Jose Marcos Nogueira and Antonio A.F. Loureiro (jmarcos, loureiro)@dcc.ufmg.br

Department of Computer Science Federal University of Minas Gerais

Belo Horizonte, MG, Brazil

Abstract A telecommunications network can be roughly seen as a set of switches (exchanges), interconnected by a

set of transmission systems. There is also an access network that connects the user equipment to one of the system's switches. Through the access network, users gain access to the rest of the telecommunications network. Usually, the equipment and systems used on a telecommunications plant differ from each other with respect to functionality, architecture, and implementation technology.

The high degree of distribution makes it impossible to have all the network resources attended by human operators. Funhennore, a significant portion of the equipment is installed on remote locations (e.g., radio stations on top of mountains) and needs to be remotely monitored and controlled.

As a consequence of heterogeneity, there is a trend towards the installation of a new monitoring and control system for each new equipment deployed in the telecommunications plant. Generally, those monitoring and control systems are specially designed for a specific application and do not cooperate very much among themselves. Therefore, the management of those huge, heterogeneous and highly distributed networks is a very complex task due to their low degree of integration.

This typical scenario of a telecommunications network is exactly the scenario where Telemar, the largest telecommunications company of Brazil, operates. The plant is composed of a large variety of switching equipments and ttansmission systems, differing not only by their vendors but also by their technology, age and way of monitoring and control.

In order to solve that management problem, a distributed management platform called SIS (System for Integration of the Supervision) was developed. This platform is fully operational and implemented in a real telecomniunications plant. SIS has been evolving since mid 1990s. when it was initially deployed. The platform was conceived to allow the management of new systems and showed to he a key factor for the company as its business focus also evolves (e.g., the management of data communication networks of other companies such as bank, airline company, and large retailer).

In this paper, we discuss the development and use of the SIS platform, its design and main modules.

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SI§ Management Model

SIS Platform Plant

In 1990, ii distributed network management platform started to be conceived by Federal University of Minas Gerais (UFMG) jointly, and funded by Telemig, which was the regional telecommunications company of Minas Gerais (a state with the second economy in Brazil and an area almost as large as France). At the time of the deregulation process in Brazil, Telemig and other regional companies had telecommunications plants composed of a large variety of switching equip.ments and transmission systems, differing not only by their vendors but also by their technology, age and way of monitoring and control, which started to be incorporated into their plants since mid 1970’s. This platfom? is called SIS (System for Integration of the Supervision) [ I ] and covers all five functional management areas (fault, configuration, performance, security, and accounting). The SIS platform was successfully deployed in Telemig’s plant and become a key aspect for the company that started to offer new and better services to its customers. In fact, Telebras, a big state holding, ranked Telemig one of the top regional telecommunications company for almost IO years before the privatization process.

In 1998, a new privite company called Telemar incorporated Telemig and other 15 regional companies, creating the largest Brazilian telecommunications company. Currently, Telemar has approximately 15 and 2.2 million fixed and mobile customers, respectively. Telemar operates in an area over 60% of the Brazilian territory, which corresponds to 53% of the U.S. territory.

Given this unique scenario, as described above, Telemar made a strategic decision and decided to use the SIS network management platform to manage its entire fixed telecommunications plant. In this paper, we discuss the development and use of the SIS platform in a real telecommunications plant.

In the SIS, a plant to be managed - composed of equipments, systems, and telecommunication networks, all of which called supervised Entities - is seen as an hierarchical organization that has geographic administrative regions. A supervised entity belongs to a sub-region that in turn belongs to a region. The regions, when combined, constitute an area or core. The set of geographical areas form the total area to be managed. There are other relationships among supervised entities and system entities. For instance, building stations belong to sub-regions and they have supervised entities. Building stations are also associated with management centers, where operators are located.

