Chapter Four: Solving the Network Management Problem

Chapter Four:

Solving the Network Management Problem

Eleni Hailu

The solutions include:

• 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.

MPLSSP

Score

FR

Ethernet

ATM

FR

Ethernet

ATM

Cross ConnectionsTo SP Core

• 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.

Fault Management

Managed Network (Object

Model)

Configuration Management

Performance Management

Security Management

Accounting Management

Database(Schema)

SQL

Notifications, Responses

Sets, Gets

Database Access Layer

Database Access Layer

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 object-oriented 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 Directory-

enabled 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 LDAP-based directory system.