1 chapter 3 basic foundations: standards, models, and language network management: principles and...
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1
Chapter 3
Basic Foundations:Standards, Models, and Language
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
And
Chapter 13Network Management Applications
2
Notes
Introduction
• Standards• Standards organizations• Protocol standards of transport layers• Protocol standards of management
(application) layer• Management Models• Language
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
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Table 3.1 Network Management Standards
Standard Salient Points
OSI / CMIP
(Common Management Information Protocol)
International standard (ISO / OSI)
Management of data communications network - LAN and WAN
Deals with all 7 OSI layers
Most complete
Object oriented – classes, inheritance
Well structured and layered
Consumes large resource in implementation – complex
SNMP / Internet
(Simple Network Management Protocol)
Industry standard (IETF)
Originally intended for management of Internet components, currently adopted for WAN and telecommunication systems
Easy to implement – uses scalar objects
Most widely implemented
TMN
(Telecom Management Network)
International standard (ITU-T)
Management of telecommunications network – service providers
Based on OSI network management framework
Addresses both network and administrative aspects of management – Service and Business Management
IEEE IEEE standards adopted internationally
Addresses LAN and MAN management
Adopts OSI standards significantly
Deals with first two layers of OSI RM – Physical and Data Link
Web-based Management
Web-Based Enterprise Management (WBEM) – spec by DMTF
Java Management Extensions (JMX) – called earlier JMAPI
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Notes
OSI NM Architecture and Model
Network Management: Principles and Practice© Mani Subramanian 2000
NetworkMangement
InformationModel
OrganizationModel
FunctionalModel
CommunicationModel
Figure 3.1 OSl Network Management Model
• Organization model• Network management components
• object, agent, and manager• Functions of components• Relationships
• Information model• Structure of management information (SMI)
• Syntax and semantics• Management information base (MIB)
• Organization of management information• Object-oriented
Chapter 3
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Notes
OSI NM Architecture and Model
Network Management: Principles and Practice© Mani Subramanian 2000
NetworkMangement
InformationModel
OrganizationModel
FunctionalModel
CommunicationModel
Figure 3.1 OSl Network Management Model
• Communication model• Transfer syntax with bi-directional messages
• M-SET, M-GET• Transfer structure (PDU)
• Functional model – User oriented requirements of NM• Application functions (Covered in chapter 13)
• Configure components (CM)• Monitor components (FM)• Measure performance (PM)• Secure information (SM)• Usage accounting (AM)
Chapter 3
6
Notes
SNMP Architecture and Model(Not defined explicitly)
Network Management: Principles and Practice© Mani Subramanian 2000
NetworkMangement
InformationModel
OrganizationModel
FunctionalModel
CommunicationModel
Figure 3.1 OSl Network Management Model
• Organization model• Same as OSI model
• Information model• Same as OSI, but scalar
•Communication model• Messages less complex than OSI and unidirectional (request, response)• Transfer structure (PDU)
• Functional model• Application functions in terms of
• Operations (get, set)• Administration – who has access to what• Security – community-based
Chapter 3
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Network Management: Principles and Practice© Mani Subramanian 2000
TMN Architecture• Addresses management of telecommunication
networks
• Based on OSI model
• Superstructure on OSI network
• Addresses network, service, and business
management
• See chapter 11 for more details
Chapter 3
Business Management
Service Management
Network Management
Element Management
Managed Network Element
q3
q3
q3
q3
Figure 11.11 TMN Service Architecture
8
Example (NMF)
BusinessManagement
CustomerService
Management
ServiceManagement
Service MgmtTarif/Charging
Service MgmtProvisioning
Service MgmtOther
NetworkManagement
Net MgmtRouting Admin
Net MgmtTraffic Admin
Net MgmtRestoration
ElementManagement
Net ElementCust Admin
Net ElementSwitch Mgmt
Net ElementTrans Eqpt
Mgmt
ServiceDetails
Performance andBilling Data
ServiceConfiguration
Service-impacting
Events
EquipmentConfiguration
EquipmentAlarms
Q3
Q3
Q3
TMN LogicalLayered Architecture
Physical Realization ofTMN Architecture
Figure 11.14 TMN Realization Example (NMF)
q3Ref. Point
q3Ref. Point
q3Ref. Point
Chapter 11
Network Management: Principles and Practice© Mani Subramanian 2000
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Network Management: Principles and Practice© Mani Subramanian 2000
Organization Model• Manager
• Manages the managed elements• Sends requests to agents, retrieves management information & stores it in MDB• Monitors alarms – unsolicited traps/notifications from agents• Houses applications, e.g., CM, FM, etc.• Provides user interface, e.g., HPOpenview
