PA160: Net-Centric Computing II. Network Management
Luděk Matýska
Slides by: Tomáš Rebok Faculty of Informatics Masaryk University
Spring 2011
Luděk Matýska  (Fl MU)
2. Network Management
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Lecture overview
Lecture overview
(1) Motivation
(2) Network Management
o Network Management by ISO
(3) Basic Network Management Components o Network Elements
Management Systems Management Network Management Support Organization o Basic Components Refined
,4) Simple Network Management Protocol (SNMP) Structure of Management Information Management Information Base (MIB) Simple Network Management Protocol (SNMP)
(5) Conclusion
2. Network Management
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Motivation
Lecture overview
Motivation
2| Network Management
• Network Management by ISO
3^ Basic Network Management Components
• Network Elements Management Systems Management Network Management Support Organization
• Basic Components Refined
4) Simple Network Management Protocol (SNMP) Structure of Management Information
• Management Information Base (MIB)
• Simple Network Management Protocol (SNMP)
5& Conclusion
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Motivation
The Case for Management I.
o typical problem
o remote user arrives at regional office and experiences slow or no response from corporate web server
o Where should we begin? o Where is the problem? o What is the problem? o What is the solution?
o without proper network management, these questions are difficult to answer
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Motivation
The Case for Management II.
with proper management procedures and tools, one may "easily" get the answer
consider some possibilities:
o What configuration changes were
made overnight? o Have you received a device fault
notification indicating the issue?
Have you detected a security breach? o Has your performance baseline
predicted this behavior on an
increasingly congested network link?
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Motivation
The Case for Management III.
A bit of history
o during the old days, a network could be managed using human efforts only
• in a small system, running few "pings" may help locating the problem
o 27. 10. 1980: first real (ARPANET) network crash o described in RFC 789
o including the steps performed for the recovery o further experiences obtained on similar cases
• e.g., a "worm" in 1988
o as the Internet becomes a large global infrastructure, automated network management and monitoring tools are essential
o standardized tools that can be used across a broad spectrum of product
types are also needed (heterogenous equipment) q == Network Management == Network Management System (NMS)
Ludek Matyska  (FI MU) 2. Network Management Spring 2011 6/64
Motivation
The Case for Management III.
What should be monitored?
What should be monitored?
o basic network elements
o network interfaces - e.g., an increase in checksum errors in frames sent
out by the interface o network components - servers, routers, end-hosts, etc. o physical links
o traffic monitoring - by link utilization monitoring, system bottlenecks
may be determined (and solved) o routing information - e.g., rapid changes in routing tables o a compliance with SLAs (Service Level Agreements)
o suspicious behavior - security attacks, patterns indicating suspicious traffic, etc.
o etc.
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Network Management
Lecture overview
Motivation
2) Network Management
o Network Management by ISO
3^ Basic Network Management Components
• Network Elements Management Systems Management Network Management Support Organization
• Basic Components Refined
4) Simple Network Management Protocol (SNMP) Structure of Management Information
• Management Information Base (MIB)
• Simple Network Management Protocol (SNMP)
5& Conclusion
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Network Management
• the process of controlling a complex data network
• controlling = monitoring, testing, configuring, and troubleshooting
• the overall goal is to help with the complexity of the network and to ensure that data can go across it with maximum efficiency and transparency to the users
Network Management
Network management includes the deployment, integration and coordination of the hardware, software, and human elements to monitor, test, poll, configure, analyze, evaluate, and control the network and element resources to meet the real-time, operational performance, and Quality of Service requirements at a reasonable cost.
Luděk Matýska  (Fl MU)
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Network Management      Network Management by ISO
Network Management by ISO
ISO (International Organization for Standardization) has created a network management model (often referred as FCAPS model):
o Fault management
o Configuration management
o Accounting management
o Performance management
o Security management this classification has gained broad acceptance by vendors of both standardized and proprietary NMSs
o the model does not define the actual implementation of a NMS
Ludek Matyska (FI MU)
— Ca pacity
— Traffic —Throughput
— Response time 2. Network Management
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Network Management      Network Management by ISO
Network Management by ISO
Fault Management
o a fault = an abnormal condition that requires management attention (or action) to repair
Fault management:
o the facilities that enable the detection, isolation, and correction of abnormal operation of the network
o deals with both HW & SW failures
o includes logging the detected information o two variants:
o Reactive Fault Management - reacts to incurred errors; involves the following steps:
a discovering the problem o isolating the problem o fixing the problem (if possible) o and documenting the problem q Proactive Fault Management - tries to prevent faults from occurring o provides alarms - unsolicited messages indicating that some unexpected event has occurred in the network (link down, intrusion detected, etc.)
