1. 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

2. Network Management Requirements
Example of approach
Controlling strategic assets
Controlling complexity
Improving service
Balancing various needs: performance, availability, security, cost
Reducing downtime
Controlling costs

3. 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, ….

4. Network Management OSI functional areas
Fault management
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).
Self-identification of system components.
Separate testability of components.

5. Network Management OSI functional areas
Fault management
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 endto-
end 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.

6. Network Management OSI functional areas
Fault management
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

7. Network Management OSI functional classification
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?
Indicators: availability, response time, accuracy service throughput, utilization efficiency

8. Network Management OSI functional classification
Performance management:
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.

9. Network Management OSI functional classification
Configuration and Name Management:
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

10. Network Management OSI functional classification
Configuration and Name Management:
Revert/undo changes
Change management
Configuration audit
Does it do what was intended
Tools for Configuration Management

11. 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

12. 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.

13. 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

14. 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.

15. Organizational Aspects of Management
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).

16. Network Management Scenario

17. Management Information
Manager
Agent
Management Agent
Establishing a Common Terminology Between Manager and Agent
Same meaning of objects and term

18. Management Information
Management information base
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

19. Management Information

20. 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

21. 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

22. Management Information
Categories of Management Information
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

23. Management Information
Categories of Management Information
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

24. Management Information

25. Management Information
MIB Definitions
data processing
data is based on underlying data definitions
Data type (integer, character etc)
MIB definition are also referred to as a model
MIB definition, and model definition are used synonymously
Equipment vendors publish the definitions of the MIBs that their devices implement
MIB definitions that vendors publish must be stable and should not be subjected to change lightly.
Example :TCP connections

26. Management Information
Of Schema and Metaschema
The underlying “real world” that is being abstracted by the model is often called the domain
The schema that underlies the MIB remains constant over time.
The term metaschema means “a schema of a schema,”

27. SNMP Management Information Base (MIB)
Virtual Information Store of MOs
Information are stored at MOs using different approaches
MIB II added a number of useful variables
Structure of Management Information (SMI)
Framework fot the Definition of SNMP MIBs
Object Information Model for Network Management
Formal Description of the Structure are Given Using a Subset of ASN.1
Abstract Syntax Notation 1 (ASN.1)
A Standard Object Definition Language
A Standard Way to Encode Objects for Transfer Over a Network
It’s Large,Complex,and not Especially Efficient

28. Components of SNMP

29. Versions Three major versions SNMPv1, SNMPv2,SNMPv3
SNMPv1 is the recommended standard
SNMPv2 has become split into:
SNMPv2u - SNMPv2 with user-based security
SNMPv2* - SNMPv2 with user-based security and additional features
SNMPv2c - SNMPv2 without security
SNMPv3 – Security and other enhancements

30. The Internet- Standard Management Framework
SNMP is a tool (protocol) that allows for remote and local management of items on the network including servers, workstations, routers, switches and other managed devices.
Comprised of agents and managers
Agent - process running on each managed node collecting information about the device it is running on.
Manager - process running on a management workstation that requests information about devices on the network.

31. The Internet- Standard Management Framework (contd.)
SNMP network management consists of four parts:
Management Information Base (MIB)
A map of the hierarchical order of all managed objects and how they are accessed
Structure of Management Information (SMI)
Rules specifying the format used to define objects managed on the network that the SNMP protocol accesses
SNMP Protocol
Defines format of messages exchanged by management systems and agents.
Specifies the Get, GetNext, Set, and Trap operations
Security and administration capabilities
The addition of these capabilities represents the major enhancement in SNMPv3 over SNMPv2

32. Ports & UDP
SNMP uses User Datagram Protocol (UDP) as the transport mechanism for SNMP messages
Ethernet Frame
IP Packet
UDP Datagram
SNMP Message
CRC
Like FTP, SNMP uses two well-known ports to operate:
UDP Port SNMP Messages
UDP Port SNMP Trap Messages

33. Four Basic Operations Get GetNext Set Trap
Retrieves the value of a MIB variable stored on the agent machine
(integer, string, or address of another MIB variable)
GetNext
Retrieves the next value of the next lexical MIB variable
Set
Changes the value of a MIB variable
Trap
An unsolicited notification sent by an agent to a management application (typically a notification of something unexpected, like an error)

34. Basic operations contd..
get_request
get_response
port 161
get_next_request
get_response
port 161
Manager
Agent
set_request
get_response
port 161
trap
port 162
port 161

35. Traps
Traps are unrequested event reports that are sent to a management system by an SNMP agent process
When a trappable event occurs, a trap message is generated by the agent and is sent to a trap destination (a specific, configured network address)
Many events can be configured to signal a trap, like a network cable fault, failing NIC or Hard Drive, a “General Protection Fault”, or a power supply failure
Traps can also be throttled -- You can limit the number of traps sent per second from the agent
Traps have a priority associated with them -- Critical, Major, Minor, Warning, Marginal, Informational, Normal, Unknown

36. Trap Receivers Traps are received by a management application.
Management applications can handle the trap in a few ways:
Poll the agent that sent the trap for more information about the event, and the status of the rest of the machine.
Log the reception of the trap.
Completely ignore the trap.

37. Languages of SNMP Structure of Management Information (SMI)
specifies the format used for defining managed objects that are accessed via the SNMP protocol
Abstract Syntax Notation One (ASN.1)
used to define the format of SNMP messages and managed objects (MIB modules) using an unambiguous data description format
Basic Encoding Rules (BER)
used to encode the SNMP messages into a format suitable for transmission across a network

38. SNMP MESSAGE ENCODING
THE DESCRIPTION OF MIBS AND MESSAGE FORMATS IS BASED ON THE ASN.1 SYNTAX
THE MAPPING FROM AN ABSTRACT SYNTAX UPON A TRANSFER SYNTAX IS DEFINED BY THE BASIC ENCODING RULES (BER)

39. Basic Message Format Message Length Message Version Community String
Message Preamble
Community String
PDU Header
SNMP Protocol Data Unit
PDU Body

41. 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

42. 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

43. 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