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Course Instructor: Parkash Lohana
USMAN INSTITUTE OF TECHNOLOGYHamdard University
CN506 Network Management
Week 08SPRING 2010
Revision for Mid-Term Exam
Management Scenarios
• Customer Network Management
• Distributed Data Storage
• Central Graphic Archive
• Shared document System
• Help Desk Support
• Nomadic Systems
• DNS Management
• Backup and Archiving System
Management Functions
• Fault management
• Configuration management
• Accounting management
• Performance management
• Security 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 to be faults
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– Repair or replace the failed components
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 performance
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 among components and the status of components themselves during network operation
Requirements for Configuration Management
• The network manager needs the capability to– Identify 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 (software distribution and updating)
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 objects
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 growth if end user activity is known in sufficient detail
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’
authorization to access and manipulate the information
Management Functions
• Performance Management – Functional properties are not enough– Look at Non-functional properties
• Performance Metrics
– Throughput, measured by a number of units of communication performed per unit of time. The unit of communication depends on the layer, type of network, and networking services.
– Examples:
• At the link layer, the number of bytes, that are transmitted per second.
Management Functions
• Performance Metrics (Cont..)
• At the network layer, the number of packets that are routed per second
• At the application layer for a web service, the number of web requests that are serviced per second.
• At the application layer for a voice service, the number of voice calls, or call attempts, that can be processed per hour.
Course Instructor: Parkash Lohana
Management Functions
• Performance Metrics (Cont..)
– Delay, measured in a unit of time. Examples:
• At the link layer, the time that it takes for a byte that is transmitted to reach its destination at the other end of line.
• At the network layer, the time it takes for an IP packet to reach its destination.
Management Functions
– Performance Metrics (Cont..)
• At the application layer for a web service, the time that it takes for a request to reach its destination at the host servicing the request after the request has been issued.
• At the application layer of a voice service, the time it takes to receive a dial tone after you have lifted the receiver.
Course Instructor: Parkash Lohana
Management Functions
• Performance Metrics (Cont..)– Quality is in many ways also performance related
and can be measured differently, depending on the networking services
• At the link layer, the number or percentage of seconds during which errors in transmission occurred.
• At the network layer, the number or percentage of packets dropped
Management Functions
– Performance Metrics (Cont..)
• At the application layer for a web services, the number or percentage of web requests that could not be serviced.
• At the application layer for a voice service, the number or percentage of voice calls that were dropped or abnormally terminated.
Course Instructor: Parkash Lohana
Management Functions
• Performance Management
– Performance management therefore encompasses all the measures required for ensuring that the quality of service conforms to the service level agreement. It includes:
• 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.
Management Functions
• Performance Management (Cont..)
• Evaluating history logs (i.e., records on system activity, error files)
• Processing measurement data and compiling performance reports.
• Carrying out performance and capacity planning.
– Monitors, protocol analyzer, statistics packets, report generators, and modeling tools are some of the typical tool functionalities in performance management.
Course Instructor: Parkash Lohana
Management Functions
• Security Management – Two aspects needs to be distinguished:
• Security of Management– Management itself is secure
• Management of Security– Manages the security of the network
Management Functions
Management Functions
• Security Management – Security of management
• Management operations themselves are secure
– Access to management is restricted to authorized users
– Example: access to the management interfaces of the devices in the network needs to be secured
– Access to the management application themselves needs to be secured properly
– Devices generally authorize on the basis of management application, not on the basis of user of a management application.
Management Functions
• Security Management– Management of Security
• Managing the security of network itself– Online security threats are too common
– Security threats not so much the network, but devices connected to network – PCs of end users, system that host the websites for corporations
– Resources of a company that are worth protecting:
» Information, IT infrastructure, services– Security measures that reflect the results of threat analysis or
security risk analysis are needed to prevent damage and loss
Management Functions
• Security Management– Management of Security
• Typical threats are created by:
– Passive attacks: eavesdropping on information; producing a user profile or theft of information (password, etc.).
