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NM architectures & RMON
OSI Network Management Architecture
OSI NM Model
Network
Management
Organization
Model
Information
Model
Communication
Model
Functional
Model
OSI Organization Model
Domain concept
The Management system is a domain
Has Manager system and Managed system
A managed system has
Managed Objects
A Managed Object can have
A number of other managed objects
OSI NM model
Informational Model - MIB
Communication Model - messages
Functional Model – five basic functions
Architecture of the OSI NM model
System Management Application Process
System Management Interface
LME
Management
Information
Base
(MIB)
CMIP
SMA Entity
LME
Presentation Layer
LME
Session Layer
LME
Transport Layer
LME
Network Layer
LME
Link Layer
LME
Layer Management Interface
Physical Layer
LME – LM entity
CMIP Common Management Information Protocol
Telecommunication Management Network
It is network – an overlay network, which
can be used for managing telecom and
datacom networks
Comprises of Operations Support Systems
Eg traffic measurement system
Trunk test System
Network Management System
IEEE NM architecture
IEEE primarily a workgroup working on
LANs
IEEE 802.1B LAN/MAN standards – LMM
Uses CMIP - Common Management
Information Protocol
Contd..
LAN/MAN management service (LMMS)
service available to the user (LMMU)
LAN/MAN management protocol entity
(LMMPE)
communicates management information via protocol
exchanges
Convergence Protocol Entity (CPE)
Enables LAN MAN environment to provide LMMS
adds functions of reliable and sequential data delivery
(LLC provides unacknowledged connectionless service )
Contd..
LMMU
Lan/Man
Management
Protocol
LMMPE
CPE
LMMU
LMMPE
Convergence
Protocol
CPE
LLC
protocol
LLC
LLC
Internet NM
Three proposals
High Level Management System
OSI based CMIS and CMIP – long term
Extending the SGMP – simple gateway
monitoring protocol – SNMP – Simple
Network Management Protocol – short term?!
SNMP architecture
Management System
Management
Application
SNMP
Manager
UDP
Managed System
Application
Manages Objects
SNMP Messages
Managed
Objects
SNMP Agent
UDP
IP
IP
Link
Link
Network
Get, Get-Next, Set, Get-Response, Event
SNMP
Manager / Agent Model
SNMP is simple
Agent requires minimal software
Most of the processing power at the Manager
Limited set of management commands
No pre-arranged path – connection set-up
SNMP is robust
Manager , Agent protocols can run
independently
Using CMIP
Management System
Managed System
Management
Application
Managed
Objects
Application
Manages Objects
CMISE
ROSE
CMISE
ACSE
CMIP Messages
ROSE
LPP
UDP
ACSE
LPP
TCP
UDP
IP
Link
TCP
IP
Link
Network
CMIP
Architecturally fits the Manager /Agent
model
Reliable transport
Application layer connections
Uses 3 OSI services
Common Management Information Services
Element (CMISE)
Remote Operations Service Element (ROSE)
Association Control Service Element (ACSE)
Association Control Service Element
Helps establish and release associations
between application entities
Has to be done before any management
operations can be performed
Can be initiated either by the manager or by the
agent
Allows Manager and Agent to exchange and
establish
‘Application context’
Remote Operations Service Element
similar to Remote Procedure Call
allows invocation of an operation to be
performed on a remote system
helps correlate requests and responses
exchange of parameters
transaction oriented service
Common Management Information Service
Element
Provides basic management services
Uses both ROSE and ACSE
Provides confirmed and unconfirmed services
Reporting events
Retrieving management data
Manipulating management data
Architectural categories
Hieratical Network Management
Distributed Network management
Centralised Network Management
Centralized
Network Control Host performs management
Uses a single database – back up needed
Could have a stand-by
Good for main-frame vendors
Good for Information system executives
Manager has control over the entire network
Easy to balance resources
Optimise overall utilisation
Easy troubleshooting
Convenience, accessibility and security
Contd..
Can allow access to other consoles
Can forward events to other consoles
Not scalable
Querying all devices from a single point –
traffic - throughput
Eg: IBM’s Netview – for SNA
Hierarchical
Multiple systems
One system is the central server
Others are clients
Clients can be configured to monitor and
poll different portions of the network
Client/server database technology
Central database with backup
Contd..
Distribution of network management tasks
Not dependent on a single system
Centralised storage
Saves valuable bandwidth resources
Clients close to the monitoring system – quick
pick up of information
Gathering information may be difficult
Overlap of devices across clients should be
avoided
Eg: Sun Net manager, HP Openview
Distributed
Combines centralised and hierarchical
Multiple peer platforms
One platform is the leader
Individual platforms can have a complete
database
Each peer system performs various tasks
and reports result to the central system
Features
Single location for all information
Single location for access to all
management applications
Not dependent on a single system
Distributed network management tasks
Distributed network monitoring
Problem:
Database replication
New NM ventures
Distributed Management Task Force
www.dmtf.org
Common Information Model
Web based Enterprise Management
Java Management APIs - JMAPI
Remote Monitoring (RMON)
Monitoring or Probing a Network
Monitored and analyzed information is sent
to a remote Network Management Station
The Network Management Station is
remotely managing the network via the
probe .
FDDI Probe
Remote FDDI LAN
Router with
RMON
Bridge
FDDI Backbone
Router
Local LAN
Router
NMS
Remote Token
Ring LAN
Token Ring
Probe
Ethernet
Probe
All four probe devices above are RMON
devices
The RMON device monitors the local
network segment and does necessary
analyses
Relays solicited and unsolicited
information to the NMS
Local polling of information and
inform NMS on alarm
Advantages
Reduces SNMP traffic
Loss of long distance pinging packets
reduced
More frequent polling
Quicker fault diagnosis and report to NMS