• Agent• Gathers information from objects – get• Configures parameters of objects – set• Responds to managers’ requests – response• Generates alarms and sends them to managers (unsolicited) – trap
• Managed object• Network element that is managed, e.g., hubs, bridges, etc.• Houses management agent – process running• All objects are either not managed or manageable (more expensive)
Chapter 3
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Notes
Manager
Managed objects
Unmanaged objects
Figure 3.2 Two-Tier Network Mangement Organization Model
Agent process
MDB
MDB Management Database
Network Management: Principles and Practice© Mani Subramanian 2000
Two-Tier Model
• Agent built into network element Example: Managed hub, managed router• A manager 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)
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Notes
Agent / Manager
Managed objects
Agent process
Manager
Figure 3.3 Three-Tier Network Mangement Organization Model
MDB
MDB
MDB Management Database
Network Management: Principles and Practice© Mani Subramanian 2000
Three-Tier Model
• Middle layer plays the dual role• Agent to the top-level manager• Manager to the managed objects - e.g., collects data
• Example of middle level: Remote monitoring agent (RMON)
• Examples:• Statistical measurement on a network• Local site passes information to a remote site
Chapter 3
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Notes
MoM
Agent
Agent NMSManager
Managed objects
Managed objects
Figure 3.4 Network Mangement Organization Model with MoM
Agent process
MDB
MDB MDB
MoM Manager of ManagersMDB Management Database
AgentManager
Agent NMS
Agent
Agent NMSManager
Network Management: Principles and Practice© Mani Subramanian 2000
Manager of Managers
• Agent NMS manages the domain• MoM presents integrated view of domains• Domain may be geographical (cities), administrative (departments), vendor-specific products (Cisco), etc.
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Notes
Manager NMS
Agent NMS
Agent NMS
Manager NMS
Figure 3.5 Dual Role of Management Process
Network Management: Principles and Practice© Mani Subramanian 2000
Peer NMSs
• NMSs configured in a peer-to-peer relationship• Network management system acts as peers• Dual role of both NMSs• Example: Two network service providers exchange Management information• Dumbbell architecture discussed in Chapter 1• Notice that the manager and agent functions are processes and not systems
Chapter 3
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Notes
InteroperabilityChapter 1
NMSVendor A
NetworkAgent
NetworkAgent
NetworkObjects
NetworkObjects
NMSVendor B
NetworkAgent
NetworkAgent
NetworkObjects
NetworkObjects
Messages
Services & Protocols
• Message exchange between NMSs managing different domains
Vendor A
(b) Services and Protocols
ApplicationServices
ManagementProtocol
TransportProtocols
Objects
Objects
Vendor B
Objects
Objects
Figure 1.23 Network Management Dumbbell Architecture
Network Management: Principles and Practice© Mani Subramanian 2000
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Notes
Information Model: Analogy
• Information model – Structure & storage of information• Figure in a book uniquely identified by
• ISBN, Chapter, and Figure number in that hierarchical order
• ID: {ISBN, chapter, figure} – Hierarchy of designation• The three elements above define the syntax – format• Semantics is the meaning of the three entities according to Webster’s dictionary• The information comprises syntax and semantics about an object
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
• Management information model =objects representation (SMI) +management information of objects (MIB)
• SMI defines the syntax & semantics of management information stored in the MIB• Information model specifies the information base to describe managed objects and their relationships (i.e., MIB)
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Notes
Structure of Management Information (SMI)
Network Management: Principles and Practice© Mani Subramanian 2000
• SMI defines for a managed object:• Syntax• Semantics – i.e., definition • 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
Chapter 3
• Uses ASN.1: Abstract Syntax Notation One
• See RFC 1155:• Section 4. Managed objects• Section 4.3. Macros
17
Notes
Management Information Base (MIB)
Network Management: Principles and Practice© Mani Subramanian 2000
• Used by manager & agents to store & exchange
management information• Information base contains information about objects• Organized by grouping of related objects (e.g., IP group)• Defines relationship between objects (e.g., object system
is a parent of object sysDescr)• It is NOT a physical database. It is a virtual
database that is compiled into management module
Chapter 3
• The agent MIB is used for accessing local information requested by the manager, and sending a response back
• The manager MIB is used for accessing information on all network components the manager manages.