Management Functions
• Security Management– Management of Security
• Typical threats are created by:– Active attacks:
» masquerade (i.e., user pretending to be some one else, or spoofing);
» manipulating message sequences by changing the sequence, giving priority to or delaying messages;
» reconfiguration, reprogramming, unauthorized access,
» viruses, Trojan horses, denial-of-service attacks.– Malfunctioning of resources
– Faulty or inappropriate behavior and incorrect response operation. Course Instructor: Parkash Lohana
Management Functions
• Security Management– Breakdown of Security Management Tasks
• Security requirements and goals are established on the basis of threat analyses and the values (resources and services) needing protection.
• The security policies defined ultimately identify the security requirements. Examples are:
– Passwords have to be changed every three weeks– Only second-line managers have access to personnel
data– All attacks on security have to be recorded and followed
up.
Management Functions
• Security Management– Breakdown of Security Management Tasks
• These policies serve as framework for security services needed and consequently implemented.
• Security management therefore comprises:– Conducting threat analyses– Defining and enforcing security policies.– Checking identity (authentication based on signature,
notarization, or certification)
Management Functions
– Breakdown of Security Management Tasks
– Carrying out and enforcing access controls
– Guaranteeing confidentiality (encryption)
– Ensuring data integrity (message authentication)
– Monitoring system to prevent threats to security.
– Reporting on security status and violation or attempted violations.
Course Instructor: Parkash Lohana
OSI Architecture and Model
• Organization• Network management components• Functions of components• Relationships
•Information
• Structure of management information (SMI)• Management information base (MIB)
• Organization of management information
• Object-oriented
NetworkManagement
InformationModel
OrganizationModel
FunctionalModel
CommunicationModel
OSl Network Management Model
SNMP Architecture and Model
• Organization• Same as OSI model
• Information• Same as OSI, but scalar
•Communication• Messages less complex than OSI and unidirectional • Transfer structure (PDU)
• Functions• Application functions
• Operations• Administration• Security
NetworkManagement
InformationModel
OrganizationModel
FunctionalModel
CommunicationModel
OSl Network Management Model
Organizational Model
• Manager• Sends requests to agents• Monitors alarms• Houses applications• Provides user interface
• Agent• Gathers information from objects• Configures parameters of objects• Responds to managers’ requests• Generates alarms and sends them to mangers
• Managed object• Network element that is managed• Houses management agent• All objects are not managed / manageable
Two-Tier Model
• Agent built into network element Example: Managed hub, managed router• An agent can manage multiple elements Example: Switched hub, ATM switch• MDB is a physical database• Unmanaged objects are network elements that are not managed - both physical (unmanaged hub) and logical (passive elements)
Manager
Managed objects
Unmanaged objects
Two-Tier Network Mangement Organization Model
Agent process
MDB
MDB Management Database
Three-Tier Model
• Middle layer plays the dual role• Agent to the top-level manager• Manager to the managed objects
• Example of middle level: Remote monitoring agent (RMON)
Agent / Manager
Managed objects
Agent process
Manager
Three-Tier Network Mangement Organization Model
MDB
MDB
MDB Management Database
Manager of Managers
• Agent NMS manages the domain• MoM presents integrated view of domains• Domain may be geographical, administrative, vendor-specific products, etc.
