CT320: Network and System Administration

Fall 2018

SNMP

See this page as a slide show

CT320 SNMP

Slides adapted from www.jasonslater.co.uk

Introduction

What is SNMP ?

Definition

SNMP (Simple Network Management Protocol) is an industry standard communication protocol for managing and monitoring network devices. Its purpose is to provide a small, common and simple set of commands that allow network devices to be managed.

Why is SNMP needed?

What is SNMP technically?

Data Flow

Manager/Agent relationship

     NMS
     (Network Managemt Station)				 Managed System
    ┌─────────────┐                                     ┌─────────────┐
    │ Management  │-----------Commands-----------------▷│ Agent       │
    │ Process     │					│ Process     │
    ├ ─ ─ ─ ─ ─ ─ ┤◁----------Responses-----------------├ ─ ─ ─ ─ ─ ─ ┤
    │ Management  │					│ Management  │
    │ Information │					│ Information │
    │ Database    │◁----------Notifications-------------│ Database    │
    └─────────────┘                                     └─────────────┘

The MIB Namespace

                    root
           ┌──────────┼──────────────┐
           │          │              │
        itu-1 (0)   iso (1)       iso/itu-t (2)
                      │
           ┌──────────┼──────────────┬────────────┐
           │          │              │            │
    standard (0)   registration     member    Identified organization
                   authority (1)    body (2)   e.g. .com .org (3)
                                                  │
                                      dod (Department of Defense) (6)
                                                  │
                                              internet (1)
           ┌──────────┬────────┬────────┬─────────┴────┬────────────┐
           │          │        │        │              │            │
    directory (1)   mgmt (2) exp (3) private (4)  security (5)   snmpv2 (6)
                      │                 │
                   mib-2 (1)      enterprises (1)
                                        │
                 ┌───────────┬──────────┼──────────────┐
             cisco (9)    hp (11)   nec (119)     compaq (232)

Management Information Base

ftp://ftp.cisco.com/pub/mibs/v1/

nec              OBJECT IDENTIFIER ::= { enterprises 119 }
nec-mib          OBJECT IDENTIFIER ::= { nec 2 }
necProductDepend OBJECT IDENTIFIER ::= { nec-mib 3 }
atomis-mib       OBJECT IDENTIFIER ::= { necProductDepend 14 }
m5core-mib       OBJECT IDENTIFIER ::= { atomis-mib 3 }

node OBJECT IDENTIFIER ::= { m5core-mib 1 }
linf OBJECT IDENTIFIER ::= { m5core-mib 2 }
conn OBJECT IDENTIFIER ::= { m5core-mib 3 }
perf OBJECT IDENTIFIER ::= { m5core-mib 4 }

nodeFanStatus OBJECT-TYPE
SYNTAX INTEGER { up(1), down(2) }
ACCESS read-only
STATUS mandatory
DESCRIPTION "Operational FAN status"
::= { node 3 }

Example SNMP “GET” operation

  1. User makes request to NMS
  2. NMS initiates formal request
  3. Request traverses network
  4. Agent processes request
  5. Agent formulates reply
  6. NMS receives reply
  7. User informed of result

How is SNMP defined?

ASN.1

Abstract Syntax Notation One (ASN.1) is a formal language for abstractly describing messages to be exchanged among an extensive range of applications involving the Internet, intelligent network, cellular phones, ground-to-air communications, electronic commerce, secure electronic services, interactive television, intelligent transportation systems, Voice Over IP and others.

Due to its streamlined encoding rules, ASN.1 is also reliable and ideal for wireless broadband and other resource-constrained environments. Its extensibility facilitates communications between newer and older versions of applications. In a world of change, ASN.1 is core technology, constantly adapting to new technologies.

SNMP v1

SNMP v2

SNMP v3

Alternatives to SNMP

  • CMIP Common Management Information Protocol (ISO)
    • Variables can perform tasks as well as store information
    • Built-in security for authorisation, access control, and logging.
    • Wider set of commands
    • Handles unusual network conditions better
  • DME Distributed Management Environment (OSF)
    • Can integrate with SNMP (and CMIP)
    • Event Management
    • Print Servicing
    • Network licensing
    • Software Distribution
  • HNMS Hierarchical Network Management System (NAS)
    • Low management traffic
  • HMMA Hypermedia Management Architecture (WBEM)
    • Everything can be managed via a web browser
    • Lower costs — use of “already in place” web technologies

Summary

References

RFCs

  • RFC 1065 - Structure and identification of management information for TCP/IP-based internets
  • RFC 1066 - Management Information Base for network management of TCP/IP-based internets
  • RFC 1067 - A Simple Network Management Protocol
  • RFC 1089 - SNMP over Ethernet
  • RFC 1140 - IAB Official Protocol Standards
  • RFC 1147 - Tools for Monitoring and Debugging TCP/IP Internets and Interconnected Devices
  • RFC 1155 - Structure and Identification of Management Information for TCP/IP based internets.
  • RFC 1156 - Management Information Base Network Management of TCP/IP based internets
  • RFC 1157 - A Simple Network Management Protocol
  • RFC 1158 - Management Information Base Network Management of TCP/IP based internets: MIB-II
  • RFC 1161 - SNMP over OSI
  • RFC 1187 - Bulk Table Retrieval with the SNMP
  • RFC 1212 - Concise MIB Definitions
  • RFC 1213 - Management Information Base for Network Management of TCP/IP-based internets: MIB-II
  • RFC 1215 - A Convention for Defining Traps for use with the SNMP
  • RFC 1224 - Techniques for Managing Asynchronously-Generated Alerts
  • RFC 1270 - SNMP Communication Services
  • RFC 1303 - A Convention for Describing SNMP-based Agents
  • RFC 1470 - A Network Management Tool Catalog
  • RFC 1298 - SNMP over IPX (obsolete, see RFC 1420)
  • RFC 1418 - SNMP over OSI
  • RFC 1419 - SNMP over AppleTalk
  • RFC 1420 - SNMP over IPX (replaces RFC 1298)

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Modified: 2018-06-21T17:58

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