SNMP: Simple Network Management Protocol PRESENTATIONS IN NETWORK MANAGEMENT SNMP: Simple Network Management Protocol Saad Haj Bakry, PhD, CEng, FIEE Saad Haj Bakry, PhD, CEng, FIEE

Objectives / Contents SNMP Principles SNMP Information Representation SNMP: Simple Network Management Protocols Objectives / Contents SNMP Principles SNMP Information Representation SNMP Operation Remarks Saad Haj Bakry, PhD, CEng, FIEE

SNMP Principles Introduction Components Multi-Vendor Principles SNMP: Simple Network Management Protocols SNMP Principles Introduction Components Multi-Vendor Principles Information Flow Framework Saad Haj Bakry, PhD, CEng, FIEE

Introduction to SNMP For TCP/IP Networks: First issued in 1989 SNMP: Simple Network Management Protocols Introduction 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 (+) Saad Haj Bakry, PhD, CEng, FIEE

A Computer Running Management Software (with GUI) SNMP: Simple Network Management Protocols SNMP Components SNMP Management Station Router Agent Bridge Printer Host Managed Node Process LAN A Computer Running Management Software (with GUI) Managed Node Saad Haj Bakry, PhD, CEng, FIEE

SNMP Multi-Vendor Principles SNMP: Simple Network Management Protocols SNMP 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) Saad Haj Bakry, PhD, CEng, FIEE

Variables to describe devices SNMP: Simple Network Management Protocols SNMP Information Flow Managed Node Devices Device Agent Object Variables to describe devices MIB Data Structure Modules Using SMI (ASN-1) Rules to Describe Objects (Variables) Sequence of Bytes for Transmission Using BER Rules to Convert SMI Data Structures into a Sequence of Bytes SNMP Operations Saad Haj Bakry, PhD, CEng, FIEE

SNMP Framework Protocol: “Manager-Agent” interaction SNMP: Simple Network Management Protocols SNMP 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 Saad Haj Bakry, PhD, CEng, FIEE

SNMP Information Representation SNMP: Simple Network Management Protocols SNMP Information Representation SMI: Structure of Management Information MIB: Management Information Base BER: Basic Encoding Rules Saad Haj Bakry, PhD, CEng, FIEE

SMI Data Types (Examples) SNMP: Simple Network Management Protocols SMI Data Types (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 Saad Haj Bakry, PhD, CEng, FIEE

SMI: OBJECT IDENTIFIER (1/2) SNMP: Simple Network Management Protocols SMI: OBJECT IDENTIFIER (1/2) Top Level iso (1) ccitt (0) iso-ccitt (2) org (3) dod (6) Internet (1) Saad Haj Bakry, PhD, CEng, FIEE

SMI: OBJECT IDENTIFIER (2/2) SNMP: Simple Network Management Protocols SMI: OBJECT IDENTIFIER (2/2) 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} Saad Haj Bakry, PhD, CEng, FIEE

MIB: Definitions of Objects SNMP: Simple Network Management Protocols 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 are arranged in “groups” Some groups relate to “layer” of the protocol stack. Other groups relate to the system as a “whole” Saad Haj Bakry, PhD, CEng, FIEE

Simple Network Management Protocol SNMP: Simple Network Management Protocols SNMP MIB Architecture Simple Network Management Protocol SNMP MIB Application TCP / UDP ICMP IP ARP Data Link Physical Saad Haj Bakry, PhD, CEng, FIEE

Internet Protocols Application TCP / UDP ICMP IP ARP Data Link SNMP: Simple Network Management Protocols Internet 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 IP ARP Data Link Point-to-Point Control: LAN / WAN Physical Communication Interface: T-R / Links Saad Haj Bakry, PhD, CEng, FIEE

BER Structure Every value transmitted consists of up to 4 fields: SNMP: Simple Network Management Protocols BER 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 Saad Haj Bakry, PhD, CEng, FIEE

BER Structure: The Identifier SNMP: Simple Network Management Protocols BER Structure: The Identifier 2-bits 1-bit 5-bits Tag / Type 00 universal 01 application 10 context specific 11 private Data Type primitive 1 constructed Value Identification Number Saad Haj Bakry, PhD, CEng, FIEE

BER Structure: Examples SNMP: Simple Network Management Protocols BER Structure: Examples Integer: 49 00000010 00000001 00110001 Length Value Identifier String “xy” 00000011 00000010 01111000 01111001 79 (Hex) 78 (Hex) Saad Haj Bakry, PhD, CEng, FIEE

SNMP Operation Principles Manager-Agent Interaction Basic Messages SNMP: Simple Network Management Protocols SNMP Operation Principles Manager-Agent Interaction Basic Messages Saad Haj Bakry, PhD, CEng, FIEE

SNMP Operation Principles SNMP: Simple Network Management Protocols SNMP 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. Saad Haj Bakry, PhD, CEng, FIEE

SNMP Operation Request PDU Time Response PDU PDU: Protocol Data Unit SNMP: Simple Network Management Protocols SNMP Operation Management Station Request PDU Time Managed Node Agent Response PDU PDU: Protocol Data Unit Saad Haj Bakry, PhD, CEng, FIEE

Basic Messages (1/2) Requesting & Updating Variable Values SNMP: Simple Network Management Protocols Basic Messages (1/2) Requesting & Updating Variable Values 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 Saad Haj Bakry, PhD, CEng, FIEE

Basic Messages (2/2) Originator: Agent Receiver: Manager Response-PDU: SNMP: Simple Network Management Protocols Basic Messages (2/2) Originator: Agent Receiver: Manager Response-PDU: Response Message Trap-PDU: Trap Report Originator: Manager Receiver: Another Manager Inform-request Local MIB Description Saad Haj Bakry, PhD, CEng, FIEE

Remarks Future Work: SNMP Given Review: Practical Systems Using SNMP SNMP: Simple Network Management Protocols Remarks Future Work: Practical Systems Using SNMP Practical Work Follow Up SNMP Given Review: Principles Information Operation Saad Haj Bakry, PhD, CEng, FIEE

SNMP: Simple Network Management Protocols References 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. Saad Haj Bakry, PhD, CEng, FIEE