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Saad Haj Bakry, PhD, CEng, FIEE 1
SNMP: Simple Network SNMP: Simple Network Management ProtocolManagement Protocol
Saad Haj Bakry, PhD, CEng, FIEE
PRESENTATIONS IN NETWORK MANAGEMENTPRESENTATIONS IN NETWORK MANAGEMENT
Saad Haj Bakry, PhD, CEng, FIEE 2
Objectives / ContentsObjectives / Contents
SNMP Principles
SNMP Information RepresentationSNMP OperationRemarks
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 3
SNMP PrinciplesSNMP Principles
IntroductionComponentsMulti-Vendor PrinciplesInformation FlowFramework
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 4
Introduction to SNMPIntroduction to SNMP For TCP/IP Networks:
– Internet / Extranet /Intranet(multi-vendor distributed networks)
First issued in 1989– Developed by IEFT (Internet Research Task Force)
Subsidiary of IAB (Internet Architecture Board)– Supported by 70 vendors
SNMPv3: 1998 Widely implemented / with (+)
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 5
SNMP ComponentsSNMP Components
Managed Node
SNMPManagement
Station
Router AgentBridge Agent
Printer AgentHost Agent
Managed Node
Managed NodeManaged
Node
Management Process
LAN
A Computer Running Management Software (with GUI)
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 6
SNMP Multi-Vendor PrinciplesSNMP Multi-Vendor Principles
An Agent for Every Managed Node – to run SNMP management process
Variables (Objects)– to describe the state of each device
Information (Format) Specification– ANS-1: Standard Object Definition Language
– SMI: Defines (SNMP) Data Structures
– MIB: Data Structure for (Variables) Objects (Uses SMI)
– BER: Basic Encoding Rule (transfer syntax)
(sequence of bytes for transmission)
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 7
SNMP Information FlowSNMP Information Flow
Managed Node
DevicesDevicesDevice
Agent ObjectObjectObjectObjectObjectObject
Variables to describe devices
MIB Data
Structure Modules
Using SMI (ASN-1) Rules to Describe Objects (Variables)
Sequence of Bytes
for Transmission
Using BERRules to Convert SMI
Data Structures into a Sequence of Bytes
SNMP Operations
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 8
SNMP FrameworkSNMP Framework
SMI: Structure of Management Information(Rules of describing management information)
Sub-Super-Set of: ASN-1: Abstract Syntax Notation One
MIB: Management Information Base
(Database on managed devices)
BER: Basic Encoding Rules
Protocol: “Manager-Agent” interaction
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 9
SNMP Information SNMP Information RepresentationRepresentation
SMI: Structure of Management Information
MIB: Management Information Base
BER: Basic Encoding Rules
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 10
SMI Data Types SMI Data Types (Examples)(Examples)
Primitive Data
Types
INTEGER A 32-bit integer
BIT STRING A string of 0 or more bits
OCTET STRING A string of 0 or more bytes
NULL A variable with no value (place holder)
OBJECT IDENTIFIER
An officially defined data type (based on standards)
Additional Types
User Defined Types Application Specific
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 11
SMI: OBJECT IDENTIFIER SMI: OBJECT IDENTIFIER (1/2)(1/2)
Top Level ccitt (0) iso (1) iso-ccitt (2)
org (3)
dod (6)
Internet (1)
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 12
Internet (1)
mgmt (2) private (4) security (5)
mib-2 (1)
mgmt (2): Standard objects
registered by IANA
(Internet Assigned Number
Authority)system (1) interfaces (2) ip (4)
{Internet (1) 2 1} = {1 3 6 1 2 1}
SMI: OBJECT IDENTIFIER SMI: OBJECT IDENTIFIER (2/2)(2/2)
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 13
MIB: Definitions of Objects MIB: Definitions of Objects
MIB is the definition of “objects” that should be provided on each managed node by the SNMP “agent”.
An “object” is a quantity or a field that describes one functional aspect of a device.
MIB objects arearranged in “groups” Some groups relate
to “layer” of the protocol stack.
Other groups relate to the system as a “whole”
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 14
SNMP MIB ArchitectureSNMP MIB Architecture
Simple Network Management Protocol
SNMP
MIB ApplicationMIB TCP / UDPMIB ICMP
IPMIB
MIB ARPMIB Data LinkMIB Physical
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 15
Internet ProtocolsInternet Protocols
Application User Interface: E-mail / http / ftp /…
TCP / UDP Transmission Control Protocol
User Data-gram Protocol
ICMP Internet Control Message Protocol
Address Resolution Protocol
Internet Protocol: Addressing / Routing / Congestion Control
IPARP
Data Link Point-to-Point Control: LAN / WAN
Physical Communication Interface: T-R / Links
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 16
BER StructureBER Structure
Every value transmitted consists of up to 4 fields: The identifier
identifies the item that follows The length
of the data field in bytes The data field End-of-contents
flag, if the data length is unknown
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 17
BER Structure: BER Structure: The IdentifierThe Identifier
2-bits 1-bit 5-bits
Tag / Type
00 universal
01 application
10 context specific
11 private
Data Type
0primitive
1constructed
Value
Identification Number
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 18
BER Structure: BER Structure: ExamplesExamples
00000010 00000001 00110001
00000011 00000010 01111000 01111001
Identifier Length Value
Integer: 49
String “xy”
78
(Hex)
79
(Hex)
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 19
SNMP OperationSNMP Operation
PrinciplesManager-Agent InteractionBasic Messages
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 20
SNMP Operation PrinciplesSNMP Operation Principles
Asynchronous (Request-Response) Operation– to run SNMP management process
SNMP Trap– An “agent” notices a significant event and report the
event to its management stations Trap Directed Polling
– Polling at “long intervals”, with
– Acceleration on receipt of a trap.
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 21
SNMP OperationSNMP Operation
Managed Node
Agent
Management Station
Request PDU
Response PDU
PDU: Protocol Data Unit
Time
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 22
Basic MessagesBasic Messages (1/2)(1/2)
Originator: Manager / Receiver: Agent Get-request: Requests the value of one or more
variables Get-next-request: Requests the value of the next
variable (Alphabetically through MIB) Get-bulk-request: Requests large transfer (such
as Tables) Set-request: Updates one or more variables
Requesting & Updating Variable Values
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 23
Basic MessagesBasic Messages (2/2)(2/2)
Originator: AgentReceiver: Manager Response-PDU:
Response Message Trap-PDU:
Trap Report
Originator: ManagerReceiver: Another
Manager Inform-request
Local MIB Description
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 24
RemarksRemarks
SNMP Given Review:
Principles
Information
Operation
Future Work:
Practical Systems
Using SNMP
Practical Work
Follow Up
SNMP: Simple Network Management Protocols
Saad Haj Bakry, PhD, CEng, FIEE 25
ReferencesReferences Perkins, D.T., RMON: Remote Monitoring of
SNMP-Managed LANs, Prentice Hall PTR, Upper Saddle River, New Jersey, 1999
Stalling, W., SNMP, SNMPv2, and CMIP: The Practical Guide to Network Management Standards, Addison-Wesley, Reading Massachusetts, 1993
“Specification of Abstract Syntax Notation One (ASN.1)”, ISO 8824, December 1987.
SNMP: Simple Network Management Protocols