MoM
AgentAgent NMS
Manager
Managed objects
Managed objects
Network Mangement Organization Model with MoM
Agent process
MDB
MDB MDB
MoM Manager of Managers
MDB Management Database
AgentAgent NMS
Manager
Information Model: Analogy
•Information model is concerned with the structure and the storage of information
•A book is identified by an International Standard Book Number (ISBN) •Figure in a book uniquely identified by
• ISBN, Chapter, and Figure number in that hierarchical order
• ID: {ISBN, chapter, figure}
• The three elements above define the syntax
• Semantics is the meaning of the three entities according to Webster’s dictionary
• The information comprises syntax and semantics about an object
Structure of Management Information (SMI)
• SMI defines for a managed object• Syntax• Semantics• plus additional information such as status
• Example sysDescr: { system 1 } Syntax: OCTET STRING Definition: "A textual description of the entity. " Access: read-only Status: mandatory
Management Information Base (MIB)
• Information base contains information about objects
• Organized by grouping of related objects
• Defines relationship between objects
• It is NOT a physical database. It is a virtual
database that is compiled into management module
Information Base View: An Analogy• Fulton County library system has many branches
• Each branch has a set of books
• The books in each branch is a different set
• The information base of the county has the view (catalog) of all books
• The information base of each branch has the catalog of books that belong to that branch. That is, each branch has its view (catalog) of the information base
• Let us apply this to MIB view
Management Data Base / Information Base
• Distinction between MDB and MIB• MDB physical database; e.g.. Oracle, Sybase• MIB virtual database; schema compiled into management software
• An NMS can automatically discover a managed object, such as a hub, when added to the network• The NMS can identify the new object as hub only after the MIB schema of the hub is compiled into NMS software
Manager
Managed objects
MDB MIB
Agent process
MDB Management DatabaseMIB Management Information Base
Network Configuration with Data and Information Base
SNMP Model • CONCEPT• MANAGEMENT COMPONENTS• SMI• MIB• SNMP
CONCEPT
Concept
• A framework for managing devices in an internet using TCP/IP protocol
• Provides set of fundamental operations for monitoring and maintaining an internet.
• Application level protocol allows it to monitor devices made by different manufacturers installed on different physical networks
Concept
Agent
• A router or host that runs the SNMP server program
• Keeps performance information in database
• Can send a trap to the manager if something unusual occurs.
Manager
• A host that runs the SNMP client program
• Has access to the values in the database
• Management is achieved through simple interaction between manager and agent.
Managers and Agents• Management with SNMP is based on three
basic ideas:– A manager checks an agent by requesting
information that reflects the behavior of the agent
– A manager forces an agent to perform a task by resetting values in the agent database.
– An agent contribute to the management process by warning the manager of an unusual situation.
Management Components
• To do management tasks, SNMP uses other two protocols:– Structure of Management Information (SMI)– Management Information Base (MIB)
SNMP, SMI, and MIB
Components of network management on the Internet
SNMP defines the format of packets exchanged between a manager and
an agent. It reads and changes the status (values) of objects (variables) in
SNMP packets.
Role of SNMP
SMI defines the general rules for naming objects, defining object types (including range and length), and showing how to encode objects and values.
Role of SMI
SMI defines neither the number of objects an entity should manage, nor names the objects to be managed nor defines the association between the objects and their values.
Role of SMI
MIB creates a collection of named objects, their types, and their relationships
to each other in an entity to be managed.
Role of MIB
We can compare the task of network management to the task of writing a program.
1. Both tasks need rules. In network management this is handled by SMI.
2. Both tasks need variable declarations. In network management this is handled by MIB.
3. Both tasks have actions performed by statements. In network management this is handled by SNMP.
An Analogy
SNMP
• There are two approaches for management system to obtain information from SNMP:– Traps– Polling
SNMP Traps
• Traps are unrequested event reports that are sent to a management system by an SNMP agent process. A trap will contain:– Network device name– Time the event happened – Type of event
SNMP Traps
• When a trappable event occurs, a trap message is generated by the agent and 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.
SNMP Traps
• 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
SNMP Traps
• Resources are required on the network device to generate a trap
• When lot of events occurs, the network bandwidth may be tied up with traps– Threshold can be used to help
• Because the network device has a limited view, it is possible the management system has already received the information and the trap is redundant
SNMP Polling
• The network management system periodically queries the network device for information
• The advantage is the network management system is in control and know the “big picture”
SNMP Polling
• The disadvantage is the amount of delay from when an event occurs to when it’s noticed– Short interval, network bandwidth is wasted– Long interval, response to event is too slow
SNMP Traps/Polling
• When an event occurs, the network device generates simple traps
• The management system than polls the network device to get the necessary information.