Ludek Matyska  (FIMU) 2. Network Management Spring 2011 11/64
Network Management      Network Management by ISO
Network Management by ISO
Configuration management
Configuration management:
o includes functionality to perform operations that will deliver and modify configuration settings to equipment in the network
o includes the initial configuration of a device to bring it up as well as ongoing
configuration changes o includes both HW & SW configurations o includes (HW & SW) documentation as well o functions:
o configuring Managed Resources • auditing the network and discovery what's in it o synchronization management information in the network o backing up network configuration and restoring o managing software images running on network equipment steps:
J} gather information about current network, maintain an up-to-date inventory
of all network components [2) (if necessary) use that data to modify the configuration of the network
devices (= reconfiguration)
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Network Management      Network Management by ISO
Network Management by ISO
Accounting Management
Accounting management:
o concerned with tracking network utilization information, such that individual users, departments, or business units can be appropriately billed or charged for accounting purposes
o but does not serve for charging purposes only - tracking network utilization information can be also used for:
o detecting users that are abusing their access privileges and burdening
the network at the expense of other users o detecting users making inefficient use of the network (network
managers can assist in changing procedures to improve performance) network managers to plan the network growth (easier when end user activity is known in sufficient detail)
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Network Management      Network Management by ISO
Network Management by ISO
Performance Management
Performance management:
o involves measuring the performance of the network hardware, software, and media
o e.g., overall throughput, percentage utilization, error rates, response time, etc.
o measures both individual and complex components (e.g., an end-to-end path)
o tries to monitor and control the network to ensure that it is running as efficiently as possible
o closely related to fault management (but considers long-term behavior) functional categories:
o Monitoring - ability to monitor and track activities on the network o Controlling - ability to make adjustments to improve network performance
o performance statistics can help managers to: o plan, manage and maintain large networks o recognize potential bottlenecks in advance
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Network Management      Network Management by ISO
Network Management by ISO
Security Management
Security management:
o responsible for controlling access to the network based on a predefined policy
requires identifying the sensitive information (e.g., network management information), which should be protected
provides audit trails and sounds alarms for security breaches
not only concerned with ensuring that a network environment is secure, but also that gathered security-related information is analyzed regularly
includes network authentication, authorization, and auditing o together with firewalls and IDSs
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Basic Network Management Components
Lecture overview
Motivation
2f Network Management
• Network Management by ISO
3^ Basic Network Management Components
o Network Elements Management Systems Management Network Management Support Organization
o Basic Components Refined
4^ Simple Network Management Protocol (SNMP) Structure of Management Information
• Management Information Base (MIB)
• Simple Network Management Protocol (SNMP)
5& Conclusion
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Basic Network Management Components
Basic Components of Network Management Systems
Management	© t» <? a 19 «?
Support	
Organization	
Management Systems
f
Management Network
T
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Basic Network Management Components     Network Elements
Network Elements (NEs) I.
Network Devices — Network Elements (NEs)
o to be managed, every NE must offer a management interface through which a managing system can communicate with it o receives requests and responses to them
o sends unsolicited information, when an unexpected event has occurred (e.g., failure of a fan or a buffer overflow)
o a managing application = manager, the network element = agent
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Basic Network Management Components      Network Elements
Network Elements (NEs) II.
Management Agents I.
NEs have to provide a piece of software that implements the management interface
o = Management Agent
• "agent" becomes overloaded
o agent = the role that a network element plays in network management o agent = software component that allows the network element to play that role (provides the management interface)
• management agent's functionality:
o collects statistics (stores them locally)
• responds to manager's commands, e.g.:
sends the collected statistics • provides/changes the node's parameters o provides status information
o sends unsolicited messages for significant changes in local conditions etc.
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Basic Network Management Components      Network Elements
Network Elements (NEs) II.
