POSTECH DP&NM Lab
Overview of Network
Management
J. Won-Ki Hong
Dept. of Computer Science and Engineering
POSTECH
Email: jwkhong@postech.ac.kr
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POSTECH DP&NM Lab
Table of Contents
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Today’s Networks
Network Management Requirements
Network Management Systems
NMS Software Architecture
Distributed Network Management
Proxy Agent
Standard Management Frameworks
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Today’s Networks & Services
Local, Long-distance,
Oversea Phone service
080, 070, collect-call
third-party IN service
cellular, C2, PCS, TRS
World-Wide Web
Email, DNS, FTP
News, Telnet, IRC
RealAudio, RealVideo
MBone
Token
Ring
Fast
Ethernet
SDH
MPLS
ATM
SS#7
WANs
Gigabit
Ethernet
Computer Networks
Video Conferencing
Electronic Commerce
Internet Phone
Banking, Accounting
Distance Learning
Ethernet
B-ISDN
IN/AIN
Access
Networks
PCS
PSDN
PSTN
ISDN
Telecom Networks
Video-on-Demand
Tele-conferencing
Video-conferencing
Internet Telephony
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NM Users’ Requirements
• Controlling corporate strategic assets
– effective control of network & computing resources
• Controlling complexity
– continued growth of devices, users, applications & protocols
• Improving service
– users expect better service with increased resources
• Balancing various needs
– must assign and control resources to balance various needs
• Reducing downtime
– more users and applications depend on availability
• Controlling costs
– effective resource utilization in order to control costs
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NM Functional Requirements
• Fault Management
– detection, isolation and correction of abnormal operations
• Configuration Management
– identify managed resources and their connectivity, discovery
• Accounting Management
– keep track of usage for charging
• Performance Management
– monitor and evaluate the behavior of managed resources
• Security Management
– allow only authorized access and control
FCAPS
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Fault Management
• concerned with:
– providing a reliable networking environment
– ensuring that the systems as a whole, and each essential component
individually, are in proper working order
– redundant components and routes can be used to increase fault
tolerance
• when a fault occurs, the manager should be able to:
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determine exactly where the fault (i.e., abnormal condition) is
isolate the rest of the network from failure
reconfigure or modify the network for continued operation
repair or replace the failed components to restore the network
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Configuration Management
• concerned with:
– initializing a network & shutting down part or all of the network
– maintaining, adding and updating the relationships among
components
– monitoring the status of components during network operation
• the network manager should be able to:
– startup and shutdown operations on a network
– identify the components that comprise the network (discovery)
– change the connectivity of the components (possibly as a result of
network upgrade, fault recovery or security checks)
– detect changes in the network configuration
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Accounting Management
• concerned with:
– keeping track of the usage of network resources
– charging the use of network resources
– monitoring the end-user activities for possible abuse, for suggesting
better usage to users and for network planning
• the manager should be able to:
– specify the kinds of accounting information to be recorded at various
nodes
– specify the algorithms to be used in calculating the charging
– generate accounting reports
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Performance Management
• concerned with:
– providing an efficient communication environment
– monitoring and analyzing the performance of the components
– making proper adjustments to improve network performance
• the manager should be able to:
– determine the capacity utilization, throughput, the average and worstcase response times
– monitor and gather data on the activities of components
– analyze the gathered data and assess performance levels
– determine the sources of performance problems & fix them
– use the performance stats for future network planning
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Security Management
• concerned with:
– providing a secure networking environment
– preventing hacking, illegal and unauthorized access
– managing information protection and access-control facilities
• the manager should be able to:
– generate, distribute and store encryption keys
– maintain and distribute passwords and other authorization or accesscontrol information
– monitor and control access to networks
– collect, store and examine audit records and security logs
– enable & disable the logging facilities
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Network Management Systems
• A network management system (NMS) is a collection of
tools for network monitoring and control
• based on the manager-agent paradigm
– the manager sends mgmt requests to one or more agents
– an agent performs the requested operation and returns results
– when agents detect faults and they report to the manager
• NMS typically provides a GUI through which most or all
management tasks can be performed
• Many commercial and freely available NMSs exist:
– HP OpenView, IBM NetView, Sun Net Manager, etc.