• See RFC 1213
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Notes
Information Base View: An Analogy
Network Management: Principles and Practice© Mani Subramanian 2000
• 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
Chapter 3
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Notes
MIB View and Access of an Object
Network Management: Principles and Practice© Mani Subramanian 2000
• A managed object has many attributes - its information base (e.g., IPAddress, # of ports)• There are several operations that can be performed on the objects (get, set)• A user (manager) can view and perform only certain operations on the object by invoking the management agent – privileges depends on the user and the managed object• The view of the object attributes that the agent perceives is the MIB view• The operation that a user can perform is the MIB access
Chapter 3
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Notes
Network Management: Principles and Practice© Mani Subramanian 2000
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 (for processes to exchange information)
• 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
Figure 3.6 Network Configuration with Data and Information Base
Chapter 3
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Notes
Managed Object
Network Management: Principles and Practice© Mani Subramanian 2000
• Managed objects can be• Network elements (hardware, system)
• hubs, bridges, routers, transmission facilities• Software (non-physical)
• programs, algorithms• Administrative information
• contact person, name of group of objects (IP group)
Chapter 3
• In fact, any type of info that can be included in theMIB can be managed.
22
Notes
Root
Level 1
Level 2
Level 3
Figure 3.7 Generic Representation of Management Information Tree
Network Management: Principles and Practice© Mani Subramanian 2000
Management Information TreeChapter 3
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Notes
iso-itu2
itu0
iso1
org3
dod6
internet1
Figure 3.8 OSI Management Information Tree
Network Management: Principles and Practice© Mani Subramanian 2000
OSI Management Information Tree
• iso International Standards Organization itu International Telecommunications Union dod Department of Defense• Designation:
• iso 1• org 1.3• dod 1.3.6• internet 1.3.6.1 – all internet managed
objects will start with this
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Notes
• Type
• Name
• Syntax
• Definition
• Status
• Access
• Instance
Object Type and Instance
• Example of a circle• “circle” is syntax• Semantics is definition from dictionary “A plane figure bounded by a single curved line, every point of which is of equal distance from the center of the figure.”
• Analogy of nursery school
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Notes
Managed Object: Internet Perspective
object ID unique ID
and descriptor and name for the objectsyntax used to model the objectaccess access privilege to a managed object
status implementation requirements
definition textual description of the semantics of object type
Network Management: Principles and Practice© Mani Subramanian 2000
Object Type:Object ID and
Descriptorcircle
Access:Access
privilege
Defintion :Semantics -
textual description
Status :Implementaionrequirements
Syntax :model of object
Figure 3.9(a) Internet Perspective
Chapter 3
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Notes
object class managed object
attributes attributes visible at its boundary
operations operations which may be applied to it
behaviour behaviour exhibited by it in response to operation
notifications notifications emitted by the object
Network Management: Principles and Practice© Mani Subramanian 2000
Behaviour
Object Class:Circularobject
Obj
ect C
lass
:El
liptic
alob
ject
Attributes :circle, dimension
Operations:Push
Attributes:ellipse, dimension
Notifications :Notify changes ina ttribute values
Figure 3.9(b) OSI Perspective
Managed Object: OSI Perspective
Chapter 3
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Notes
Characteristics Example
Object type PktCounter
Syntax Counter
Access Read-only
Status Mandatory
Description Counts number of packets
Figure 3.10(a) Internet Perspective
Characteristics Example
Object class Packet Counter
Attributes Single-valued
Operations get, set
Behavior Retrieves or resets values
Notifications Generates notifications on newvalue
Figure 3.10 (b) OSI Perspective
Figure 3.10 Packet Counter As Example of Managed Object
Packet Counter Example
