introduction to snmp

Introduction to SNMP

Yen-Cheng Chen

http://www.im.ncnu.edu.tw/~ycchen/

[email protected]

Contents

1. Basic Concepts

2. Management Information Base

3. Simple Network Management Protocol

4. SNMP Application Examples

5. Reference

Appendix: ASN.1 Concept

3

1. Basic Concepts

InternetInternet

RMONDevice

UNIX....

FDDI

UNIX PC

Firewall/ Router

ManagementStation

ManagementStation

.......

PollingPolling NotificationNotification

....

...

PC UNIX

PC

NMNMNMNM

4

網路管理標準化

如果每個廠商的網路設備均提供一套獨特專屬 (Proprietary) 的網管方法與介面，網路管理工作將很難執行。

網路管理標準化每個網路設備必須提供一致的網路管理介面

( 亦即相同的網路管理通信協定 ) 。

5

網路管理相關標準

Internet SNMPv1, SNMPv2, SNMPv3

ISO/ITU-T X.700 Series: CMIP/S (Common Management Information Protocol /

Service)

ITU-T M.3000 Series: TMN (Telecommunication Management Networks)

SNMP Concepts

SNMP: Simple Network Management Protocol De facto standards of network management for TCP/IP

networks (Internet) IAB recommends all IP & TCP implementations should

be network manageable. That is, all TCP/IP network devices should support

SNMP.

IAB: Internet Activities Board

SNMP Architectural Model

Key Components One or more Management Stations

• Perform management applications, i.e, Monitor & Control.

Multiple Network Elements• hosts, routers, gateways, ..., which each contain an Agent.

Network Management Protocol• Exchange network management information.

SNMP Architectural Model (cont.)

Network

網路介面

SNMP

UDP

IP

網路介面

SNMP

UDP

IP

網路介面

SNMP

UDP

IP

Manager Agent Agent

. . .

ManagementStation Host Router

Network Elements (NEs)

Network Management

Protocol

SNMP

9

Management Components

Manager Agent Network Management Protocol Management Information Base (MIB)

10

Management Components

Management Station (Manager) Network management applications. Provide an interface which the human network manager can m

onitor and control the network. Agent

Network devices should be equipped with agent software so that they can be managed from a management station.

Responds to requests for information from managers. Responds to requests for actions from managers. May asynchronously provide managers with important but uns

olicited information.

11

Management Components (cont.)

Network Management Protocol Communication protocol between managers and agents

NM protocol provides a standard way to exchange management information between managers and agents.

Management Information Base (MIB) A collection of Managed Objects.

The resources to be managed are represented as objects, called Managed Objects (MOs).

Management Information Base (MIB)

Each resource to be managed is represented by an object, called managed object (MO).

The MIB is a structured collection of MOs.

Essentially, each MO is a data variable.

Each agent in an NE maintains an MIB.

Monitor: by reading the values of MOs in the MIB.

Control: by modifying the values of MOs in the MIB.

網路介面

SNMP

UDP

IP

AgentAgent

Managed Resources

MIBMIB

NE: Network Element

SNMP Services Four Services

Get, Set, GetNext, Trap

Five SNMP PDUs GetRequest, SetRequest, GetNextRequest, GetResponse, Trap

Manager Agent(s)

Get, Set, GetNext Request

Get Response

Trap

PDU: Protocol Data Unit

14

SNMP Services

Get Request

Get ResponseManager Agent

GetNext Request


Set Request


Trap RequestManager Agent

Get

GetNext

Set

Trap

Get

GetNext

Set

Trap

SNMP Services (cont.)

Get Request: Retrieve the values of objects in the MIB of an agent.

Get-Next Request: Retrieve the values of the next objects in the MIB of an agent.

Set Request: Update the values of objects in the MIB of an agent.

Trap Request Report extraordinary events to the manager.

Get-Next Request

:Non-Leaf Object

:Leaf Object1 2 3

4 5 6

MIB Tree :In SNMP, Only leaf objects have values.

＊

Default UDP Ports for SNMP

網路介面

SNMP

UDP

IP

Manager

ManagementStation

Network Elements (NEs)

網路介面

SNMP

UDP

IP

Agent

162 Any 161 Any

SNMP Standards

SNMP Protocol (Std 15) RFC1157: Simple Network Management Protocol.

Structure of Management Information (SMI) (Std 16) RFC1155: Structure and Identification of Management

Information for TCP/IP-based Internets. RFC1212: Concise MIB Definitions.

