Network Management System

by Dedi Rahmawan PutraAdvisor: Dr. Kai-Wei Ke

March, 11 2008 1Network Management and Its Application

OutlineNetwork ManagementSimple Network Management Protocol

(SNMP)Structure of Management Information (SMI)Management Information Bases (MIBs)SNMP Manager and Agent(s) Application on

802.16 device



by IETF (for INTERNET)Defining the standard (deciding on the

content)IESG: decides on formal statusImportant area includes :

Operations and ManagementsStandard made by this group:

Simple Network Management Protocol (SNMP)


by ISOimportant for the definition of Network

Management Standarddefined by: ISO-IEC/JTC1/WG4Part of OPEN SYSTEM INTERCONNECTION

(OSI)OSI has little practical functionProtocol defined for management:

CMIP: Common Management Information Protocol

CMIS: Common Management Information Service


by ITU-Tdefined by SG-IVStandard for network made by this group:

TMN: Telecommunication Management Network

Another groups within ITU-T also work on management


Other GroupsDMTF (Distributed Management Task Force)

WBEM: Web Based Enterprise ManagementCIM: Common Information Model

TM-Forum (Tele-Management Forum)Originally based on OSI

OMG (Object Management Group)looking at CORBA for management

IEEE


DifferencesIETF ISO TMN

Management should be simple

Management should be powerful

Define management architecture only

Variable Oriented Approach

Object Oriented Approach

Using OSI protocol (CMIP & CMIS)

Unreliable transport mechanisms

Reliable underlying transport

Management Information is exchanged out-of-band

March, 11 2008 Network Management and Its Application 8

History


starting as temporary solutionmany ideas were copied from OSI

Management framework

COPIED:• Manager-Agent concept• MIBS• ASN.1• TERMINOLOGY

OSI Protocol Copied

OSI introduced new ideasReal object orientation


Simple Network Management Protocol

SNMP Milestone


SGMP SNMPSNMP

SecuritySMPSNMPv2(parties)

SNMPv2(community) SNMPv3

draft fullstandard

proposedstandard

implementationexperience

draft standard

proposed standard

draftstandard

StandardSMI (Structure of Management Information)

Define how management information may look likeSMIv1: RFC 1155SMIv2: RFC2578 (currently used)

MIBs (Management Information Bases)Tell what management information existsMIB-I: RFC1156MIB-II: RFC1213

SNMP (Simple Network Management Protocol)Define how information is exchangedSNMPv1: RFC1157SNMPv2: RFC1901, 1905, 1906SNMPv3: RFC2571-2575


Goals of SNMPUbiquityInclusion of SNMP functionality should be

easySmall codeLimited functionality

Management Extension should be easyManagement Information is modularAdding new MIBs is easy

Management should be robustUsing connectionless transport


Principle Operation


ManagerManager

AgentsAgents

MIBMIB

poll

poll

poll

TRAPS

GET/SET

Transport SNMPv1 : unreliablev2/v3: reliable alternatives

variable

table

SNMP Layering


ManagerManager AgentsAgents

SNMP PDUs

Connectionless Transport Service Provider (UDP)

MIB

REAL VALUE

Manager knowsdefinition

SNMPv1 CommandCommand Operational Result

GetRequest Request the values of one or more MIB variables

GetNextRequest Enables MIB variables to be read sequentially, one variable at a time

SetRequest Permits one or more MIB values to be updated

GetResponse Used to respond to a GetRequest, GetNextRequest, or SetRequest

Trap Indicates the occurence of a predefined condition


SNMPv2 Command (mod. to v1)Command Operational Result

GetBulkRequest Almost similar with GetNextRequest, except it tells the agent to return as much data as possible that can fit into a response message commencing with the next larger value than the requested managed object.

InformRequest Enable the communication between managers.

Response Similar with GetResponse command in SNMPv1, only the the command was renamed.


Remote Monitoring (RMON)An extension of the network manager’s operation.Monitor the data flowing on the remote network

using probe or RMON agents.RMON agents or probe has MIBs (v1:RFC1757;

v2:RFC2021)Overcomes degradation of lower operating rate

WAN bandwidth when monitoring geographically separated networks.