• The management system also does low frequency polling as a backup to the trap
SNMP
• SNMP uses both SMI and MIB in internet network management. – A manager to retrieve the value of an object
defined in an agent. – A manager to store a value in an object
defined in an agent.– An agent to send alarm message about an
abnormal situation to the manager.
SMI
• The Structure of Management Information is a component for network management. Its functions are:– To name objects– To define the type of data that can be stored
in an object.– To show how to encode data for transmission
over the network.
The Structure of Management Information
• Managed object need not be just network element
• Example: “internet” with OBJECT IDENTIEIER 1.3.6.1
• Object type, which is a data type, has a name, syntax, and encoding scheme
Name
• SMI requires that each managed object (such as a router, a variable in a router, a value, etc.) have unique name.
• To name objects globally, SMI uses an object identifier, which is hierarchical identifier based on a tree structure
Naming
• Integer.dot representation
• Name.dot notation
• iso.org.dod.internet.mgmt.mib-2 > 1.3.6.1.2.1
• All objects managed by SNMP are given an object identifier. The object identifier always starts with 1.3.6.1.2.1
Object identifier
All objects managed by SNMP are given an object identifier.
The object identifier always starts with 1.3.6.1.2.1.
Name
Internet Subnodes
mgmt(2)
directory(1)
experimental(3)
private(4)
Internet{1 3 6 1}
Figure 4.13 Subnodes under Internet Node in SNMPv1
Any object in the internet MIB will start with the prefix 1.3.6.1.
There four objects under internet object
SMI
• Object: A textual name, termed descriptor, for the object type along with its corresponding object identifier defined above
• Syntax: The abstract syntax for the object type. It can be a choice of SimpleSyntax (integer, octet string, object identifier, Null) or an ApplicationSyntax, and constructor type
SNMP ASN.1 Data Type
S N M P A S N .1D ata Type
D efinedor
A pplica tion
C onstructor o r
S tructured
S im pleor
P rim itive
N um ber
Tag
S tructure
C lass
U niversa l A pp lica tion C ontext-specific
P riva te
Figure 4.15 SNMP ASN.1 Data Type
Primitive Data Types
Structure Data Type CommentsPrimitive types INTEGER Subtype INTEGER (n1..nN)
Special case: EnumeratedINTEGER type
OCTET STRING 8-bit bytes binary and textual dataSubtypes can be specified byeither range or fixed
OBJECT IDENTIFIER Object position in MIBNULL Placeholder
Defined or Application Data Type
Defined types NetworkAddress Not usedIpAddress Dotted decimal IP addressCounter Wrap-around, non-negative
integer, monotonically increasing,max 2^32 -1
Gauge Capped, non-negative integer,increase or decrease
TimeTicks Non-negative integer inhundredths of second units
Opaque Application-wide arbitrary ASN.1syntax, double wrapped OCTETSTRING
Data types
• Structured Type – By combining simple and structured data
types, can make new structured data types– SMI define two structured data types:
sequence and Sequence of• Sequence. A sequence data type is a combination
of simple data types• Sequence of. A sequence of data type is a
combination of simple data type all of the same type
Constructor or Structured Data Type:
SEQUENCE• List maker
SEQUENCE { <type1>, <type2>,…, <typeN> }
Object OBJECT IDENTIFIER ObjectSyntax1 ipAdEntAddr {ipAddrEntry 1} IpAddress2 ipAdEntIfIndex {ipAddrEntry 2} INTEGER3 ipAdEntNetMask {ipAddrEntry 3} IpAddress4 ipAdEntBcastAddr {ipAddrEntry 4} INTEGER5 ipAdEntReasmMaxSize {ipAddrEntry 5} INTEGER6 ipAddrEntry {ipAddrTable 1} SEQUENCE
List: IpAddrEntry ::= SEQUENCE {
ipAdEntAddr IpAddressipAdEntIfIndex INTEGERipAdEntNetMask IpAddressipAdEntBcastAddr INTEGERipAdEntReasmMaxSize INTEGER (0..65535)
}Managed Object IpAddrEntry as a list
Constructor or Structured Data Type:
SEQUENCE OF
Object Name OBJECT IDENTIFIER Syntax7 ipAddrTable {ip 20} SEQUENCE OF
Table: IpAddrTable ::=SEQUENCE OF IpAddrEntry
Managed Object ipAddrTable as a table
SEQUENCE OF <entry> where <entry> is a list constructor
SMI: Managed Objects
• A managed object has five parameters: – Textual name, syntax, definition, access, and
status as defined in RFC 1155
• Definition: A textual description of the semantics of the object type
• Access: one of read-only, read-write, write-only, or not-accessible
• Status: one of mandatory, optional, or obsolete.