Management Agents II.
o the (Management) Agent consists of three main parts:
o management interface - handles management communication
• supports a management protocol that defines the "rules of conversation"
o Management Information Base (MIB) - a conceptual data store that contains a management view of the device being managed o a way to view the device itself, not a database in which information
about the device is stored o constitutes the management information (provides an abstraction of real-world aspects (= managed objects) for management purposes) core agent logic - translates between the operation of the management interface, the MIB, and the actual device
• e.g., translates the request "retrieve a counter" (referred to in the MIB) into an internal operation that reads out a device hardware register containing the desired information
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Basic Network Management Components     Network Elements
Network Elements (NEs) II.
Management Agents III.
Figure: Anatomy of a Management Agent.
Ludek Matyska  (FI MU)
2. Network Management
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Basic Network Management Components      Network Elements
Network Elements (NEs) II.
Management Agents IV.
Management Agents cont'd. o a single network element can contain several management agents managing the same objects
o each of which with its own management interface
o reasons: e.g., to give management applications a choice of
management interfaces or different management agents might each serve different functions
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Basic Network Management Components      Management Systems
(Network) Management System (NMS) I.
Network Management System (NMS)
• a collection of tools for network monitoring and control
• designed to view the entire network as a unified architecture
• providing an interface with a powerful but user-friendly set of commands
• the network active elements provide regular feedback of status information to the network control center(s)
• one or more network control centers can be used
• centralized vs. hierarchical vs. distributed layout
Paradoxical situation:
• to work properly, a NMS needs a network that works properly so that management applications and managed network can talk to each other
• without this, it would be impossible to exchange management commands and management information
• of course, for the network to work properly, a proper NMS needs to be employed
Basic Network Management Components      Management Systems
(Network) Management System (NMS) II.
Centralized Layout
o the NMS resides on a single computer system
o may be backed up by another system for High Availability purposes but may reside on multiple computer systems as well
o e.g., to distribute the load - one center is idle or collecting statistics, while the other is used for control
Ludek Matyska  (FI MU)
managed device
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Basic Network Management Components      Management Systems
(Network) Management System (NMS) II.
Hierarchical Layout I.
o the NMS resides on multiple management servers o one system acts as the central server o other systems working as clients = intermediate managers (management proxies)
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Basic Network Management Components     Management Systems
(Network) Management System (NMS) II.
Management Proxies o the systems that play both agent and manager roles simultaneously o the system plays the agent role in interacting with the NMS, but it plays the manager role in interacting with the other network element(s) multiple levels of hierarchy are possible
Ludek Matyska (FI MU)
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Hierarchical Layout II. - Management Proxies
Basic Network Management Components      Management Systems
(Network) Management System (NMS) II.
Distributed Layout
o combines the centralized and hierarchical architectures the NMS uses multiple peer network management systems o each peer controls/monitors a part of the network
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Basic Network Management Components      Management Network
Management Network
o managing systems and managed systems need to be interconnected o == Management Network
o a management network and a production network can: o be physically separate (dedicated) networks
serial interface (direct or through terminal servers) o network interface (Ethernet or any other dedicated network)
o share the same physical network
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Basic Network Management Components      Management Network
Management Network
Dedicated vs. Shared management and production networks I.
Basic Network Management Components      Management Network
Management Network
Dedicated vs. Shared management and production networks II.
Advantages of dedicated management network:
o Reliability - since the management traffic is carried independently of the production traffic, the management becomes significantly more reliable
o e.g., network congestion/failure will not make a certain segment out of reach o Interference avoidance - the management traffic does not compete with other networking (production) traffic
o important when high QoS requirements have to be satisfied in the production network
o although management traffic is not very high in volume, it may be bursty and
still of non-negligible volume o (it might involve downloading large files with new configurations or software images to network elements, etc.) o interference between management and production network traffic can also make certain problems harder to diagnose Security - a dedicated mgmt network is harder to attack and easier to secure o == less prone to hackers and less vulnerable to, e.g., DoS attacks on the production network
Ease of network planning - (production) network planning becomes easier if there is no need to consider management traffic
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Basic Network Management Components      Management Network
Management Network
Dedicated vs. Shared management and production networks III.
Disadvantages of dedicated management network:
o Cost and overhead - a dedicated management network requires a separate network to be built
o the dedicated network requires additional devices, additional space, and
additional cabling ° == significant additional cost
o No reasonable alternative - sometimes, a shared network might realistically be the only option
o e.g., the equipment deployed at the customer side might be reachable only through one network (DSL lines, etc.)