MIB-II (Std 17) RFC1213: Management Information Base for Network

Management of TCP/IP-based Internets: MIB-II.

http://www.isi.edu/rfc-editor/rfc.html

2. Management Information Base

Structure of Management Information (SMI) Set of rules on how managed objects should be defined. Objects are defined using Abstract Syntax Notation One ASN.1

(ITU-T X.208 / ISO 8824)

MIB The collection of all defined objects Contains hierarchically organized variables corresponding to

managed objects. MIB-II, RMON MIB, Bridge MIB, Repeater MIB, X.25 MIB,

FDDI MIB, Token Ring MIB, ...

Object Identifier Object Identifier (OID):

Global identifier for a particular object type. An OID consists of a sequence of integers, which specify the

position of the object in the global object identifier tree. root

ccitt iso joint-iso-ccitt

directory

0 1 2

std regauthority

memberbody

org0

1 2 3

dod

internet

6

1

12 3 4

mgmt experimental private

MIB II

system1

interface2

at3

IP4

ICMP5

TCP6

UDP7

EGP8

Trans.10

SNMP11

1 1enterprises

1.3.6.1.2.1.2 1.3.6.1.4.1

1.3.6.1.2.1

MIB II

interface

enterprises

21

Private MIB Registration

Companies can register their private MIB extensions in the global MIB tree by contacting the Internet Assigned Numbers Authority (IANA). http://www.iana.org/http://www.iana.org/

Currently assigned enterprise subtrees

ftp://ftp.isi.edu/in-notes/iana/assignments/enterprise-numbersftp://ftp.isi.edu/in-notes/iana/assignments/enterprise-numbers

SMI (RFC1155)RFC1155-SMI DEFINITIONS ::= BEGINEXPORTS -- EVERYTHING internet, directory, mgmt, experimental, private, enterprises, OBJECT-TYPE, ObjectName, ObjectSyntax, SimpleSyntax, ApplicationSyntax, NetworkAddress, IpAddress, Counter, Gauge, TimeTicks, Opaque;

internet OBJECT IDENTIFIER ::= { iso org(3) dod(6) 1 }directory OBJECT IDENTIFIER ::= { internet 1 }mgmt OBJECT IDENTIFIER ::= { internet 2 }experimental OBJECT IDENTIFIER ::= { internet 3 }private OBJECT IDENTIFIER ::= { internet 4 }enterprises OBJECT IDENTIFIER ::= { private 1 }

SMI (cont.)OBJECT-TYPE MACRO ::= BEGIN TYPE NOTATION ::=

"SYNTAX" type (TYPE ObjectSyntax) "ACCESS" Access "STATUS" Status VALUE NOTATION ::= value (VALUE ObjectName)

Access ::= "read-only" | "read-write" | "write-only" | "not-accessible" Status ::= "mandatory" | "optional" | "obsolete" END

ObjectName ::= OBJECT IDENTIFIER

ASN.1 Macro

24

OBJECT-TYPE Example

sysDesc OBJECT-TYPE

SYNTAX DisplayString (SIZE (0..255))

ACCESS read-only

STATUS mandary

::= { system 1}

ObjectName ::= OBJECT IDENTIFIER ObjectSyntax ::= CHOICE {

simple SimpleSyntax,application-wide

ApplicationSyntax}

SimpleSyntax ::= CHOICE {

number INTEGER,string OCTET STRING,object OBJECT IDENTIFIER,empty NULL} }

ApplicationSyntax ::= CHOICE {

address NetworkAddress,counter Counter,gauge Gauge,ticks TimeTicks,arbitrary Opaque

}

NetworkAddress ::=CHOICE {

internet IpAddress}IpAddress ::=

[APPLICATION 0]IMPLICIT OCTET STRING (SIZE (4))

Counter ::=[APPLICATION 1]IMPLICIT INTEGER (0..4294967295)

Gauge ::=[APPLICATION 2]IMPLICIT INTEGER (0..4294967295)

TimeTicks ::=[APPLICATION 3]IMPLICIT INTEGER (0..4294967295)

Opaque ::=[APPLICATION 4] IMPLICIT OCTET STRING

END

SMI (cont.)