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SIS Architecture: functional e:* Organized into functional

General '4- modules

9 Hierarchical relationship ~~~ ~ .....

UCRJ L&J Rcslonvlcv - Higher level: entire plant can . . .... ~~~~~ ~.~ be~seen, managed, and 'A ;A

operated 3 Sukeplonvlew

Managed neworb, - Lower level: only a region of

the plant can be supervised

9 System is physically realized netuakelemml

through a set of interconnected networks Mal" centra, U",, *d.o*bn

:& PIaglonal c o r n , ""8,

id S"brsg,onlUCsrn, U""

WE. N.lxa*Elamcn

The main goal of a network management system, when viewed in a broader context, is to help both the technical operation of the plant and the business needs. Thus, a network management system, systems management applications, inventory and other related applications must share and exchange information among themselves in order to have an integrated solution. The SIS distributed management platform provides the integration of a large number of heterogeneous systems and equipment. The networks and network elements are managed by protocols and systems that are not always standardized or compatible among themselves. In this scenario, it is important to have a common operation environment for telecommunication providers, such as the one provided by the SIS platform. In particular, when the human operator is involved in the management process, a common operation environment is fundamental, since there is no need to make operators proficient with specialized platforms and systems.

The SIS functional architecture is organized into functional modules which have a hierarchical relationship. ' In the higher level the whole plant can be seen, managed and operated. In the lower level only a region of the plant can be supervised. The modules, although very similar in function, play different roles depending where they are in the hierarchy.

Each module is called central unit and its function varies depending on the the level it is located. However, the software code of each module is almost the same.

The system is physically realized through a set of interconnected LANs. In each LAN, which corresponds to an operation center, it is possible to have several modules, processes, interfaces, and applications running. The interprocess communication is mainly implemented using the Remote Procedure Call (RPC) paradigm. The separation between the functional and physical architectures allows the establishment of very robust systems, i.e. a physical realization can be made in order to present all the good proprieties that lead to very reliable operations.

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SIS Architecture: software families

0 Four different software families: - Access to network

- Interface to operators - Interface to DBMS - Management and

applications

elements

NE

The SIS platform has four different software families: access to the network elements, inlerface to human operators, interface to DBMS, and management and applications. All modules and applications interact with a distributed DBMS using generic interfaces which makes the system independent of database vendors.

The above figure shows the main software modules of a central unit. The module Ucproc is responsible for control the whole system. Manager and MonitorSSS are interfaces between the rest of SIS and the managed networks (network elements and supervisory systems). InterfaceBD is a generic interface to data base management systems.

Sisterm (and Artemis) are the operational interfaces (GUI). One interface to human operators which is realized through a SIS module called SISTerm. This is a graphical interface that provides all functionalities needed by a SIS operator. In general, a SISTerm is initiated in a workstation running Solaris, Linux or Windows and its associated window manger

Currently the system is completely deployed over a wide territorial area in a plant comprised of different network elements. The SIS can collect, store, and process a broad range of data originated from thousands of supervised elements. Furthermore, it can execute telecommands over hundreds of network elements.

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SIS Architecture: NE communication 0 The communication interface

between SIS and network elements is organized in layers: - communication support layer - application layer

0 The management services provided by the SIS architecture defines CMIS-like services

0 The rnanaaement architecture defines twi classes of objects: - alarmRecord - Action

f The AgenVManager interface relies on the distributed client- server paradigm

for the SIS platform a:* Several agents were implemented

SIS Lab UFMG Brazil

The communication interface between SIS and network elements is organized in layers. The communication support layer transports messages between application entities. It is implemented by the TCPiIP stack over serial lines or network interfaces. The application layer controls the interaction between managers and agents. This layer has functions that resides at the session and presentation layer of OS1 model.

The management of a telecommunications plant is achieved through specific functions of the application layer: the MIS-User. The MIS-User is an application entity which implements management functions. It can act in two roles: agent and manager. When the MIS-User is acting in the agent role it can execute actions over network elements in response to a manager request. It can also send to the manager event notifications about the managed objects. When acting as a manager, the MIS-User entity supervises its network elements by sending actions and receiving notifications. It also supervises agents.