Network Management: Principles and Practice© Mani Subramanian 2000
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Notes
Internet Vs OSI Managed Object
Network Management: Principles and Practice© Mani Subramanian 2000
• Scalar object in Internet vs. Object-Oriented approach in OSI• OSI characteristics of operations, behavior, and notification are part of communication model in Internet: get/set and response/alarm• Internet syntax is absorbed as part of OSI attributes• Internet access is part of OSI security model• Internet status is part of OSI conformance application• OSI permits creation and deletion of objects; Internet does not. However, enhancement in SNMPv2 include:
• Defining new data types• Adding or deleting conceptual rows in tables
Chapter 3
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Notes
Mgmt. Communication Model
Manager Agent
Operations /Requests
Responses
Notifications /Traps
ApplicationsNetwork Elements /Managed Objects
Figure 3.11 Management Message Communication Model
Network Management: Principles and Practice© Mani Subramanian 2000
• In Internet requests/responses, in OSI operations• In Internet traps and notifications (SNMPv2), in OSI notifications
Chapter 3
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Notes
Transfer Protocols
ManagerApplications
ManagerCommunication
Module
Transport Layers
AgentApplications
AgentCommunication
Module
Transport Layers
Physical Medium
Operations / Requests / ResponsesTraps / Notifications
SNMP (Internet)CMIP (OSI)
UDP / IP (Internet) OSI Lower Layer Profiles (OSI)
Figure 3.12 Management Communication Transfer Protocols
Network Management: Principles and Practice© Mani Subramanian 2000
• Internet is based on SNMP; OSI is based on CMIP• OSI uses CMISE (Common Management Information Service Element) application with CMIP• OSI specifies both c-o and connectionless transport protocol; SNMPv2 extended to c-o, but rarely used
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Notes
Abstract Syntax Notation One
Network Management: Principles and Practice© Mani Subramanian 2000
• ASN.1 is more than a syntax; it’s a formal language• Addresses both syntax and semantics• Two type of syntax
• Abstract syntax: set of rules that specify data type and structure for information storage• Transfer syntax: set of rules for communicating information between systems
• Makes application layer protocols independent of lower layer protocols• Can generate machine-readable code: Basic Encoding Rules (BER) is used in management modules
Chapter 3
• ASN.1 developed jointly by ITU-T and ISO • Abstract syntax → Information model
• Transfer syntax → communication model
32
Notes
Backus-Nauer Form (BNF)Definition:
<name> ::= <definition>
Rules:
<digit> ::= 0|1|2|3|4|5|6|7|8|9
<number> ::= <number> | <digit> <number>
<op> ::= +|-|x|/
<SAE> ::= <number>|<SAE>|<SAE><op><SAE>
Example:• 9 is primitive 9• 19 is construct of 1 and 9• 619 is construct of 6 and 19
• BNF is used for ASN.1 constructs• Constructs developed from primitives• The above example illustrates how numbers
are constructed from the primitive <digit>• Simple Arithmetic Expression entity (<SAE>) is
constructed from the primitives <digit> and <op>
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Notes
Simple Arithmetic Expression
Network Management: Principles and Practice© Mani Subramanian 2000
<SAE> ::= <number> | <SAE><op><number>
Example: 26 = 13 x 2
Constructs and primitives
Chapter 3
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Notes
Type and Value
Network Management: Principles and Practice© Mani Subramanian 2000
• Assignments• <BooleanType> ::= BOOLEAN• <BooleanValue> ::= TRUE | FALSE
• ASN.1 module is a group of assignmentsperson-name Person-Name::=
{
first "John",
middle "I",
last "Smith"
}
Chapter 3
• Two basic parameters associated with an entity (e.g., BOOLEAN)
• Data type• Value (assigned to this data type)
• Keywords: entities with all capital letters (e.g., TRUE)
35
Notes
Data Type: Example 1
Network Management: Principles and Practice© Mani Subramanian 2000
• Module name starts with capital letters• Tags uniquely identify a data type• Data types:
• Primitives: NULL, GraphicString• Constructs
• Alternatives : CHOICE• List maker: SET, SEQUENCE• Repetition: SET OF, SEQUENCE OF
• Difference between SET and SEQUENCE
Chapter 3
PersonnelRecord ::= SET{ Name, title GraphicString, division CHOICE { marketing [0] SEQUENCE
{Sector, Country},
research [1] CHOICE{product-based [0] NULL, basic [1] NULL},
production [2] SEQUENCE{Product-line, Country } } }
etc.