26

Object Syntax Summary

Simple Syntax Integer Octet String Object Identifier Null

Application Syntax Network Address Counter Gauge Time Ticks Opaque

Concise MIB Definition (RFC 1212)

OBJECT-TYPE MACRO ::=BEGINTYPE NOTATION ::= "SYNTAX" type(ObjectSyntax) "ACCESS" Access "STATUS" Status

DescrPart ReferPart IndexPart DefValPartVALUE NOTATION ::=

value (VALUE ObjectName)

DescrPart ::="DESCRIPTION" value (description DisplayString)

| emptyReferPart ::=

"REFERENCE" value (reference DisplayString)| empty

IndexPart ::="INDEX" "{" IndexTypes "}" | empty

IndexTypes ::=IndexType | IndexTypes "," IndexType

IndexType ::=value (indexobject ObjectName) | type (indextype)

DefValPart ::="DEFVAL" "{" value (defvalue ObjectSyntax) "}"

| emptyEND

Examples: MIB II (RFC 1213)mib-2 OBJECT IDENTIFIER ::= { mgmt 1 }system OBJECT IDENTIFIER ::= { mib-2 1 }interfaces OBJECT IDENTIFIER ::= { mib-2 2 }at OBJECT IDENTIFIER ::= { mib-2 3 }ip OBJECT IDENTIFIER ::= { mib-2 4 }icmp OBJECT IDENTIFIER ::= { mib-2 5 }

tcp OBJECT IDENTIFIER ::= { mib-2 6 } udp OBJECT IDENTIFIER ::= { mib-2 7 } egp OBJECT IDENTIFIER ::= { mib-2 8 } -- cmot OBJECT IDENTIFIER ::= { mib-2 9 }transmission OBJECT IDENTIFIER ::= { mib-2 10 } snmp OBJECT IDENTIFIER ::= { mib-2 11 }

ifEntry OBJECT-TYPESYNTAX IfEntryACCESS not-accessibleSTATUS mandatoryDESCRIPTION

"An interface entry containing objects at the subnetwork layer and below for a particular interface."

INDEX { ifIndex }::= { ifTable 1 }

ifTable OBJECT-TYPESYNTAX SEQUENCE OF IfEntry

ACCESS not-accessibleSTATUS mandatory

DESCRIPTION"A list of interface entries. The number of entries is givenby the value of ifNumber."

::= { interfaces 2 }

29

Identification of Managed Objects

Use Object Identifier (OID) OID = Object Type OID . Instance Identifier Object Type OID:

Each Object type has a unique OID

Instance Identifier: Identify instances of object type

E.g .mib-2.interface.ifTable.ifEntry.ifDescr.2

30

Two Kinds of Managed Objects

Type-Specific Objects: sysDescr OBJECT-TYPE

SYNTAX DisplayString (SIZE(0..255))

::= {system 1}

OID: mib-2.system.1.0 Columnar Objects

OID:mib-2.interface.ifTable.ifEntry.ifDescr.2mib-2.interface.ifTable.ifEntry.ifDescr.6 mib-2.interface.ifTable.ifEntry.ifType.2mib-2.interface.ifTable.ifEntry.ifType.6

31

Columnar Objects

ifTable OBJECT-TYPE SYNTAX SEQUENCE OF IfEntry … ::= { interface 2 }

IfEntry ::= SEQUENCE { ifIndex INTEGER, ifDescr DisplayString, ifType INTEGER, …}

ifEntry OBJECT-TYPE SYNTAX IfEntry … INDEX {ifIndex } ::= { ifTable 1}

ifDescr OBJECT-TYPE SYNTAX DisplayString (SIZE(0..255)) ACCESS read-only STATUS madatory...::= {ifEntry 2}

32

Columnar Objects

ifIndex ifDescr ifType . . .

1 le0 6 . . .

6 llc0 1 . . .

7 lo0 24 . . .

9 le1 6 . . .

.ifTable.ifEntry.1 (1.3.6.1.2.1.2.2.1.1) .ifTable.ifEntry.2 (1.3.6.1.2.1.2.2.1.2)

.ifTable.ifEntry.3 (1.3.6.1.2.1.2.2.1.3)

1.3.6.1.2.1.2.2.1.3.71.3.6.1.2.1.2.2.1.2.6

33

Index in MIB II ifEntry {ifIndex} atEntry {atNetIfIndex, atNetAddress} ipAddrEntry {ipAdEntAddr } ipRouteEntry {ipRouteDest} ipNetToMediaEntry {ipNetToMediaIfIndex,

ipNetToMediaNetAddress} tcpConnEntry

{tcpConnLocalAddress, tcpConnLocalPort, tcpConnRemoteAddress, tcpConnRemotePort}

udpEntry {udpLocalAddress, udpLocalPort} egpNeighEntry {egpNeighAddr}

34

Index Example

To get the state of the TCP connection:10.144.18.118:1200 ===> 10.144.14.40:1600

Use snmp_get_req. to get the “tcpConnState” of the tcpConnTable in MIB II.

tcpConnState ==> .1.3.6.1.2.1.6.13.1.1

.1.3.6.1.2.1.6.13.1.1.10.144.18.118.1200.10.144.14.40.1600

MIB II System Group

Provide general information about the managed system. Interfaces Group

Contains generic information about the physical interfaces. Address-Translation Group

Contains information about the mapping between network addresses and physical addresses for each physical interface.