– research prototypes from CMU, MIT, UC Davis, U. of Twente
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Management Platform
Collect, organize & interpret
Operational Data
Administrator
Workstation
mgmt requests/replies
event reports
Agent
Agent
Agent
Agent
Agent
Agent
Agent
Observation
& Control
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Elements of an NMS
Server
(agent)
Network control
host (manager)
NMA
NME
NME
Appl
Appl
Comm
Comm
OS
OS
Router
(agent)
Workstation
(agent)
Networks
NME
Comm
NME
Appl
OS
Comm
OS
NMA = network management application
NME = network management entity
Appl = application
Comm = communications software
OS
= operating system
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Network Management Entity (NME)
• NME is a collection of software devoted to the network
management tasks
• is typically known as an “management agent”
• Each NME performs the following tasks
– collects statistics on communications and network-related activities
– stores statistics locally
– responds to commands from the network manager, including
commands to:
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transmit collected stats to network manager
change an attribute value
provide status information
generate artificial traffic to perform a test
etc.
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Network Mgmt Application (NMA)
• NMA is a collection of software for performing network
monitoring and control
• is typically known as “network manager”
• NMA provides an operator interface to allow an authorized
user to manage the network
• NMA responds to user commands by displaying information
and/or issuing commands to NMEs
• Standard protocols (e.g., SNMP, CMIP) are used to manage
a multi-vendor network
• there may be more than one NMA in a large network which
can lead to the need of a hierarchy of managers (e.g., top
level manager, middle level managers, etc.)
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NM Software Architecture
• User Presentation Software
– interfaces between user and NM software
– a unified user interface desirable
– includes graphical tools to display summarized NM information
• Network Management Software
– a set of NM applications (configuration, performance, etc.)
– a set of application elements (alarm handling, logging, etc.)
– NM data transport service
• Communication and Database Support Software
– local Management Information Base (MIB) access module
– communications protocol stack (e.g., TCP/IP, OSI) to interact with
remote agents and managers
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Architectural Model of NMS
Unified user interface
Presentation of network management information to users
Network management
application
application element
Network management
application
...
application element
...
application element
Network management data transport service
MIB access
module
Management
Information
Base
Communication
protocol stack
Managed networks
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Distributed Network Management
• Resources to be managed are widely distributed
– widespread use of departmental LANs
– need for local control & optimization of distributed applications
• Hierarchical NM architecture desirable
– distributed NMSs are given limited access for network monitoring and
control of departmental resources
– top-level NMS has a global access rights and the ability to manage all
network resources
• Benefits of Distributed NM
– NM traffic overhead is minimized - traffic is localized
– Dist. mgmt offers greater scalability
– use of multiple NMSs eliminates the single point of failure
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Typical Dist. Mgmt System Architecture
Management clients (PCs, workstations)
Network
Management server
Management
application
Management server
Management
application
MIB
MIB
Network
Element
manager
Element
manager
Network resources (servers, routers, hosts) with management agents
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Proxy Agents
• Managed resources may have various mgmt interfaces
– some with different mgmt protocols (e.g., OSI vs. SNMP, XML vs.
SNMP)
– some with proprietary mgmt interfaces (e.g., older systems)
– small systems not capable of possessing NME (e.g., modems)
• Proxy agents are used to manage these devices
– managers use standard protocols to communicate with proxies
– proxy agents use proprietary protocols to communicate with
proprietary devices
– proxy agents perform translations between managers and proprietary
devices
– an agent to the manager and a manager to proprietary devices
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Proxy Agent Architecture
Management
application
Proprietary management
interface
Proxy Agent
Client
stub
Server stub
Client proxy
stub
Server proxy
stub
Protocol
stack
Protocol
stack
Protocol
stack
Protocol stack
Standard operations
and event reports
Proprietary operations
and event reports
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Standard Management Frameworks
• Internet Network Management Framework (IETF)
– SNMPv1 (Internet Full Standard)
– SNMPv2 (Internet Full Standard)
– SNMPv3 (Internet Proposed Standard)
• OSI Network Management Framework (ISO/ITU-T)
– CMIP (X.700 Series)
• Telecommunication Management Network (ITU-T)
– TMN (M.3000 Series)
• Web-based Enterprise Management (DMTF)
– CIM, XML, Web Services
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Summary
• Network Management Requirements
– Users’ Requirements
– Functional Requirements (FCAPS)
• Network Management Systems
– Network Management Entity (NME)
– Network Management Application (NMA)
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NMS Software Architecture
Distributed Network Management
Proxy Agent
Standard Management Frameworks
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Useful Internet Resources
• Web Sites
– http://snmp.cs.utwente.nl/ (SNMP, NM RFCs)
– http://www.itu.int/ITU-T/studygroups/com04/ngn-mfg/index.html
(NGN Management Focus Group)
– http://www.tmforum.org/ (TM Forum)
– http://www.ietf.org/html.charters/wg-dir.html (IETF)
– http://www.dmtf.org (DMTF)
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Questions?
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