Figure 3.13 ASN.1 Data Type Definition Example 1
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Notes
Data Type: Example 2
Network Management: Principles and Practice© Mani Subramanian 2000
• SET– No order required– Order not important– Data types should all be distinct
• SEQUENCE– The order in the list is maintained
• SEQUENCE OF SEQUENCE makes tables of rows
Trade-message ::= SEQUENCE {invoice-no INTEGER name GraphicString, details SEQUENCE OF SEQUENCE {part-no INTEGER quantity INTEGER}, charge REAL, authenticator Security-Type} Security-Type ::= SET { … … … }
Figure 3.14 ASN.1 Data Type Definition Example 2
Chapter 3
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Notes
Modules
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
Formal Definition:
<module name> DEFINITIONS ::= BEGIN<name> ::= <definition><name> ::= <definition>END
Example:
RFC1213 DEFINITIONS ::= BEGIN……END
• A module is a group of assignments.
• Modules can be imported into and exported from other modules.
38
Notes
ASN.1 SymbolsSymbol Meaning
::= Defined as
| or, alternative, options of a list
- Signed number
-- Following the symbol are comments
{} Start and end of a list
[] Start and end of a tag
() Start and end of subtype
.. Range
Network Management: Principles and Practice© Mani Subramanian 2000
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Notes
• CHOICE
• SET
• SEQUENCE
• OF
• NULL
Keyword Examples
• Keywords are in all UPPERCASE letters
Network Management: Principles and Practice© Mani Subramanian 2000
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Notes
ASN.1 Data Type Conventions
Data Types Convention Example
Object name Initial lowercase letter sysDescr, etherStatsPkts
Application data type Initial uppercase letter Counter, IpAddress
Module Initial uppercase letter PersonnelRecord
Macro, MIB module All uppercase letters RMON-MIB
Keywords All uppercase letters INTEGER, BEGIN
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Notes
Data Type: Structure & Tag
Data Type
OtherTaggedStructuredSimple
Number
Tag
Structure
Class
Universal ApplicationContext-specific
Private
Figure 3.15 ASN.1 Data Type Structure and Tag
Network Management: Principles and Practice© Mani Subramanian 2000
• A Data Type is defined based on a structure and a tag
• Structure defines how data type is built
• Tag uniquely identifies the data type
Chapter 3
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Notes
Structure
Network Management: Principles and Practice© Mani Subramanian 2000
• Simple• PageNumber ::= INTEGER• ChapterNumber ::= INTEGER
• Structured / Construct• BookPageNumber ::=
SEQUENCE {ChapterNumber, Separator, PageNumber}
Example: {1-1, 2-3, 3-39}• Tagged
• Derived from another type; given a new ID• In Fig. 3-14, INTEGER could be either universal or application specific
• Other types: • CHOICE, ANY
• BookPages ::= SEQUENCE OF { BookPageNumber}or
BookPages ::= SEQUENCE OF{SEQUENCE {ChapterNumber, Separator, PageNumber}}
Chapter 3
43
Notes
Tag
Network Management: Principles and Practice© Mani Subramanian 2000
• Tag uniquely identifies a data type• Comprises class and tag number• Class:
• Universal - always true• Application - only in the application used• Context-specific - specific context in application• Private - used extensively by commercial vendors
• Example (RFC 1155):• IpAddress ::= [APPLICATION 0] IMPLICIT OCTET STRING (SIZE (4))• Counter ::= [APPLICATION 1] IMPLICIT INTEGER (0..4294967295)
Example: BOOLEAN Universal 1 INTEGER Universal 2 research [Application 1] (Figure 3.13) product-based Context-specific under research [0]
Chapter 3
44
Notes
Enumerated Integer
• ENUMERATED is a special case of INTEGER
• Does not have INTEGER semantics → Arithmetic operations should not be performed on enumerated values.