IP Group Contains information about the implementation and operation of IP at the

managed system. ICMP Group

Contains information about the implementation and operation of ICMP at the managed system.

MIB-II (cont.) TCP Group

Contains information about the implementation and operation of TCP at the managed system.

UDP Group Contains information about the implementation and operation of UDP at

the managed system. EGP Group

Contains information about the implementation and operation of EGP at the managed system.

Transmission Group Provides details about the underlying transmission media for each interface.

SNMP Group Provides the statistics of SNMP operations at the managed system.

IETF MIBs

1213 MIB-II 1316 Character Stream 1317 RS-232-like Hardware 1471 PPP 1513 RMON for Token Ring 1757 RMON 2021 RMON-II .....

3. SNMP SNMP Message

Version Identifier Community Name Protocol Data Unit

The length of SNMP messages should not exceed 484 octets.

Message ::= SEQUENCE {

version INTEGER {version-1(0)},community OCTET STRING,data ANY

}

Version Community SNMP PDU

SNMP Authentication

Community Relationship between an Agent and Managers.

Community Name Used to validate the SNMP messages. SNMP Password. Default ‘Get’ community name: “public”.

Authentication Failure Agent sends “Authentication Failure Trap” to

Manager.

SNMP PDUPDU ::= SEQUENCE {

request-id INTEGER,error-status INTEGER {

noError(0),tooBig(1),noSuchName(2),badValue(3),readOnly(4)genErr(5)},

error-index INTEGER,variable-bindings

SEQUENCE OF {name ObjectName,value

ObjectSyntax}

}

GetRquest :GetNextRequest :

GetResponse :SetRequest :

Trap :

[0] PDU[1] PDU[2] PDU[3] PDU[4] Trap-PDU

Five SNMP PDUs:

PDU: Protocol Data Unit

SNMP PDU (cont.)

PDU type request-id 0 0 variable-bindings

GetRequest, GetNextRequest, SetRequest

PDU type request-id error-status error-index variable-bindings

GetResponse

variable-bindings

name value name value name value. . .

Trap-PDUTrap-PDU ::= [4]

IMPLICIT SEQUENCE {enterprise OBJECT IDENTIFIER,agent-addr NetworkAddress,

generic-trap INTEGER { coldStart(0), warmStart(1), linkDown(2), linkUp(3), authenticationFailure(4), egpNeighborLoss(5), enterpriseSpecific(6)},

specific-trap INTEGER,time-stamp TimeTicks,variable-bindings VarBindList

}

Enterprise: Type of Object generating trap.

Agent Address:Address of object generating trap.

Generic Trap:Generic trap type.

Specific Trap:Enterprise specific trap.

Time Stamp:Time elapsed between the last initialization of the network entity andthe generation of the trap.

Variable Bindings“Interesting” information

PDU type enterprise agent-addr generic-trap variable-bindingsspecific-traptime-stamp

How does a Manager do?

Translates Internal Data to

ASN.1 Format

Sends RequestPDU to Agent

Translates ASN.1 Package to Internal

Data Format

Received ResponsePDU from Agent

NMApplication

NMApplication

Agent

Agent

Manager

How does an Agent do?

Received SNMP Request PDU from Manager

Translates ASN.1Structure to

Internal Data

Maps MIB Variables to

Internal Variables

Sends SNMP Response PDU

to Manager

Translates ResponsePDU to ASN.1

Format

Implement SNMP Request to Set orGet MIB Value

From Manager

To Manager

Agent

Main Loop of Agent Agent waits for an incoming datagram in Port 161 Reads the datagram from UDP and notes the transport

address of the sending entity. Increments the QUANTUM to keep track of the logical

request-id being processed by agent De-serializes the datagram into an ASN.1 structure. If

error occurs, log error and discard packet. The ASN.1 structure is translated into SNMP message. If

error occurs, log error and discard packet. Check on VERSION-NUMBER field. If error occurs, log

error and discard packet.