The management services provided by the SIS architecture defines CMIS-like services. There are two services currently implemented: m-event-report (for notification delivery) and m-action (for management operations).

The management architecture defines two classes of objects: alarmRecord and action. The former makes the mapping between alarm syntax of NEs and the platform. The latter corresponds to a string and associated type that informs the operation to be executed by the NE.

The AgentlManager interface [2] relies on the distributed client-server paradigm which emphasizes the quick development of agents. It hides implementation details concerning the communication between agents and S1S. This interface provides transparency in operations like initialization, opening and closing of state report sessions, alarm reporting and failure monitoring of NEs. Initially, the SIS platform was developed for a small set of communication technologies. However, its architecture allows the integration of new technologies such as CORBA and Java that have already incorporated in the agentimanager communication.

The SIS platform was developed at the same time TMN was being conceived. Therefore, part of the ideas proposed in the TMN were able to be incorporated in the SIS system. However, the SIS platform is not fully compliant to the TMN standard. Currently, a complete new management platform could be conceived considering both the standards available nowadays and commercial off-the-shelf software, but not in the early 1990s when there was no management standards and the plant to be managed was composed of different legacy systems.

SIS Architecture: software components ~~ ~~ . . 0 Software groups

- (Core

- ,Applications

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:*PPlicnbn. - Access to managed plant .. .~

0 Division of software mtdm lnafka imd- imaifer components used in the .~ .

SIS platform: ..

- Development tools

f l l c o n

E l m m,m - Operation related tools b " a ~ . r , m " m 1- - Documentation and Intranet,

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Several agents were implemented for the SIS platform and others are under development. Currently there are agents for the following switching systems: Siemens IIWSD, Ericsson AXE, Northern Telecom Cellular, NEAX, Lucent, Tropico R: Tropico RA and Batik Elcom. All of them collect events and are able to execute actions over the managed objects.

We can organize all the software related to SIS in three groups: application, access and core. The core of the system is composed of a number of interfaces to external systems, data base management systems, and manager interfaces. The application group includes programs or tools developed specifically to the system that are called SIS applications. External applications, sometimes representing operation systems, also interface with SIS. The access group is composed of software to interface with the managed elements. One of them is called Agent. Manager and Agent play the conventional role of the managedagent paradigm.

Concerning the development o f the system, it is worthwhile to make a functional division of software components used in the SIS platform in order to see how the several pieces of software fit together. The categories below can be defined:

Development tools Operation related tools - Documentation and Intranet tools

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SIS Architecture: software components

0 The SIS platform relies on the Internet technology and its associated tools: - C and Java languages - Solaris, Linux, and Windows

os's - RPC interprocess

communication - Database management

systems

imranet tools

ex2html

pache hhpd sewer

It is easy to perceive that from the point of view of development a large number of issues must be addressed. Below we list the main tools used in the development process.

The SIS hardware is based on Sun Sparc stations, PC microcomputers, and Solaris, Linux and Windows operating systems. Thus, some of the tools are hardware and software dependent. The main development tools used were: Sparc C and gcc compilers; Java development tools; CVS - code control system; Make - tool for automating tasks based on a set of rules; RPC (Remote Procedure Call) - framework for client/server software development based on RPC paradigm; DBX - debugging environment for Unix; TeleUSE - UIMS (User Interface Management System); TeleUSEDB - UIMS with functionalities for developing database GUI applicatiork; XRT-Table - add-on widget to Motif; SunLink X.25 - tool for managing X.25 link and an API for software development; Sybase SQL Server and Sybase OpenClient - DBMS and the library that provides a C communication interface with the server.

The SIS platform is a distributed system that relies on the Internet technology and has the following characteristics:

It uses the Remote Procedure Call (RPC) paradigm to make interprocess communication; * The system provides a graphical interface to the user; and * It requires a database management system to allow the storage and recovery of events from the telecommunications plant.