• Example: RainbowColors (5) is orange
RainbowColors ::= ENUMERATED
{
violet (0)
indigo (1)
blue (2)
green (3)
yellow (4)
orange (5)
red (6)
}
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
Example From the SNMP MIB (RFC 1157):
ErrorStatus ::=INTEGER {
noError (0),tooBig (1),noSuchName (2),badValues (3),readOnly(4),genErr (5)}
45
Notes
Subtype Data Type
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
• A subtype data type is derived from a parent type.
Example:
PageNumber ::= INTEGER (0..255)
→ Limits the maximum page number to 255
Example (RFC 1213):
sysDescr OBJECT-TYPESYNTAX DisplayString (SIZE (0..255))ACCESS ……
46
Notes
ASN.1 Module Example
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
IpNetToMediaEntry ::= SEQUENCE {
ipNetToMediaIfIndex INTEGER,
ipNetToMediaPhysAddress PhysAddress,
ipNetToMediaNetAddress IpAddress,
ipNetToMediaType INTEGER}
• An entry of the address translation table in SNMP IP MIB (RFC 1213) is the following:
47
Name: John P Smith Title: Director Employee Number 51 Date of Hire: 17 September 1971 Name of Spouse; Mary T Smith Number of Children 2 Child Information Name Ralph T Smith Date of Birth 11 November 1957 Child Information Name Susan B Jones Date of Birth 17 July 1959
(a) Informal description of personnel record ---------------------------------------------------------------------------------------------------------
PersonnelRecord ::= [APPLICATION 0] IMPLICIT SET { Name, title [0] VisibleString, number EmployeeNumber, dateOfHire [1] Date, nameOfSpouse [2] Name, children [3] IMPLICIT SEQUENCE OF ChildInformation DEFAULT { } } ChildInformation ::= SET { Name, dateOfBirth [0] Date } Name ::= [APPLICATION 1] IMPLICIT SEQUENCE { givenName VisibleString, initial VisibleString, familyName VisibleString } EmployeeNumber ::= [APPLICATION 2] IMPLICIT INTEGER Date ::= [APPLICATION 3] IMPLICIT VisibleString -- YYYYMMDD
(b) ASN.1 description of the record structure ---------------------------------------------------------------------------------------------------------
{ {givenName “John”, initial “T”, familyName “Smith”}, title “Director” number “51” dateOfHire “19710917” nameOfSpouse {givenName “Mary”, initial “T”, familyName “Smith”}, children { { {givenName “Ralph”, initial “T”, familyName “Smith”}, dateOfBirth “19571111”}, { {givenName “Susan”, initial “B”, familyName “Jones”} dateOfBirth “19590717”}}}
(c) ASN.1 description of a record value
Network Management: Principles and Practice© Mani Subramanian 2000
ASN.1 Example from ISO 8824Chapter 3
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Notes
Object Name
• Example from RFC 1155:
internet OBJECT IDENTIFIER ::= {iso(1) org(3) dod(6) 1}
iso-itu2
iso1
itu0
org3
dod6
internet1
private4
enterprise1
IBM2
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Notes
TLV Encoding
• ASN.1 syntax containing management info is encoded using the BER (Basic Encoding Rules) → defined for the transfer syntax.
• ASCII text data is converted to bit-oriented data.
• TLV: Type, Length, and Value are components of the structure.
• Length: of the Value field in number of octets.
• Value: is encoded based on the data type.
Type Length Value
Class(7-8th bits)
P/C(6th bit)
Tag Number(1-5th bits)
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
Class 8th bit 7th bit Universal 0 0 Application 0 1 Context-specific 1 0 Private 1 1
P/C bit:0: primitive1: construct
50
TLV Encoding- INTEGER
• INTEGER: Universal 2• Type: 00000010 [Class (00), P/C (0), Tag (00010)]• Length:
• If Value length ≤ 127 → Use 1 octet (with b8 = 0)• If Value length > 127 → Use >1 octet (with b8 = 1)
First octet indicates number of octets that follow to specify the Value length. Example: 128 → 10000001 10000000
• Value:• If Value > 0 (always MSB = 0 → add more octets if needed)
Example: 255 → 00000000 11111111• If Value < 0 → twos-complement
Takes the absolute value and inverts all 1s to 0s and all 0s to 1s, then adds 1. Example: -5 → 11111011
• Example: TLV for 255→ 00000010 00000010 00000000 11111111
Type Length Value
Class(7-8th bits)
P/C(6th bit)
Tag Number(1-5th bits)
Class 8th bit 7th bit Universal 0 0 Application 0 1 Context-specific 1 0 Private 1 1
Network Management: Principles and Practice© Mani Subramanian 2000
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P/C bit:0: primitive1: construct
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Notes
TLV Encoding- OCTET STRING
• OCTET STRING: Universal 4
• Type: 00000100 [Class (00), P/C (0), Tag (00100)]
• Length: Number of octets in Value.