Question: What about a management of the dedicated management network?
• i.e., to have a "management management network"
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Basic Network Management Components      Management Support Organization
Management Support Organization I.
Organizational (non-technical) aspects of network management, e.g.:
o Establishment of process and operational policies, documentation of operational procedures
o helps to make the management consistent and efficient especially in cases of emergencies may include:
o well-defined workflows to make sure that things that are supposed to
happen do not fall through cracks o well-defined escalation procedures to ensure responsiveness
etc.
Collection of audit trails
• automatic logging the activities of management support staff □ who initiated what action, and at what time makes it easier to reproduce what happened and how to recover from situations in which human error or omission led to operational failures
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Basic Network Management Components      Management Support Organization
Management Support Organization II.
Organizational (non-technical) aspects of network management cont'd.: o Network documentation
o the network itself should be documented (and up-to-date!) o important for network planning o e.g., planning the SW updates
o also enables to identify discrepancies between what is supposed to be in the network and what actually has been deployed
o Reliable backup and restore procedures
allows to bring the network back up in case of disasters or emergencies o e.g., restoring the last configuration that was known to work properly
Security emphasis
o the most significant threats to the network might be lead from disgruntled employees on the inside
o employees have physical access to the network equipment
etc.
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Basic Network Management Components     Basic Components Refined
Basic Components of Network Management Refined
Management	«5 ■» » a o '■■
Support	
Organization	
Management Technology
Management Systems       Zjp -5- i (User Proxies) -                                P )		
Management Protocols "Rules of Conversation"		
	Management f~ Network	
		
Management Agents (Real-World Proxies)      1-l~L		3
Real Production      r        ^ r
World ^Netwod^j ^-g) j.-j,
User Concern
Network Devices
Figure: Basic Parts of the Network Management - Refined.
Luděk Matyska (FI MU)
2. Network Management
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Simple Network Management Protocol (SNMP)
Lecture overview
l) Motivation
2f Network Management
• Network Management by ISO
3^ Basic Network Management Components
• Network Elements Management Systems Management Network Management Support Organization
• Basic Components Refined
4) Simple Network Management Protocol (SNMP) Structure of Management Information Management Information Base (MIB) Simple Network Management Protocol (SNMP)
bI Conclusion
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Simple Network Management Protocol (SNMP)
Network Management Protocol
Two competing standards:
o OSI CMISE/CMIP (Common Management Service Element/Common Management Information Protocol)
o de jure standards derived from the OSI framework o implementation issues have limited its use
SNMP (Simple Network Management Protocol) o de facto standards based on TCP/IP
o both standards define, how multiple devices in a network can exchange messages for the purpose of network management
including what information can be passed between the devices for this purpose
o at the present time, the SNMP is winning the battle
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Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP) I.
Simple Network Management Protocol (SNMP)
o a tool (protocol) that allows for remote and local management of items on the network including servers, workstations, routers, switches, and other managed devices
• application-level "protocol"
• more than a protocol — it's a framework consisting of a number of architectural components that define how management information is structured, stored, and how it is exchanged using the SNMP protocol itself
o SNMP history:
o SNMP derived from its predecessor SGMP (Simple Gateway Monitoring Protocol) (RFC 1028)
• SNMPvl (1988) - poor security (authentication only by a "community string", transmitted in cleartext)
o SNMPv2 (1993) - improvements in the areas of performance, security, confidentiality, and manager-to-manager communications
o several variants - SNMPv2c (community-based security), SNMPv2u (user-based security), and SNMPv2 (party-based security)
currently - SNMPv3 (1999)
makes no changes to the protocol aside from the addition of cryptographic security - encryption, message integrity, and authentication
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Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP) II.