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SIS Architecture: software components 0 Development tools play an

important role: - Define all the basis on which the

SIS is built

0:. Some of the tools are effectively part of the SIS system: - They are "linked" to the object

code whereas others are used by developers and operators

0 Provide on-line documentation and technical support through an lntranet

GUI Modules

I

Supervisory modular

Sunllnk X.25 P I

S.rviS0 1"t.rt.C. modules

Other Unix tools, and in some cases CDE tools, can be used during a SIS session. Two of the most used tools are an editor to create configuration files for SIS modules and a mailer system that is SIS mail interface to operators. As part of the SIS platform, an Intranet was set up with these goals in mind. The Web server is from Apache. The browsers installed in the workstations are the Netscape Navigator and in desktops are typically the Microsoft Explorer.

Among the tools mentioned above, some of them are effectively part of the SIS system in the sense that they are "linked" to the object code whereas others are used by developers and operators. Some of the SIS modules that have software components linked to their binaries are: Graphical User Interface (GUI) Modules; Supervisory Modules; Interoperation Module; Database Interaction Module.

A telecommunications plant is a very dynamic system in the sense that network elements are added to or removed from the infrastructure, and functionalities are added or changed frequently. Therefore, the documentation (manuals, tutorials and reference guides) related to both the platform and the telecommunications plant is a very important part of the system that must be kept up-to-date.

All technical documentation related to the SIS platform including the traditional development cycle (analysis, design, implementation, test, and maintenance), release notes, electronic bulletins, etc., were written in LaTeX and previewed with the support tools xdvi, dvips, ghostview, and acroread. Most of these documents were made available in the form of HTML pages using the software package tex2html.

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SIS Service Management (1/2) 6 Service management through Mesox:

0 The proposed solution consists of a set of procedures and the

*:e The SIS platform was integrated to the system of operation

- service to reduce costs and offer a better service for the customers

integration of several systems already in use

management in order to establish communication with network elements and, thus, implement the service requests

e:* The main purpose of the Mesox software is to provide a gateway between the corporative system GOC and the SIS platform

*:* The Mesox solution considered: - the SIS Platform - the service client - different network elements of Telemar's telecommunications plant

SIS Lab UFMG. Brazil

Service management is used to reduce costs and offer a better service for the customers. The ftrst step towards service management at Telemar was the automation of the terminal configuration of switching systems. Originally, the whole procedure was done by Telernar's employees through several steps: customer requests were delivered to company attendants, requests were stored at the General Operation Control (GOC), GOC dispatched service orders in a printed report and, finally, switching system operators typed commands in consoles according to service orders.

The proposed solution consists of a set of procedures and the integration of several systems already in use. Furthermore, it was necessary to develop a new piece of software called Mediator of External Requests (Mesox) responsible for the service integration.

The SIS platform was integrated to the system of operation management in order to establish communication with network elements and, thus, implement the service requests. The main advantage of the SIS platform is its supervising capillarity since it provides a common mechanism of interaction with distinct vendor equipments and is currently installed over a Wide Area Network (WAN) that interconnects several supervisory centers.

The main purpose of the Mesox software is to provide a gateway between the corporative system GOC and the SIS platform. Thus, the initial objective of the Mesox Project was to automate the telephone terminal service which consists of turn-on and turn-off of terminals, cellular phone activation. and supplementary service requests.

- There is no need of immediate service execution, nevertheless the minimum turnaround must be obtained. - There must exist a record mechanism that assures a request delivery.

The solution should consider three distinct environments: the SIS Platform, the service client, and network elements (in this case, switching systems). Currently the General Operation Control system is the service client and it resides in an IBM mainframe running VMiMUMPS and VMICMS.

The SIS management platform is comprised of several processes running under the LJNIX operating system, scattered across several LANs interconnected via a WAN. The agents are distributed among machines in the network and the switching systems are linked to those machines.