• Value: Binary representation of string.
• Example: TLV for ‘0C1B’ →00000100 00000010 00001100 00011011
Type Length Value
Class(7-8th bits)
P/C(6th bit)
Tag Number(1-5th bits)
Class 8th bit 7th bit Universal 0 0 Application 0 1 Context-specific 1 0 Private 1 1
Network Management: Principles and Practice© Mani Subramanian 2000
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P/C bit:0: primitive1: construct
52
Notes
Macro
• Macro is used to create new data types• TYPE NOTATION → defines the syntax of new types• VALUE NOTATION → defines the syntax of new values
<macroname> MACRO ::=
BEGIN
TYPE NOTATION ::= <syntaxOfNewType>
VALUE NOTATION ::= <syntaxOfNewValue>
<auxiliaryAssignments>
END
CS8803 OBJECT-IDENTITY STATUS current DESCRIPTION "A graduate-level network
management course offered every fall by College of Computing in Georgia Institute of Technology."
::= {csclasses 50}
Network Management: Principles and Practice© Mani Subramanian 2000
Example:
Chapter 3
Macro from RFC 2578 (SMIv2):
OBJECT-IDENTITY MACRO ::=BEGIN
TYPE NOTATION ::="STATUS" Status"DESCRIPTION" TextReferPart
VALUE NOTATION ::= value (VALUE OBJECT IDENTIFIER)Status ::= "current" | "deprecated" | "obsolete“ReferPart ::= "REFERENCE" Text | empty Text ::= value(IA5String)
END
53
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 3
Part II
Chapter 13Network Management Applications
54
Notes
Network and Systems Mgmt
Networked Information Systems
BusinessManagement
ServiceManagement
NetworkManagement
SystemManagement
ElementManagement
ResourceManagement
NetworkElements
SystemResources
Figure 13.1 Network and System Management
• TMN architecture expanded to include systems management
Network Management: Principles and Practice© Mani Subramanian 2000
Chapter 13
55
Notes
Functional Model
OSIFunctional Model
FaultManagement
ConfigurationManagement
PerformanceManagement
SecurityManagement
AccountingManagement
Network Management: Principles and Practice© Mani Subramanian 2000
• Configuration management• Set and change network configuration and component parameters• Network provisioning• Inventory management• Network topology• Set up alarm thresholds
• Fault management• Detection and isolation of failures in network• Trouble ticket administration
• Performance management• Monitor performance of network
• Security management• Authentication• Authorization• Encryption
• Accounting management• Functional accounting of network usage
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Network Provisioning(Configuration Management)
• Provisioning of network resources• Design• Installation and maintenance
• Circuit provisioning in telephone industry• Circuit-switched network• Automated process
• Provisioning for packet-switched network based on:• Performance statistics• QoS requirements• Example: Provisioning of links is based on average and peak demands
• ATM networks• Permanent virtual circuit (PVC)• Switched virtual circuit (SVC)
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Inventory Management(Configuration Management)
• Inventory Management of:• Equipment • Facilities
• Efficient Database system:
• Indices and keys for easy access and search• Characteristics of components• Status of components
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Network Topology(Configuration Management)
• Manual• Filter parameters → impose constraints• Auto-discovery by NMS using
• Broadcast ping• ARP table in devices (e.g., local router)
• Mapping of network• Layout• Layering
• Views• Physical• Logical
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Traditional LAN ConfigurationHub 1
Hub 2
A1
Router
Port BSegment B
Port ASegment A
A2
B1
B2
Router
Segment A / Hub 1
A2A1
Segment B / Hub 2
B2B1
Figure 13.2 LAN Physical Configuration
Figure 13.3 Logical Configuration of Two LAN Segments
• One-to-one mapping between physical and logical configuration
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Virtual LAN Configuration
• Physical and logical configurations different• Physical location obtained from System group
Hub 1
Hub 2
A1
Router
B1
A2
B2
Switch
Port A / Segment APort A / Segment B
Figure 13.4 VLAN Physical Configuration
Segment B
Segment A
Segment B
Segment A
Router
Segment A / Hub 1 & 2
A2 (Hub 2)A1 (Hub 1)
Segment B / Hub 1 & 2
B2 (Hub 2)B1 (Hub 1)
switch
Figure 13.5 Logical Configuration of Two VLAN Segments
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Fault Management• Fault is a failure of a network component
• Results in loss of connectivity
• Fault management involves a 5-step process:1. Fault detection
