCP/IP, Third Edition Chapter 11:
Monitoring and Managing IP Networks
Objectives : Monitoring and Managing IP Networks 2 Objectives Understand the basic principles and practices involved in managing modern networks
Explain the role that the SNMP can play on an IP-based network, and understand its basic structure and function
Understand how to install, configure, and use SNMP consoles, tools, and utilities
Objectives (continued) : Monitoring and Managing IP Networks 3 Objectives (continued) Deploy tools and utilities to maintain an SNMP network management system
Explain the issues involved in integrating SNMP-based network management tools with other network management environments
Understand common SNMP errors and how to troubleshoot them
Understanding Network Management Practices and Principles : Monitoring and Managing IP Networks 4 Understanding Network Management Practices and Principles Tasks involved in managing a network
Depend on the ability to collect data about a network and detect network-related occurrences
End stations
Usually known as managed devices
Any kind of system where management-related software is installed and running
Management entities
Usually function within the context of a network management system (NMS)
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The OSI Network Management Model : Monitoring and Managing IP Networks 6 The OSI Network Management Model OSI network management model incorporates the following five layers
Accounting management
Configuration management
Fault management
Performance management
Security management
Practical Network Management : Monitoring and Managing IP Networks 7 Practical Network Management OSI network management model
Does an excellent job of categorizing and cataloging tasks and activities
Make systematic network management a priority
Obtain right mix of software components and tools that can be used as part of a program of
Regular, scheduled network maintenance and care
In-band Versus Out-of-band Management : Monitoring and Managing IP Networks 8 In-band Versus Out-of-band Management In-band management
Traffic travels along the regular network data path.
Out-of-band management
Traffic alerts travel on a separate non-data path
Solution supports communications between management agents and the manager device
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Understanding SNMP : Monitoring and Managing IP Networks 11 Understanding SNMP Request/response-based protocol used to
Transport management messages between an SNMP agent and an SNMP manager
SNMP version 1 (SNMPv1)
Uses plain text passwords
SNMP version 2 (SNMPv2)
Includes two improvements: protocol enhancements and security enhancements
SNMP version 3 (SNMPv3)
Addresses shortcomings of previous versions
Understanding SNMP (continued) : Monitoring and Managing IP Networks 12 Understanding SNMP (continued) SNMPv1 consists of the following basic elements:
Management Information Base objects
SNMP agents
SNMP managers
SNMP messages
Management Information Base Objects : Monitoring and Managing IP Networks 13 Management Information Base Objects Management Information Base (MIB)
Database of manageable objects for a device
Structure of Management Information (SMI)
Defines object formats in any MIB using a particular form of notation called Abstract Syntax Notation One (ASN.1)
ASN.1
Language used to describe a type of object and the object identifier (OID)
Management Information Base Objects (continued) : Monitoring and Managing IP Networks 14 Management Information Base Objects (continued) OID
Sequence of non-negative integers that traverses an object tree
Subordinates
Branches of the object tree
In SNMP
Object is identified by the path used to get to a specific device identifier on an object tree
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Remote Monitoring : Monitoring and Managing IP Networks 19 Remote Monitoring Used to monitor and administer remote segments of a distributed network
Places agents, called network probes, at various locations on the distributed network
Probes
Standalone devices that contain a NIC, a processor, memory, and software
ROM Ethernet : Monitoring and Managing IP Networks 20 ROM Ethernet First version of RMON
Ethernet based
Has nine distinct groups of objects
Ethernet statistics, History control
Alarm, Host
HostTopN, Matrix
Filter, Packet capture
Event
SNMP Agents : Monitoring and Managing IP Networks 21 SNMP Agents SNMP agent software
Placed on devices that can be managed by SNMP managers
SNMP agents
Answer to SNMP manager’s queries for information about the objects in agent’s MIB
SNMP managers
Query SNMP agents for the information maintained about MIB objects
SNMP Messages : Monitoring and Managing IP Networks 22 SNMP Messages SNMP managers and agents communicate over UDP with a specific set of commands
GET-REQUEST
GET-RESPONSE
GET-NEXT
SET
TRAP
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SNMP Security : Monitoring and Managing IP Networks 24 SNMP Security SNMPv1
Offers only a simple password system, and cannot be considered truly secure
Basic community names
Read-Only (or Monitor) community name
Read/Write (or Control) community name
Alert (or Trap) community name
Installing and Configuring SNMP Agents and Consoles : Monitoring and Managing IP Networks 25 Installing and Configuring SNMP Agents and Consoles Installing a network management console is more complex than installing agent software
Many proprietary consoles that differ greatly from one another
Console configuration also is fairly complex
For many packages, completing an initial configuration may take six months or longer
Configuration is never truly finished
Typically require dedicated resources and constant maintenance
SNMP Consoles, Tools, Utilities, and Key Files : Monitoring and Managing IP Networks 26 SNMP Consoles, Tools, Utilities, and Key Files Lion’s share of market belongs to three products
HP OpenView’s Network Node Manager (NNM) Advanced Edition
IBM’s Tivoli NetView
Computer Associates’ Unicenter
Integrating SNMP with Other Management Environments : Monitoring and Managing IP Networks 27 Integrating SNMP with Other Management Environments Common modules
PING
Database change control modules
Dynamic topological maps
Inventory modules
Service-level tracking
To effectively use data gathered via SNMP
Other managed environments usually have reporting capabilities
Troubleshooting SNMP : Monitoring and Managing IP Networks 28 Troubleshooting SNMP Community names
Must match on both the SNMP agent and the network management station
Case sensitive
Three levels of community strings
Read-Only (Monitor)
Read/Write (Control)
Alert (Trap)
Summary : Monitoring and Managing IP Networks 29 Summary Network management
Involves placing specific software components, called management agents, into managed devices
Network management systems rely on two kinds of activities to perform management tasks
The ability of managed devices to issue alerts when specific events occur
The ability of management entities to poll managed devices regularly
Summary (continued) : Monitoring and Managing IP Networks 30 Summary (continued) Most NMSs
Provide various methods for out-of-band management
Discipline of network management
Described in the OSI network management model
For IP-based networks
SNMP carries management-related messages and data among network management agents and entities
Summary (continued) : Monitoring and Managing IP Networks 31 Summary (continued) SNMP’s management data
Resides in a database of manageable objects called a Management Information Base
Order is important
When loading MIBs into a management station
Remote Monitoring MIB
Used to monitor and manage remote segments on a distributed network
Summary (continued) : Monitoring and Managing IP Networks 32 Summary (continued) SNMP messages
Use UDP for transport and IP for network access
Ensuring SNMP security requires
Changing default community names
Managing the transit of SNMP messages across organizational network Boundaries
Troubleshooting SNMP requires
Good working knowledge of local network conditions