Managed Object: Structure
OBJECT:sysDescr: { system 1 }
Syntax: OCTET STRING Definition: "A textual description of the entity. This value should include the full name and version identification of the system's hardware type, software operating-system, and networking software. It is mandatory that this only contain printable ASCII characters." Access: read-only Status: mandatory
Figure 4.17 Specifications for System Description
Object Identifier
• The first group defines the node administrator:– (1) for ISO
– (2) for CCITT
– (3) for the joint ISO-CCITT
• The second group for the ISO node administrator defines (3) for use by other organizations
• The third group defines (6) for the use of the U.S Department of Defense (DoD)
CCITT
• International Telegraph and Telephone Consultative Committee (CCITT), (from the French name "Comité Consultatif International Téléphonique et Télégraphique") was created in 1956. It was renamed ITU-T in 1993.
Object Identifier
• In the fourth group the DoD has not indicated how it will manage its group so the internet community assumed (1) for its own:
• The fifth group was approved by IAB to be:• (1) for the use of OSI directory in the internet• (2) for object identification for management
purpose• (3) for object identification for experimental
purpose• (4) for object identification for private use.
Encoding Method
• Basic Encoding Rule (BER)
Codes for data typesCodes for data types
Length format
Example. OCTET STRING “HI”
SNMP MIBS
• Management Information Base (MIB) is a collection of related managed objects
• Used to define what information you can get back from the network device
• There are standards and enterprise specific MIBS
MIB
• Each agent has its own MIB
• The objects in the MIB are categorized under ten different groups:– System, interface, address, translation, ip,
icmp, udp, egp, transmission, and smnp.
mib-2
Accessing MIB Variables
• Use the udp group as an example.
• There are four simple variables in the udp group and one sequence of (table of) records.
udp group
Simple variables
• To access any of the simple variable, id of the groups (1.3.6.1.2.1.7) followed by the id of the variable
udpInDatagrams – 1.3.6.1.2.1.7.1
..
udp variables and tables
Table
• So to access the table, we should use the following:
udpTable – 1.3.6.1.2.1.7.5
udpEntry - 1.3.6.1.2.1.7.5.1
udpLocalAddress - 1.3.6.1.2.1.7.5.1.1
udpLocalPort - 1.3.6.1.2.1.7.5.1.2
SNMP MIBS
• Types of MIB Modules– Standard: These are standard MIBS currently
designed to capture the core aspect of particular technology
SNMP MIBS
• Types of MIB Modules– Experimental: Temporary and if achieves
standardization then it is placed in standard module
– Enterprise-specific: Vendor specific MIBS that provide additional management capabilities for those features that require it
SNMP
• A group was formed and their efforts were complete in early 1993
• There are 12 documents describing SNMPv2
• There are three basic commands used with SNMP:– Get– Set– Get next
Types of SNMP packets
• GetRequest– Retrieves the value of a variable or a set of
variable
• GetNextRequest– Used to retrieve values of entries in a table
• GetBulkRequest– Retrieve a large amount of data– Used instead of multiple GetRequest and
GetNextRequest
Types of SNMP packets
• SetRequest– Set(store) a value in a variable
• Response– Response to GetRequest or GetNext
Request; contains values or variable requested
• Trap– Sent from an agent to manager to report an
event
Types of SNMP packets
• InformRequest– Sent from one manager to another remote
manager to get a value of some value from an agents under control of remote manager
• Report – Designed to reports some types of errors
between managers (not currently used)
21.5 SNMP
SNMP is an application program that allows SNMP is an application program that allows 1) a manager to retrieve the value of an object defined in an 1) a manager to retrieve the value of an object defined in an agent; agent; 2) a manager to store a value in an object defined in an 2) a manager to store a value in an object defined in an
agent; agent; and and 3) an agent to send an alarm message about an abnormal 3) an agent to send an alarm message about an abnormal
situation to the managersituation to the manager
The topics discussed in this section include:The topics discussed in this section include:
PDUs PDUs Format Format
SNMP
SNMP PDUs
Overview of PDUs
Example MIB
Get Example
Set
Set Example
Get-Next
Get-Next Example
Trap
Defined Traps
Trap PDU Format
SNMP Message Encoding
SNMP PDU format
Format
• The format for eight SNMP PDU is shown on next slide. The GetBulkRequest PDU differs from the others in two areas as shown in fig.