Main Loop of Agent (cont.) Community name is looked up.

If community is unknown to agent, agent send AUTHENTICATION trap to Manager station in Port 162; log error and discard packet.

Agent loops through list of variables in the request.

If no prototype is found, return a GET-RESPONE with error noSuchName and discard package.

Once prototype is fund, operation is checked against community profile. If mismatch occurs, return get-respone with error noSuchName or readOnly and discard package.

Otherwise, agent invokes access routine to perform the desired operation.

What's New in SNMPv2

No more Trap PDU, 3 New PDUs: getBulkReq, InformReq, SNMPv2-Trap

Added Security 18 Error Status Values SNMPv2 SMI / SNMPv2 MIB M-to-M Communications Table Operations ...

4. SNMP Application Examples SNMP Commands

snmpget [options] node variable [...]• query a node using SNMP Get request

snmpnext [options] node variable [...]• query a node using SNMP GetNext request

snmpwalk [options] node variable • query a node repeatedly using SNMP GetNext/GetBulk requests

snmptrap [-d] [-p port] [-c community] node enterprise agent-addr generic-trap specific-trap time-stamp variable type value [variable type value...]

• issue an SNMP Version 1 Trap options:[-d] [-t timeout] [-r retries] [-p port] [-c community] [-v version]

Example for snmpget>>snmpget -d 10.144.18.118 .1.3.6.1.2.1.1.1.0Transmitted 41 bytes to camry (10.144.18.118) port 161:Initial Timeout: 0.80 seconds 0: 30 27 02 01 00 04 06 70 75 62 6c 69 63 a0 1a 02 0'.....public... 16: 02 18 bc 02 01 00 02 01 00 30 0e 30 0c 06 08 2b .........0.0...+ 32: 06 01 02 01 01 01 00 05 00 -- -- -- -- -- -- -- ................ 0: SNMP MESSAGE (0x30): 39 bytes 2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1) 5: OCTET-STR COMMUNITY (0x4) 6 bytes: "public" 13: GET-REQUEST-PDU (0xa0): 26 bytes 15: INTEGER REQUEST-ID (0x2) 2 bytes: 6332 19: INTEGER ERROR-STATUS (0x2) 1 bytes: noError(0) 22: INTEGER ERROR-INDEX (0x2) 1 bytes: 0 25: SEQUENCE VARBIND-LIST (0x30): 14 bytes 27: SEQUENCE VARBIND (0x30): 12 bytes 29: OBJ-ID (0x6) 8 bytes: .1.3.6.1.2.1.1.1.0 39: NULL (0x5) 0 bytes

Example for snmpget (cont.)Received 69 bytes from camry (10.144.18.118) port 161: 0: 30 43 02 01 00 04 06 70 75 62 6c 69 63 a2 36 02 0C.....public.6. 16: 02 18 bc 02 01 00 02 01 00 30 2a 30 28 06 08 2b .........0*0(..+ 32: 06 01 02 01 01 01 00 04 1c 53 75 6e 20 53 4e 4d .........Sun SNM 48: 50 20 41 67 65 6e 74 2c 20 53 55 4e 57 2c 55 6c P Agent, SUNW,Ul 64: 74 72 61 2d 31 -- -- -- -- -- -- -- -- -- -- -- tra-1........... 0: SNMP MESSAGE (0x30): 67 bytes 2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1) 5: OCTET-STR COMMUNITY (0x4) 6 bytes: "public" 13: RESPONSE-PDU (0xa2): 54 bytes 15: INTEGER REQUEST-ID (0x2) 2 bytes: 6332 19: INTEGER ERROR-STATUS (0x2) 1 bytes: noError(0) 22: INTEGER ERROR-INDEX (0x2) 1 bytes: 0 25: SEQUENCE VARBIND-LIST (0x30): 42 bytes 27: SEQUENCE VARBIND (0x30): 40 bytes 29: OBJ-ID (0x6) 8 bytes: .1.3.6.1.2.1.1.1.0 39: OCTET-STR (0x4) 28 bytes: "Sun SNMP Agent, SUNW,Ultra-1"system.sysDescr.0 : DISPLAY STRING- (ascii): Sun SNMP Agent, SUNW,Ultra-1

