Lecture09f - Prof. Shervin Shirmohammadi CEG 4395 9-1...

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Unformatted text preview: Prof. Shervin Shirmohammadi CEG 4395 9-1 Lecture 9: SNMP Communication and Functional Models Prof. Shervin Shirmohammadi SITE, University of Ottawa Prof. Shervin Shirmohammadi CEG 4395 9-2 Overview •We have covered the organization and information models of SNMPv1. •Here we will address the SNMPv1 communication and functional models •SNMPv1 does not formally define a functional model –What was the functional model? •Deals with the user oriented requirements: (configuration, fault, performance, security, and accounting) –The functions are actually built in the community- based access policy of the SNMP administrative model. Prof. Shervin Shirmohammadi CEG 4395 9-3 SNMP Manager Application G e t-R e s p o n s e G e t-R e q u e s t G e tN e x t-R e q u e s t S e t-R e q u e s t T r a p SNMP Manager SNMP UDP IP DLC PHY SNMP Agent Application G e t-R e s p o n s e T r a p SNMP Agent SNMP UDP IP DLC PHY Physical Medium Figure 4.9 SNMP Network Management Architecture Manage- ment Data G e t-R e q u e s t G e tN e x t-R e q u e s t S e t-R e q u e s t SNMP Architecture Prof. Shervin Shirmohammadi CEG 4395 9-4 SNMP Messages •Get-Request •Get-Next-Request •Set-Request •Get-Response •Trap –Generic trap –Specific trap –Time stamp •UDP is unreliable, so what happens if these messages are lost? Prof. Shervin Shirmohammadi CEG 4395 9-5 SNMP Trap Messages •Generic trap –coldStart –warmStart –linkDown –linkUp –authenticationfailure –egpNeighborLoss –enterpriseSpecific •Specific trap –for special measurements such as statistics •Time stamp : Time since last initialization Prof. Shervin Shirmohammadi CEG 4395 9-6 Administrative Model •Based on community profile and policy •SNMP Entities: –SNMP application entities-Reside in management stations and network elements-Example SNMP Manager and SNMP Agent –The Pairing of these 2 names is known as a community –SNMP protocol entities-Communication processes (PDU handlers)-Peer processes that support application entities Prof. Shervin Shirmohammadi CEG 4395 9-7 SNMP Community •Security in SNMPv1 is community-based –Not very secure, as we shall see •Authentication scheme in manager and agent •Community : Pairing of two application entities –Community name : String of octets •Two applications in the same community communicate with each other –A local concept: local to the managed station •Application could have multiple community names •Communication is not secured in SNMPv1 – no encryption Prof. Shervin Shirmohammadi CEG 4395 9-8 SNMP Manager Authentication Scheme SNMP Manager Authentication Scheme SNMP Manager Authentication Scheme SNMP Agent Authentication Scheme Authentic Messages Figure 5.1 SNMP Community SNMP Community Managed station might give different access rights and views to different managers Prof. Shervin Shirmohammadi CEG 4395 9-9 Community Profile •MIB view –An agent is programmed to view only a subset of managed objects of a...
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This note was uploaded on 02/15/2009 for the course CEG CEG4395 taught by Professor Ahmadeid during the Spring '09 term at Punjab Engineering College.

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Lecture09f - Prof. Shervin Shirmohammadi CEG 4395 9-1...

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