Format
• The field are listed below:– PDU type. The field define the type of PDU (see
table on next slide)
– Request ID. This field is a sequence number used by the manager in a request PDU and repeated by the agent in a response. It is used to match a request to a response.
– Error status. This is an integer that is used only in response PDU to show the type of errors reported by the agent. Table on slide 12 lists the type of errors that can occur.
Format
• Non-repeaters. This field is used only in GetBulkRequest and replaces the error status field, which is empty in request PDU.
• Error index. The error index is an offset that tells the manager which variable caused the error.
• Max-repetition. This filed is also used in GetBulkRequest and replaces the error index field, which is empty in request PDUs.
• VarBindList. This is a set of variables with corresponding values the manager wants to retrieve or set
Codes for SNMP messagesCodes for SNMP messages
Types of errorsTypes of errors
21.6 MESSAGESMessages
A message in SNMP is made of four A message in SNMP is made of four elements: elements: version, header, security parameters, and version, header, security parameters, and data (which includes the encoded PDU).data (which includes the encoded PDU).
SNMP message
• Any Questions………………..
Network Management Architecture
• The network management platform can use various architectures to provide functionality:– The three most common are:
• Centralized• Hierarchical• Distributed
Centralized Architecture
• The network management platform reside on a single computer
• For a full redundancy, the computer system is backed by another system
• Can allow access and forward events to other consoles on network
Centralized Architecture
• Used for:– All network alerts and events – All network information– Access all management applications
Centralized Architecture
• Pros:– Single location to view events and alerts – Single place to access network management
application and information– Security is easier to maintain
Centralized Architecture
• Cons:– Single system is not redundant or fault
tolerant – As network elements are added, may be
difficult or expensive to scale system to handle load
– Having to query all devices from single location
Hierarchical Architecture
• Uses multiple computer system– One system acting as the central server– Other systems working as clients
• Central server requires backup for redundancy
Hierarchical Architecture
• Key features:– Not dependent on a single system– Distribution of management network tasks– Network monitoring distributed through out
network– Centralized information storage
Hierarchical Architecture
• Pros– Multiple systems to manage the network
• Cons– Information gathering is more difficult and
time consuming– The list of managed devices managed by
each clients needs to be predetermined and manually configured
Distributed Architecture
• Combines the centralized and hierarchical architecture
• Uses multiple peer network management systems– Each peer can have a complete database– Each peer can perform various tasks and
report back to a central system.
Distributed Architecture
• Contains advantages from central & hierarchical architecture– Single location for all network information,
alerts & events. – Single location to access all management
applications– Not dependent on a single system– Distribution of network management tasks– Distribution of network monitoring through out
the network
Network Management Applications
• Goals:– Effectively manage a specific set of devices– Avoid functionality overlap with the platform– Integrate with a platform through the API and
menu system– Reside on multiple platforms
• Application do not share information
Network Management Applications
• Application that exists today– Cisco’s ciscoworks– 3com’s Transcend
Choosing a network management system
• Built from two major components: the platform and applications– A practical approach follows these steps:
• Perform device inventory• Prioritize the functional areas of network
management• Survey network management applications • Choose the network management platform