Simple Network Management Protocol (SNMP) cont'd. o uses the Manager - Agent approach
o proxy managers are also supported (from SNMPv2)
Agent variables
o main SNMP advantages:
o standardized
o universally supported
o extendible
o portable
o allows distributed management access
o lightweight
o both simple framework architecture & simple agent implementations on NEs
Ludek Matyska (FI MU)
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Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
Components
role of SNMP:
o defines the format of messages (packets) exchanged by management systems and agents role of SMI (Structure of Management Information):
o rules specifying the format used to define objects managed on the network that the SNMP protocol accesses
o defines general rules for naming objects, defining object types (including range and length), and showing how to encode objects and values role of MIBs (Management Information Bases):
o collections of named objects, their types, and their relationships to each other in an entity to be managed
Ludek Matyska (FI MU)
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Simple Network Management Protocol (SNMP)
The task of network management may be compared to the task of writing a computer program:
o before one writes a program, the syntax of the language (such as C or Java) must be predefined
o including the structure of variables (simple, structured, pointer, etc.) and
how the variables must be named o in network management, these rules are defined by SMI
o most computer languages require variables to be declared in a program □ the declaration names each variable and defines the predefined type o in network management, this is defined by MIB
o MIB names each object and defines the type of the objects
o the type is a type defined by SMI
once variables are declared, the program needs to write statements to store values in the variables and change them if needed
in network management, this task is done by SNMP
o it stores, changes, and interprets the values of objects already declared by MIB according to the rules defined by SMI
Ludek Matyska  (FIMU) 2. Network Management Spring 2011        40 / 64
Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
Overview
o when a manager wants to send a message to an agent station to find the number of UDP user datagrams received:
o MIB is responsible for finding the object that holds the number of the UDP
user datagrams received o SMI, with the help of another embedded protocol, is responsible for
encoding the name of the object o SNMP is responsible for creating a message, called GetRequest, and encapsulating the encoded message
The object has an integervalue and is called udplnDatagram with id 1.3.6.1.2.1.7.1.0
|---------"-fl^l
Retrieve the value of an object with code 06 09..........
Encapsulate the request in a GetRequest message
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Simple Network Management Protocol (SNMP)     Structure of Management Information
Structure of Management Information (SMI)
Structure of Management Information (SMI)
o currently version 2 (SMIv2) o functions:
o to name objects
o to define the type of data that can be stored in an object
o to show how to encode data for transmissions over the network
	Object attributes		
			
1		1	
Name	Type		Encoding method
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Simple Network Management Protocol (SNMP)     Structure of Management Information
Structure of Management Information (SMIv2)
Naming objects I. Object Name
o to name objects globally, SMI uses an object identifier, which is a hierarchical identifier based on a tree structure
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Simple Network Management Protocol (SNMP)      Structure of Management Information
Structure of Management Information (SMIv2)
Naming objects II.
o = OlDs (Object IDentifiers)
o each object can be defined using a sequence of integers separated by dots
□ e.g., 1.3.6.1.2.1
o this representation is used by SNMP or using a sequence of textual names separated by dots o e.g., iso.org.dod.internet.mgmt.mib-2 this representation is used by people
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Simple Network Management Protocol (SNMP)      Structure of Management Information
Structure of Management Information (SMIv2)
Object type
Object Type
the type of data stored in the object
o to define the data type, SMI makes use of Abstract Syntax Notation 1 (ASN.1) definitions
o and adds some new definitions
o ASN.1 - a standard and flexible notation that describes data
structures for representing, encoding, transmitting, and decoding data
o two categories of object types: simple and structured
o structured data types created by: sequence and sequence of operators o sequence - a list of (arbitrary) data fields (~ a record/structure in
computer programming) o sequence of - an array of data fields or records (sequences)
by a combination of simple and structured data types, new structured data types can be created
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Simple Network Management Protocol (SNMP)      Structure of Management Information
Structure of Management Information (SMIv2)
Object type - Simple data types
Type	Size	Description
INTEGER	4 bytes	An integer with a value between -23' and 231 - 1
Integer32	4 bytes	Same as INTEGER
Unsigned32	4 bytes	Unsigned with a value between 0 and 232 - 1
OCTET STRING	Variable	Byte string up to 65,535 bytes long
OBJECT IDENTIFIER	Variable	An object identifier
IPAddress	4 bytes	An IP address made of four integers
Counter32	4 bytes	An integer whose value can be incremented from 0 to 232; when it reaches its maximum value, it wraps back to 0.