Reduces the amount of information required to be transmitted to NMS.

Reduces the potential bandwidth saturation of the WAN circuit.


RMON Principle Operation


WAN circuit

RMON Agent/ProbeRMON Agent/Probe

Network Management Station

Network Management Station

AgentAgent

MIB

RMON-MIBs


Structure of Management Information and

Management Information Bases

SMIDenotes :

How MIB variables in an MIB are related to one another.

How variables are formatted.Information to obtain the standardization of the MIB.

Additional RFC:1212: concise MIB definition (extends SMIv1)2578: textual convention (definition of new types)

Purpose: to make the definition of new MIBs easierHelp to guide MIB designerDefine the syntaxAllow tools to be built


How Mngmt Information is Stored?Management information within managed

systems may be represented as:SCALAR

eg. Current time, number of packet arrived

Type: integer, character, etc.TABLES

eg. Two dimensional array of scalar.Create a structure of scalars (size can be

dynamic).March, 11 2008 Network Management and Its Application 22

How Mngmt Info. is Exchanged?Can only exchange (a list of) scalars.Cannot read/write a table with an operation.To get a table one should reach each

individual elements (quite complex).


SMI vs. OSIOSI management may have arbitrary structures.OSI supports the retrieval a complete table in

one command.SMI is defined based on 1988 ASN.1 constructs

inherited from OSI.The SMI research group tried to get rid of

ASN.1There’s no OSI standard for that version anymore,

it has been removed from OSIBuilding tools with ASN.1 is relatively difficultSMIv2 improves SMIv1


SMIv2 Data Types of ScalarsSMIv2 SMIv1

SIMPLE TYPES

INTEGER INTEGER

OCTET STRING OCTET STRING

OBJECT IDENTIFIER OBJECT IDENTIFIER

Integer32 -

APPLICATION WIDE TYPES

Unsigned32 -

Gauge32 Gauge32

Counter32 Counter32

Counter64 -

TimeTicks TimeTicks

IpAddress IpAddress

Opaque Opaque

- Network Address

PSEUDOTYPES BITS -


Example of Scalar Object


SNMP

address

name uptimeIpAddress

OCTET STRINGTimeTicks

MANAGERMANAGER AGENTAGENT

Object Naming


1.1

1.2

1.2.1 1.2.2

Object and InstanceObject is the definition of somethingInstance has valueIn scalar, no distinction between object and

instancesBut in terms of table, object may have

multiple instances, multiple rowsThe case of table it’s useful to make

distinctionTo denote the instance, we need to add zero

“0” after the ID of the object to get its valueMarch, 11 2008 Network Management and Its Application 28

Get the value


1.1.0

1.2.1.0 1.2.2.0

Standard Naming Tree


Object Type DefinitionOBJECT-TYPE:

SYNTAX

INTEGEROCTET STRINGOBJECT IDENTIFIERBITSIpAddressInteger32Counter32Counter64Gauge32TimeTicksOpaqueNew Type

MAX-ACCESS

read-onlyread-writeread-createaccessible-for-notifynot-accessible

STATUScurrentdeprecatedobsolete

DESCRIPTION “”


e.g. Definition of Leaf Object-- Definition of address

address OBJECT-TYPE

SYNTAX IpAddress

MAX-ACCESS read-write

STATUS current

DESCRIPTION “Internet Address of this system”

::= {NEW-MIB 1}


e.g. Definition of Non-Leaf ObjectUsing OBJECT IDENTIFIER

Using OBJECT IDENTITY


info OBJECT-IDENTIFIER ::= {NEW-MIB 2}

info OBJECT-IDENTITYSTATUS currentDESCRIPTION “The intermediate node”::= {NEW-MIB 2}

Definition of A MIBNEW-MIB DEFINITIONS ::=

BEGIN

import statement(s)

module identity definition

definition of all node and leaf objects

definition of implementation requirements

END


e.g. Module Identity DefinitionnewMIBModule MODULE-IDENTITY

LAST-UPDATED “200803111600Z”ORGANIZATION “NTUH”CONTACT-INFO ”

National Taiwan University HospitalTaiwan

DESCRIPTION“An Example of MIB Module”