Example of snmpwalk

snmpwalk 10.144.18.118 .1.3.6.1.2.1.1system.sysDescr.0 : DISPLAY STRING- (ascii): Sun SNMP Agent, SUNW,Ultra-1

system.sysObjectID.0 : OBJECT IDENTIFIER: .iso.org.dod.internet.private.enterprises.42.2.1.1

system.sysUpTime.0 : Timeticks: (198219958) 22 days, 22:36:39.58

system.sysContact.0 : DISPLAY STRING- (ascii): [email protected]

system.sysName.0 : DISPLAY STRING- (ascii): camry

system.sysLocation.0 : DISPLAY STRING- (ascii): Information Technology Laboratory 3F

system.sysServices.0 : INTEGER: 72 (01001000)B

Example of snmptrap snmptrap -d manager .1.3.6.1.4.1.612.1.1 10.144.18.116 6 99999 0

.1.3.6.1.1 octetstringascii "Trap test"Transmitted 64 bytes to manager (10.144.18.100) port 162: 0: 30 3e 02 01 00 04 06 70 75 62 6c 69 63 a4 31 06 0>.....public.1. 16: 09 2b 06 01 04 01 84 64 01 01 40 04 0a 90 12 74 [email protected] 32: 02 01 06 02 03 01 86 9f 43 01 00 30 13 30 11 06 ........C..0.0.. 48: 04 2b 06 01 01 04 09 54 72 61 70 20 74 65 73 74 .+.....Trap test 0: SNMP MESSAGE (0x30): 62 bytes 2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1) 5: OCTET-STR COMMUNITY (0x4) 6 bytes: "public" 13: V1-TRAP-PDU (0xa4): 49 bytes 15: OBJ-ID ENTERPRISE (0x6) 9 bytes: .1.3.6.1.4.1.612.1.1 26: IPADDRESS AGENT-ADDR (0x40) 4 bytes: 10.144.18.116 (manager2) 32: INTEGER GENERIC-TRAP (0x2) 1 bytes: 6 35: INTEGER SPECIFIC-TRAP (0x2) 3 bytes: 99999 40: TIMETICKS TIME-STAMP (0x43) 1 bytes: 0 (0x0) 43: SEQUENCE VARBIND-LIST (0x30): 19 bytes 45: SEQUENCE VARBIND (0x30): 17 bytes 47: OBJ-ID (0x6) 4 bytes: .1.3.6.1.1 53: OCTET-STR (0x4) 9 bytes: "Trap test"

53

Get System Information

Get “System Group” of MIB II Use get_request or get_next_request

sysDescr .1.3.6.1.2.1.1.1.0

sysObjectID .1.3.6.1.2.1.1.2.0

sysUptime .1.3.6.1.2.1.1.3.0

sysContact .1.3.6.1.2.1.1.4.0

sysName .1.3.6.1.2.1.1.5.0

sysLocation .1.3.6.1.2.1.1.6.0

54

Get Interface Information

Get “Interface Group” of MIB II Repeatedly Use “get_next_request” Note: We don’t know the ifIndex values in i

fTable.First get the next object of .ifTable.ifEntry.0Then repeatedly “get_next”Until the whole subtree is visited.

56

Traffic Monitoring

Get “ifInOctets” and “ifOutOctets” of MIB II Interface Group

t1: C1 t2: C2

(C2 - C1 ) 8

(t2 - t1) Bandwidth 100%Utilization (%) =

6. Reference

The Simple Book, marshall T.Rose, Prentice-Hall Inc. SNMP, SNMPv2 and RMON: The Practical Guide to Network

Management, Willeam Stallings SMI; http://ds.internic.net/rfc/rfc1155.txt Concise MIB Format; http://ds.internic.net/rfc/rfc1212.txt SNMP; http://ds.internic.net/rfc/rfc1157.txt MIB II; http://ds.internic.net/rfc/rfc1213.txt Trap Format; http://ds.internic.net/rfc/rfc1215.txt ASN.1 and BER; ITU-T X.208, X.209

59

Development of SNMP Standards

SNMPv2 SNMPv3 RMON I RMON II

60

SNMPv3 An Architecture for Describing Internet Management

Frameworks Local Processing Model for version 3 of the Simple

Network Management Protocol (SNMPv3) Message Processing and Control Model for version 3 of

the Simple Network Management Protocol (SNMP) User-based Security Model for version 3 of the Simple

Network Management Protocol (SNMPv3) View-based Access Control Model (VACM) for version 3

of the Simple Network Management Protocol (SNMP) User-based Security Model (USM) for version 3 of the

Simple Network Management Protocol (SNMPv3)

61

RMON I & II

introduction to snmp

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