Counter64	8 bytes	64-bit counter
Gauge32	4 bytes	Same as Counter32, but when it reaches its maximum value, it does not wrap; it remains there until it is reset
TimeTicks	4 bytes	A counting value that records time in ^ s
BITS		A string of bits
Opaque	Variable	Uninterpreted string
Ludek Matyska  (FI MU) 2. Network Management Spring 2011        46 / 64
Simple Network Management Protocol (SNMP)      Structure of Management Information
b. Sequence of (simple variables)
		...	1
c. Sequence			
			
			
• • •			
		...	
d. Sequence of (sequences)
Ludek Matyska  (FI MU)
2. Network Management
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Simple Network Management Protocol (SNMP)      Structure of Management Information
Structure of Management Information (SMIv2)
Encoding method
Encoding method
o the Basic Encoding Rules (BER) standard is used to encode data to be transmitted over the network
o in order to be understood by both communicating parties uniformly
o BER specifies that each piece of data can be encoded in triplet format: tag, length, and value
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Simple Network Management Protocol (SNMP)      Structure of Management Information
Structure of Management Information (SMIv2)
Encoding method - Tag I.
Encoding method - Tag
o 1-byte field that defines the type of data o composed of three subfields:
o class - universal (00), applicationwide (01), context-specific (10), or private (11)
o universal - data types taken from ASN.1 o applicationwide - data types added by SMI
o context-specific - data types having the meanings that may change
from one protocol to another o private - data types that are vendor-specific
o format - simple (0) or structured (1)
o number - further divides simple or structured data into subgroups
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Simple Network Management Protocol (SNMP)     Structure of Management Information
Structure of Management Information (SMIv2)
Encoding method - Tag II.
Data Type	Class	Format	Number	Tag (Binary)	Tag (Hex)
INTEGER	00	0	00010	00000010	02
OCTET STRING	00	0	00100	00000100	04
OBJECT IDENTIFIER	00	0	00110	00000110	06
NULL	(){)	0	00101	00000101	05
Sequence,sequence of	00	1	10000	00110000	30
IPAddress	01	0	00000	01000000	40
Counter	01	0	00001	01000001	41
Gauge	01	0	00010	01000010	42
TimeTicks	01	0	0001 1	01000011	43
Opaque	01	0	00100	01000100	44
Ludek Matyska  (FI MU)
2. Network Management
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Simple Network Management Protocol (SNMP)      Structure of Management Information
Structure of Management Information (SMIv2)
Encoding method - Length
Encoding method - Length
o 1 or more bytes field
o 1-byte == the most significant bit must be 0
o the other 7 bits define the length of the data o more-bytes == the most significant bit of the first byte must be 1
o the other 7 bits of the first byte define the number of bytes needed to define the length
0	0	0	0	0	0	1	0
a.The colored part defines the length (2).
1 |0|0|0|0|0|1 | 0 |  |o|o|o|o|o|o|o|i |  |0|0|0|0|0|1 | 0 | 0
b.The shaded part defines the length of the length (2 bytes); the colored bytes define the length (260 bytes).
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Simple Network Management Protocol (SNMP)      Structure of Management Information
Structure of Management Information (SMIv2)
Encoding method - Examples I.
o INTEGER with a value 14
02	04	00	00	00	0E
00000010	00000100	00000000	00000000	00000000	00001110
Tag Length Value (14)
(integer) (4 bytes)
o OCTET STRING with a value "HI"
04	02	48	49
00000100	00000010	01001000	01001001
Tag	Length	Value	Value
(String)	(2 bytes)	(H)	(1)
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Simple Network Management Protocol (SNMP)      Structure of Management Information
Structure of Management Information (SMIv2)
Encoding method - Examples II.
o ObjectIdentifier with a value 1.3.6.1
06	04	01	03	06	01
00000110	00000100	00000001	00000011	00000110	00000001
Tag Length Value Value Value Value
(Objectld) (4 bytes) (1) (3) (6) (1)
|-«-1.3.6.1 (iso.org.dod. internet)-
o IPAddress with a value 131.21.14.8
40 04 83 15 OE 08
01000000	00000100	10000011	00010101	00001110	00001000
Tag	Length	Value	Value	Value	Value
(IPAddress)	(4 bytes)	(131)	(21)	(14)	(8)
		U-	-131.21.14.8 -		
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SimpleNetwork ManagementProtocol (SNMP)      Structure ofManagement Information
Structure of Management Information (SMIv2)
Object example:
ipInDelivers OBJECT-TYPE SYNTAX Counter32 ACCESS read-only STATUS current DESCRIPTION
,,The total number of input datagrams successfully delivered to IP user-protocols (including ICMP)'' ::= { ip 9 }
2. Network Management
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Simple Network Management Protocol (SNMP)      Management Information Base (MIB)
Management Information Base (MIB)
Management Information Base (MIB)
o a virtual database used for managing the entities in a communications network • organized in a global MIB tree o each MIB (module) represents a sub tree of this global MIB tree
o defines the properties of managed objects within a device to be managed (a router, switch, etc.)