:= {enterprises ntuh(20510) 2}


e.g. Import Statement Definition

IMPORTS

MODULE-IDENTITY, OBJECT-TYPE,

TimeTicks, enterprises

FROM SNMPv2-SMI;


Retrieve Value from Table Entries


Way 1 (not being used by SNMP)

1.3.2.5 = 3

Way 2: X.C.I (used by SNMP)

new-MIB.routeTable.next.8 = 3

destinationdestination

Table IndexingWe also can use GetNext to retrieve table

elements. Index not need to be a consecutive number.Not only Integer, any data type in SMI is

allowed.If index value is not unique:

add more index value which means we add another column to make it unique (multiple indexes).

The formula becomes X.C.I1.I2.


Table Definition-- Definition of the route table

routeTable OBJECT-TYPESYNTAX SEQUENCE OF RouteEntryMAX-ACCESS not-accessibleSTATUS currentDESCRIPTION “This entity’s routing table”::={NEW-MIB 3}

routeEntry OBJECT-TYPESYNTAX RouteEntryMAX-ACCESS not-accessibleSTATUS currentDESCRIPTION “A route to a particular destination”INDEX {dest}::={routeTable 1}


Table Definition (cont. 1)-- Definition of the new type for the row

RouteEntry ::=SEQUENCE{ dest IpAddress,

next IpAddress}


Table Definition (cont. 2)dest OBJECT-TYPE

SYNTAX IpAddressMAX-ACCESS read-onlySTATUS currentDESCRIPTION “The address of a particular destination”::={route-entry 1}

next OBJECT-TYPESYNTAX IpAddressMAX-ACCESS read-writeSTATUS currentDESCRIPTION “The internet address of the next hop” ::={route-entry 2}


Textual ConventionTo refine semantics of existing types.Example:


RunState ::= TEXTUAL CONVENTIONSTATUS currentDESCRIPTION “…”SYNTAX INTEGER {

running (1)runable (2)waiting (3)exiting (4)

}

Notification TypeWith SMIv2 and SNMPv2, there is a

condition defined in MIB which if they happen, lead to a notification at the manager

Example:


linkUp NOTIFICATION-TYPEOBJECTS {ifIndex}STATUS currentDESCRIPTION

“A linkUp trap signifies that the entity has detected that the ifOperStatus object has changed to Up”

::={snmpTraps 4}


MIB-IIDefines the variables to manage the TCP/IP

Protocol Stack.Doesn’t define the layer below IP, nor the

application on the top of transport layer.There are 170 variables being defined in

MIB-II, mostly read-only.Defined based on SMIv1.


Design CriteriaEssential for Fault or Configuration

ManagementOnly weak control objectsSmall number of object are definedAvoid RedundancyEvidence on utilityDo not disturb normal operationNo implementation specific issues


Structure


MIB-II Groups in a Protocol Stack


SYSTEMSYSTEM

TRANSMISSIONTRANSMISSION

INTERFACESINTERFACES

System Group


sysServices


physical layer (e.g. repeaters)

data-link layer (e.g. bridges)

internet layer (e.g. IP routers)

end-to-end (e.g. IP hosts)

application (e.g. nfs servers)

System Group Example sysDescr: Hardware: x86 Family 15 Model 4

Stepping 7 AT/AT COMPATIBLE - Software: Windows 2000 Version 5.1 (Build 2600 Multiprocessor Free)

sysObjectID: 1.3.6.1.4.1.311.1.1.3.1.1

sysUpTime: 37153422 (4 days, 7 h, 12 min, 14.22 s)

sysContact: [email protected]

sysName: DEDI

sysLocation: Lab407-2

sysServices: 76


ConclusionSNMP become the most popular Network

Management System for INTERNET world.The current SNMP used: SNMPv1,

SNMPv2c, and some SNMPv3.The current SMI used: SMIv2The current MIB used: MIB-2


ReferencesAiko Pras, (2000). Internet Management

Protocol, http://www.simpleweb.org . Centre for Telematics and Information Technology, University of Twente, Netherland.

Gilbert Held, (2000). Managing TCP/IP Networks: Technique, Tools and Security Consideration. John Wiley&Sons Ltd.


Documents

Network Management System