Transcript 4. Network Management Problem

Chapter Four:
Solving the Network
Management Problem
Eleni Hailu
The solutions include:
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Filing the Development skills gap
Smarter NMs
Smarter MIBs
Smarter NEs
One data Model
Distributed Server
Policy-based Network Management
Directory Enabled Networking
Filing the development Skills gap
• Managing any given technology resolves
down to the associated managed objects and
management software.
• In Solution Engineering, the overall focus is not
on a single item of work rather a combination of
all the following components:
• A complete GUI feature consisting of one or
more screen pages
• The provisioning code for a feature such as
IP traffic engineering
• A topology backend combined with fault
management
• Performance monitoring software
Filling…
• Adding special-purpose NMs software
infrastructure is particularly useful when software
problems occur on used sites.
• The user can generate trace files and email
them back to the developers for analysis and
the developers can dial into the site and
generate the trace files themselves.
• This helps avoid the need for developers to
travel and can result in fast problem
identification and accurate resolution.
Filing…
• There are many ways of adopting a
solution engineering such as
• Web Browsing
• Virus Detection
• Document Processing
• Software Development
Filing….
• Identifying and learning the constituent
components usefully leverage the intellectual
property freely available with GUI-based
applications. This is beneficial because many of
the components have become standard desktop
objects such as:
• Pull-down menus
• Dialog boxes
• Toolbars
• Icons
• Task bars
Components
• An important aspect of components is that
they should model real-world objects as
closely as possible, including relationships
to other objects.
• The components should be easy to
combine, provision and monitor so that the
appropriate relationships are maintained
between the two enterprise sites.
Components….
• NMS also have other components that add value
by being as loosely coupled as possible, such
as:
• Scheduling facilities
• Virtual connection creation, modification,
and deletion facilities
• NE firmware backup and restore features
• NE configuration database backup and
restore, including network inventory details
like port configuration settings, IP
addresses, protocol settings, and virtual
connections.
Cross-functional Cooperation
• The complexity of NMs software development is
such that many different people are generally
involved in its production, including:
• Sales and marketing executives
• Specifications and release planning experts
• Designers and domain experts
• Developers
• QA/Test personnel
• IT Managers
• End Users
Cross-functional …
• Quality Assurance (QA) can also assist in the
early stages of development by first testing
paper models and later testing stubbed software
builds. These builds provide the skeleton of the
end system with much of the function not yet
implemented.
• The setup and maintenance of modern NEs
increasingly require professional system
administration skills. The contribution that IT
can make to this is significant, particularly when
many users are sharing the NEs.
Cross-functional…
• Ownership and moving around the
development environment need to be
balanced against the needs of the
developers. These are include:
• GUI
• Backend
• Middleware
• Database
• Deployment facilities for software
installation and upgrade
Software Deployment
• Deployment software is the first thing the end users
sees during installation of a give NMS. The following
are guidelines for successful deployment:
• Ease of use – the NMs Should install/upgrade
easily.
• Speed – deployment should be fast, minimizing
downtime.
• Function – deployment should, if possible, not
require any downtime as new code is applied.
• Auditable – it should be possible to verify that new
code has been successfully (or unsuccessfully)
deployed.
• Ease of removal – the NMs should uninstall
cleanly and efficiently.’
Smarter NMs
• NMs (Network Management System) is
a term that describes a computer based
software application suite dedicated to
the management of networks of
network elements.
Smarter NMs….
• NMs must increasingly support high level
of:
• Reliability
• Availability
• Maintainability
• Preprocessing NE requests in order to
reduce the number of messages sent to the
network
• Discovering static NE data
• Minimizing the amount of data retrieved
from NEs.
Adding Service Management
• The NMs offers a high-level service
management capability over a MPLS backbone ,
because NMs deals interms of services rather
than just connections and devices.
• Service management can be made up of more
than one connection and requires a new type of
managed object for:
• Visual representation
• Provisioning
• Monitoring
• Auto-learning
MPLS SP Score
• An interesting aspect of MPLS is that
it will allow enterprise network cores to
become more generic. Regardless of traffic
type, it will be transported over LSPs/tunnels.
Cross Connections
To SP Core
FR
Ethernet
ATM
FR
MPLS
SP
Score
Ethernet
ATM
• NEs must provide:
• Unified signaling across multiple domains
• Srevice level traps.
• Implementing services is difficult in a
network comprised of several different
domains, such as ATM, IP, MPLS, Frame
Relay and X.25.
NMs Structure
• Most NMs are vertical applications and
Stovepipe fashion is implemented and
data flows up and down.
• There is little horizontal communication
between the stovepipes because they are
both database and NE-centric and fulfill
specific FCAPs (fault, configuration,
accounting, performance and security)
function.
FCAPS STRUCTURE
• FCAPS function are the OSI functional areas of
network management.The following figure
illustrates the baseline FCAPs structure.
Database
(Schema)
SQL
Database Access Layer
Fault
Management
Configuration
Management
Accounting
Management
Performance
Management
Database Access Layer
Notifications, Responses
Sets, Gets
Managed
Network (Object
Model)
Security
Management
NMs….