each managed device keeps a database of values for each of the definitions written in the MIB it supports
every device that supports SNMP must also
support a generic MIB-2 module
device manufacturers are allowed to define their own device-specific MIBs
o remember: the standard describing how to create a MIB =>- SMI(v2)
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Simple Network Management Protocol (SNMP)      Management Information Base (MIB)
2. Network Management
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Simple Network Management Protocol (SNMP)      Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
o uses both SMI and MIB to allow the network management o it allows:
o a manager to retrieve the value of an object defined in an agent
o the agent responses with the value o a manager to store a value in an object defined in an agent
o the agent informs about the success/failure or responses with the newly set value
o an agent to send an alarm message about an abnormal situation to the manager
o SNMPv3 defines eight types of packets (PDUs):
o GetRequest, GetNextRequest, GetBulkRequest, SetRequest, Response, Trap, InformRequest, and Report
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Simple Network Management Protocol (SNMP)     Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
Communication Architecture Scheme
Ludek Matyska (FI MU)
2. Network Management
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Simple Network Management Protocol (SNMP)      Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
Protocol Data Units (PDUs) == Types of Packets
Ludek Matyska  (FI MU)
2. Network Management
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Simple Network Management Protocol (SNMP)      Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
Protocol Data Units' (PDUs') Format
PDU				
				VarBind list
				
PDU type	Request ID	Error status	Error index	
Variable		Value	* * ♦	Variable		Value
o Request ID - a sequence number used by the manager in a request and repeated by the agent in a response
o allows to match a request and a corresponding response
o Error Status - an integer used only in response PDUs to indicate an error reported by an agent
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Simple Network Management Protocol (SNMP)      Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
Protocol Data Units' (PDUs') Format - Codes for PDU Type field
Data	Class	Format	Number	Whole Tag (Binary)	Whole Tag (Hex)
GetRequest	10		00000	10100000	AO
GetNextRequest	10		00001	10100001	Al
Response	10		00010	10100010	A2
SetRequest	10		00011	10100011	A3
GetBulkRequest	10		00101	10100101	A5
InformRequest	10		00110	10100110	A6
Trap (SNMPv2)	10		00111	10100111	A7
Report	10		01000	10101000	A8
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Conclusion
Lecture overview
Motivation
\letwork Management
* Network Management by ISO
Basic Network Management Components • Network Elements
Management Systems
Management Network 9 Management Support Organization 9 Basic Components Refined
Simple Network Management Protocol (SNMP)
Structure of Management Information Management Information Base (MIB)
Simple Network Management Protocol (SNMP)
Conclusion
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Conclusion
Network Management - Recapitulation
o Network Management by ISO - FCAPS model
o Fault management, Configuration management, Accounting management, Performance management, Security management
o basic network management components
o Network Elements - contain management interfaces (provided by agents)
o Management Network -dedicated vs. shared network o Network Management System - centralized, distributed, or hierarchical layout
o Management Support Organization - non-technical aspects of network management
o Simple Network Management Protocol (SNMP) manager-agent approach o « a framework - involves SMI, MIB, and other components o objects identified by identifiers (OIDs), each object has a type (defined
by SMI)
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Conclusion
Network Management - Further Information
FI courses:
o PV090: UNIX - Seminar of System Management (dr. Kasprzak)
o PV065: UNIX - Programming and System Management I. (dr. Kasprzak)
PV077: UNIX - Programming and System Management II. (dr. Kasprzak) o PV175: MS Windows Systems Management I. (Bc. Dusek et al.) o PV176: MS Windows Systems Management II. (Mgr. BukaC et al.)
etc.
(Used) Literature:
o A. Farrel: Network Management: Know It All. Morgan Kaufmann, 2009. o A. Clemm: Network Management Fundamentals. Cisco Press, 2006. o B. Forouzan: Data Communications and Networking, 4 th edition. McGraw-Hill, 2007.
M. Subramanian: Network management: principles and practice.
Addison-Wesley, 2000.
o J. R. Burke: Network Management: Concepts And Practice, A Hands-On Approach. Pearson Education, 2008. etc.
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