Transcript 5. A Real Network Management System

A Real NMS
Chapter 5
CIS 536 Network Management
By
Kode Venkateswara Rao
Hewlett – Packard’s OpenView
The following are the headings under which we
study the NMS:
a) FCAPS support – Basic NMS application
areas.
b) MIB support features.
c) MPLS Support.
d) Policy Support.
e) Reliability features, such as support for failure.
f) Integration with other software.
g) Programmability.
2
OpenView Network Node Manager
• Central to the function of NNM is the
management station. This is the computer that
performs the bulk of data collection like:
a) Collection of information from NEs via
SNMP.
b) Processing and archiving data in a
database.
c) Distribution to registered applications.
3
• There can be more than one management
station which can exchange information
with one another.
• Management station can delegate NE data
collection to collection stations.
• HP suggests that a single management
station can handle 5000 managed objects.
• Up to 60,000 objects can be managed if
collection stations are deployed.
4
NNM Features
•
•
•
•
•
•
Discovery and Mapping
Monitoring
Notification processing
Reporting
Data Warehousing
Backup and Restore of firmware and
configuration data
• Java interface for remote access to
management features
• Remote administration of NMS
5
Network Discovery and Mapping
• This NMS feature enables discovery of
new NEs.
• Automatic discovery frees the user from
potentially error prone task of manually
entering and maintaining the details of
deployed NEs.
• Large service providers deploy NMS from
the point in time that they start to build
their networks.
6
Discovery has three main stages. They are:
• Initial discovery of previously unknown NEs.
• Examples of Initial Discovery are
 IP address of SNMP agent on the device.
 Inventory details like cards deployed in the
device.
 Protocols, technologies running on the device
such as ATM, MPLS, X.25 and so on.
 Virtual connections, traffic profiles, route objects
and so on.
7
• Incremental discovery of changes that
occurred to previously discovered data.
• Discovery of removal – when a Network
Element is taken out of network, it is
automatically removed from NMS.
8
NNM Discovery and Mapping
• NNM provides and automatic discovery mechanism.
• Discovery process uses SNMP based polling and ICMP
requests to build a picture of the network.
• Discovery process populates an IP topology database
using a series of tables like Network-level connectivity,
Segments, Nodes, Interfaces.
• This grouping allows NNM to create logical maps of the
NEs and to graphically indicate operational status using
a color, such as green for up, red for down, etc.
• An icon representing a network can be expanded to
show the constituent nodes. In other words, containment
relationships are depicted clearly.
9
Monitoring
• This is a process of recording changes in
the status of managed objects such as:
Nodes
Interfaces
Links
Virtual Connections
Ethernet VLANs
10
• Status changes can have important bearing on
the service received by the end user.
• When an interface that is part of an ATM goes
down, the interface is no longer able to handle
the traffic. Such a status change may be service
affecting if there is no backup connection.
• Because of this Monitoring functions are an
important part of an NMS.
• The same process that carries out discovery
also executes NNM monitoring. Status changes
are reflected back into the topology.
11
Notification Processing
• An important part of fault management – this is
the (F) part of the FCAPS.
• Following would be the issues for SNMP
notifications.
 Notifications are not acknowledged by the NMS.
 Notifications are transported using UDP Protocol
and are unreliable.
 Faulty NEs can generate many notifications.
 Aggregated services which are faulty can
produce notification storms.
12
• When an NMS receives an SNMP trap over an
unreliable transport, it never acknowledges.
• This helps in scalability and keeps the
management protocol as lightweight as possible.
• It reduces network congestion.
• When an agent detects a problem, it sends a
best effort notification message and delegates
problem resolution to the NMS.
• Networks are designed to have at least 25%
bandwidth free to allow routing, signaling, and
management protocols to operate at all times.
• If this is followed then agent notifications should
always get through to the NMS.
13
NNM Notification Processing
• NNM uses the term EVENT to describe
NE notifications as well as messages from
other sources ( external applications).
• NNM provides an alarm browser for all
such events.
• Important events can then be configured
to show up as alarms for operator
intervention.
14
• NNM distinguishes between notifications and events.
Lifecycle for a notification is:
 An NE sends a notification.
 Notifications is received by NNM and logged.
 NNM distributes the notification to applications that are
registered for it.
• NNM allows notifications to be paired so that notification
A indicates a problem and notification B indicates
problem rectification. Such paired notifications assist a
network operator because they reflect those situations
when the network self heals.
• When the correction notification does not occur then the
fault remains active.
• NNM also supports event correlation in which a given
notification is processed before it is forwarded to one of
the applications.
15
Reporting
• Reporting is one of the most features of an NMS
in which data is retrieved from the network and
presented in a specified format.
• This can include the following:
 Deployed NEs
 NE configuration
 Interfaces
 Links
 Virtual Connections
16
NNM Reporting
• NNM reporting is GUI Based and is accessible
through a browser. The main options are:
 Report Configuration: Create, delete and modify
reports.
 Report Presentation: View reports.