• NMs needs additional software such as:
• Toplogy management
• NE firmware backup and restore
• NE configuration and database backup and
restore.
• Topology components may contain
subordinate objects, such as
• Nodes contain interfaces
• Interfaces carry virtual connections
• Links join together adjacent interfaces
Smarter MIBs (Management
Information Base)
• MIBs represent a shared name space
between SNMP agents and Managers.
• They allow an operator to leverage the
management facilities deployed in the
network.
• MIB notes are primarily intended to
promote NE manageability.
NE Manageability
• High levels of NE manageability offer a
number of benefits:
• The NE is easier and cheaper to
incorporate into a network and an NMs.
• The specific NE features are easier to
access and manage.
• End-user confidence levels are raised with
regard to the vendor.
• The NE acquires a degree of product
differentiation.
MIBs…
• Some aspects of MIBs that improve
manageability are:
• MIB Note: Avoid MIB object semantic
dependencies
• MIB Note: Provide default MIB object
values
• MIB Note: Centralize MIBs to match NE
features.
MIB table column:
• Semantic dependencies complicate
provisioning code because the NMs
software has to understand the columnar
relationships. In addition, they also
complicate the database schema when the
columnar relationships have to be
duplicated.
• Default values can be given to extraneous
MIB objects. This object is used when
creating a tunnel in which the user wants to
constrain the signaling path through an
MPLs cloud so that it uses only a specific
type of interface on each hop.
MIB table….
• This is similar to solution engineering
considerations MIBs should be structured
so that solution components are clearly
expressed and easily accessed.
• MIB Notes provide good reason for the
developers of NMs maintaining the MIBs
to work in close cooperation with the NE
developers.
One Data Model
• The data stored and maintained in the managed
network must, at some point, be imported into the
NMS and stored in some type of persistent
repository.
• Repository data is manipulated by the NMs and for
actions such as provisioning, is written to the
network as MIB object instance values.
• The data model is the glue for bringing together the
managed NE Data and the user’s view of the
network.
• Maintaining parity between NMs and its
managed network is fundamentally limited by:
• Network size and bandwidth
• NE density – the number of managed
objects
• NE agent resources
• The NMs must try to maintain data parity and, at
the same time, minimize NE access.
Distributed Server and Client
• NMs are increasingly large, complex
application suites. Rather than using a
single server with multiple distributed client,
more than one server machine can be used
and it helps to distribute the processing
among a number of host machines.
• NMs can also be operated in redundant
mode. This constitute of deploying a
primary server with one or more backup
server.
Deploying Primary Server…
• Allows for the Entire NMS to be backed up
in a number of configurations:
• Hot standby: the secondary takes over
with no data loss.
• Warm Standby: The secondary takes over
with some data loss.
• Cold Standby: The secondary is started up
and switched into services.
Smarter NEs
• The NEs:
• Follow the installed policy guidelines
• Watch for the indicated conditions.
• Execute the required actions.
• Policies are a little like SNMP notifications in that
the NE performs work independently of the NMs.
• The need for advanced, real-time services, such
as voice and video-over–IP, on enterprise and SP
networks is also resulting in a need for greater
NE intelligence.
Policy-Based Network
Management (PBNM)
• PBNM is one of the most important
direction being taken in network
management. It recognizes that trying to
manage individual devices and
connections using a simple
get/set/notification mode is no longer
sufficient because of the demands
increasingly being placed on networks.
PBNM
• PBNM introduces a number of new and
interesting entities into network
management. PBNM architectural
elements are :
• Policy Console
• Policy Repository
• Policy server/decision point (PDP)
• Policy Enforcement Point (PEP)
Network Management Policies
• Network management policies can be
simple resource allocation such as:
• Give traffic from IP address a. b.c.d. the
highest priority forwarding treatment.
• Assign email traffic the lowest priority
forwarding treatment.
• Assign VoIP traffic assured forwarding
treatment.
Network Management…
• Other network management policies can
be in the form of NE configuration
information such as:
• Protocols
• Interfaces
• Network-wide settings.
Directory-Enabled Networking
(DEN)
• DEN is the way in which the managed
objects, such as nodes, interfaces, links,
virtual connections, network clouds, routes
and resource blocks are represented
inside the NMs.
• The purpose of DEN is to bind users and
services to NEs, Network paths,
bandwidth and other network parameters.
DEN
• DEN is a specification of an objectoriented information model, such as:
• Classes, such as generic nodes
• Class attributes, such as location,
owner/operator
• Class methods, such as delete a specified
node for notification
• Class relationships, such as a node that
owns connections that originate on it and
terminate on other nodes.
DEN
• The focus on DEN lies in providing a type
of single system by combining:
• A technology-independent information
model.
• A directory system for storing policies, the
object model and the network devices.
• A policy system as discussed earlier
• A traditional SNMP based NMs.
Information Model…
• There are 2 important standard
information model:
• The common Information Model (CIM)
• An Extension to CIM called Directoryenabled networking (DEN)
• CIM is an object-oriented model that
describes how a system and its
components may be managed.
Information model….
• CIM model components are:
• System
• Devices
• Application
• Network
• DEN is an extension of CIM. DEN
provides a mapping of the information to a
format that can be stored in an LDAPbased directory system.