• Polling• Traps: linkDown, egpNeighborLoss
2. Fault location• Detect all components that failed and trace
down the tree topology to where the problem starts
3. Restoration of service (has higher priority)4. Fault isolation
• Identification of root cause of the problem• Fault isolation by network and SNMP tools
to determine source of problem → Trouble ticket generated
• Use artificial intelligence /correlation techniques
5. Problem resolution → Trouble ticket closed
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Performance Management
• Tools
• Performance Metrics
• Data Monitoring (e.g., RMON)
• Problem Isolation (process similar to FM)
• Performance Statistics
• Tools:• Protocol analyzers• RMON• MRTG
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Performance Metrics
• Macro-level• Throughput• Response time• Availability• Reliability
• Micro-level• Bandwidth• Utilization• Error rate• Peak load• Average load
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• Macro-level parameters can be defined in terms of micro-level parameters
• Response time depends on both network and system performance.
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Data Monitoring and Problem Isolation
• Data monitoring• Normal behavior• Abnormal behavior (e.g., excessive collisions, high packet loss, etc)• Set up traps (e.g., parameters in alarm group in RMON on object identifier of interest)• Set up alarms for criticality• Manual and automatic clearing of alarms
• Problem isolation• Manual mode using network and SNMP tools• Problems in multiple components needs tracking down the topology• Automated mode using correlation technology
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Performance Statistics
• Traffic statistics• Error statistics• Used in
• QoS tracking• Performance tuning • Validation of SLA• Trend analysis• Facility planning• Functional accounting
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• Statistics require large amount of data sampling → overhead traffic on the network.
• One solution is RMON → Collecting statistical data is done locally → Improves overall network performance.
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Security Management
• Security threats• Policies and Procedures• Resources to prevent security breaches• Firewalls• Cryptography• Authentication and Authorization• Client/Server authentication system• Message transfer security• Network protection security
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Security Threats (RFC 3414)
ManagementEntity A
ManagementEntity B
Modification of informationMasquerade
Message stream modification
Disclosure
Figure 7.10 Security Threats to Management Information
• Modification of information: Contents modified by unauthorized user, does not include address change• Masquerade: change of originating address by unauthorized user• Message Stream Modification: Fragments of message altered by an unauthorized user to modify the meaning of the message• Disclosure: is eavesdropping. This does not require interception of message• Denial of service and traffic analysis are not considered as threats
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Security Threats
ManagementEntity A
ManagementEntity B
Modification of informationMasqueradeMessage stream modification
Disclosure
Figure 7.10 Security Threats to Management Information
• SNMPv3 addressed security threats using USM (user-based security model)• USM has two modules:
• Authentication module• Data integrity• Data origin
• Privacy module• Data confidentiality• Message timeliness• Message protection
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Policies and ProceduresBasic guidelines to set up policies and procedures:
1. Identify what you are trying to protect.2. Determine what you are trying to protect it from.3. Determine how likely the threats are.4. Implement measures, which will protect your assets in
a cost-effective manner.5. Review the process continuously and make
improvements to each item if a weakness is found.
• References:• Formal statement of rules for protecting organization’s technology and assets (RFC 2196)• Introduction to Firewalls (NIST)• Orange Book by National Computer Security Center (NCSC) rates computers based on security design features
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Accounting Management
• Least developed • Usage of resources• Hidden cost of IT usage• Functional accounting• Business application
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