• NNM reports can be:
 Scheduled
 Configured/viewed using a standard browser
 Automatically emailed to a recipient
17
• Examples of NNM pre-configured reports are as
following:
 Accounting
 Availability
 Congestion
 Historical Details
 Inventory
 Performance
 Real-time details
 Thresholds
 Trend Analysis
 Utilization
18
Data Warehousing
• NMS provides a persistent repository, that is, a
commercial database product such as Oracle.
• It is this database that is kept synchronized by the NMS
Application regarding the network state.
• It also facilitates data security by hosting the database in
a secure location with access grants only to authorized
clients.
• The user can view all the necessary information to
manage the network, such as, Viewing the configuration
of a given node, Provisioning an ATM virtual connection
between two nodes and so on.
• The database is therefore a key component of the NMS.
All the FCAPS applications use it.
19
Backup and Restore
• In network management both firmware and NE
configuration are high value items.
• The firmware version on a given NE is subject to change
as new features and technologies are added. It is
important to backup the existing version before any
upgrade.
• Once the NEs have been configured and are
operational, it is important to be able to backup the
settings, also called as configuration database.
• NNM provides a backup facility that allows a snapshot to
be taken of the topology and maps. These are frozen
during the time it takes to copy the data into a backup
directory. At no time during this process do the alarm
handling and data collection procedures stop.
20
Java interface for Remote Access
• Standard Java enabled Web browsers reduce
investment required for producing client side
NMS solutions because no development is
required for client application framework.
• Browser provides execution environment for
client applications.
• Use of java as number of merits:
 Java is object oriented.
 Provides built-in security
 Java is multiplatform programming language
 Java supports field-replaceable packages
21
NNM Java Interface
• Java based Web interface in NNM allows user to
connect to the NNM management station.
• It permits remote viewing of:
 Topology
 Alarms
 Node status
 MIBs
 Maps
 Graphs
• Java interface exports management station function onto
desktop systems equipped with standard browsers on
Remote clients.
22
MIB Support Features
• MIBs provide details concerning the
network managed objects and form the
basis for the NMS data model.
• NMS should provide number of baseline
features for MIB support like:
Load new MIBs
Support Multiple versions of the same MIB
Unload MIBs no longer in use
Browse and analyze MIBs
23
MPLS Support
• MPLS nodes have a number of managed objects, the
status of which can change over time:
 Interfaces can be up or down
 Routing protocols such as OSPF, IS-IS can be
operational or disabled.
 Forwarding table entries can be active or inactive
 LSPs can be up or down
• Other MPLS objects that do not change are:
 EROs
 Resource Blocks
 Cross-connects
24
• NNM provides no special support for
MPLS but can be extended to use the
appropriate MIBs.
25
Policy Support
• Network management terms and policies
can be used to automatically solve
recurring problems.
• One example is traffic thresholds. User
can set a threshold on an interface for the
number of packets received. If the
threshold is exceeded, a notification is
generated and the NMS can divert the
traffic.
26
NNM Policy Support
• Apart from basic policies like issuing emails in
response to certain events, NNM requires third
party products to implement policy handling.
• Policy based applications provide features such
as:
 Application prioritization
 Enterprise policy distribution, example: access to
NEs.
 User-based security policies and so on.
27
Reliability Features
• Backup facilities can help in improving reliability.
• In case of NMS, this can take the form of
protecting the central database with a failover
capability.
• User can deploy a backup version of the
database that runs in a parallel mode with the
primary system.
• NNM collection stations can be configured to
failover to remote management stations.
28
Integration with other software
• NMS can be integrated with some ancillary systems or
applications which can perform the following:
 Data export of network topology/inventory data for
business asset analysis
 Data export of software based modeling packages for
traffic analysis, network design. Specialized software
applications can be used to carry out offline traffic
analysis. A snapshot of the discovered topology can be
exported into a modeling package, and the user can
execute what-if scenarios. The effects of such changes
can be viewed offline before making the changes.
29
 Integration of alarms with trouble ticket system.
Alarms generated by the network can be routed
via the NMS to trouble ticket applications. This
allows for recording and directing any remedial
work required to clear the fault.
 Performance analysis regarding the number of
packets, cells, frames transported by a NE.
Many NEs generate performance data records
(PDR) that provide utilization details for:
a) Ports, links and virtual circuit utilization
b) Protocols
c) Networking technologies
30
Billing: Reports generation using CDRs
and other data such as connection type,
class of service.
Security – distribution of keys, user
accounts and passwords, digital
certificates and so on.
• NNM Integration:
 Many third party applications like
Microsoft System Management Server can
be integrated with NNM.
31
Programmability
• Facility of adding software to an NMS can
greatly extend its usefulness.
• Network management requirements are unique
to every network, so programmability is an
important addition.
NNM Programmability
• NNM allows for user-software to be added to
enhance the base functions.
• This can include reporting, alarm and event
processing.
32
Summary
• Effective network management requires broad
range of software tools.
• In NNM Network Management is achieved by
using a number of software packages.
• Special Software can be employed for billing,
mediation and performance analysis.
• Minimizing the gap between the network
situation and that perceived by the NMS is
crucial and provides a baseline for defining the
quality of a given NMS.
33