The two main requirements regarding service execution were:

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SIS Service Management (212)

+The integrated environments are very different +There is a secure process to send a request ,and receive a resporise Q All transfers are initiated by GOC using specific rules to ensure a correct transfer that avoids race conditions

6 Currently, there is a web interface to Mesox, so a service request dispatched by a system operator can be processed in a matter of minutes

The integrated environments are very different, and thus, the FTP (File Transfer Protocol) was the mechanism chosen to transfer information between the GOC and SIS. Therefore, the information transfer unit is a file with a specific structure.

The files with the service requests are transferred to a specific SIS machine using a specific login and to a specific place in the directory tree. The Mesox process reads these files, search.es the SIS database and finds the SIS manager of the network element and dispatches the action. In the other direction, the agent returns the service results in a message to its manager that forwards it to Mesox which writes down the results in a file. This file can be downloaded by GOC later. The figure above depicts this process which is described below.

All transfers are initiated by GOC using specific rules to ensure a correct file transfer that avoids race conditions. These rules are related to send and read a service request file; to send and receive response files; and to file formats. Each request has a common part and a specific part for each service. Some of the service

request types currently defined are turn-odturn-off, cellular activation, number change, supplementary services and substitution of mobile cellular station. It is possible to include other services by defining other values for the field “request type”. Each service request has a specific fclrmat with appropriate information to execute the service.

In all cases, the information in the specific part is translated by an agent into specific MML (Man-Machine Language) of the supervised network element. The command in MML is then sent to the corresponding network element to be executed. The main advantage of this process is to provide a flat and common application program interface (API).

Due to the diversity of switching equipments installed, the criteria used to implement the services was the number of telephone terminals supported. For instance, almost half of the telephone terminals of the digital plant are Siemens EWSD and Nortel Cellular. In both cases, Mescix is able to supervise 100% of them.

Currently, there is a web interface to Mesox, so a service request dispatched by a system operator can be processed in a matter of minutes.

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SIS Event Operation Tool (1/2) -

.:. .:. High performance

Integration with several management syst ems

*> List filtering for severity, alarms, etc 6 Statistics about events

.:* Centralization and decentralization of the operation

Usability: user-friendly, customization

*:* Event 0 Possibility of opening terminals 0 Ability of opening trouble tickets

3 Robustness, Portability, Modularity

The SIS operation interface i s a graphical operating tool used to manage faults and events i n a telecommunication network. I t must have a good performance, a friendly interface, and must be robust and correct. The interface provides a wide and hierarchical view of the entire telecommunications plant to be managed. I t allows an operator to view different levels o f a plant, ranging from a country region, to a unique supervised entity. For instance, a network element, a process, and so forth. This property allows a smooth transition among distinct views.

The access to information i n the operation units, for queries or modifications, follows restrictions based on access rights that are defined externally in the management system for each user. Besides the entire visualization o f the plant, the SIS operation interface provides the following functionalities: Presentation o f event lists, supervised entities and stations where they are located: Possibility o f defining different filters over lists, as filters o f event severity, equipment specialty, acknowledgment o f alarms, etc; Presentation o f statistics about events; Possibility o f acknowledging alarms by operators with records of who are responsible for them: Capacity o f obtaining information. besides those presented in the lists, such as the name of the operator who acknowledged an alarm: Presentation o f event history; Possibility of opening terminals to execute commands in the supervised. The interface als o enables improvements in its own functionalities as well as integration of new systems quickly and effi ciently.

Concerning usability, i t was assumed that the operator wi l l use the interface continuously along the ti me. Because there are too much possibilities of operation, and a great amount of information is presente d, i t is imponant to have a user-friendly interface. Users can ask for the most relevant information or mo re details if desirable. They also can easily have a general notion o f all operdtion capacities. The access t o each desired operation or information is done quickly and intuitively. by means of icons rather than pl ain text.

One of the strongest aspects of this operation tool is its customization. This property is obtained by m eans o f a functionality that allows users to specify which attributes, from which types or supervised entit ies, the monitored data belongs to. For this, system operators make use of boolean and regular expressi ons, attribute filters, and individual choices o f nodes that represent devices o r a set of devices, which in t urn belong to the topology of the monitored network.

Considering the heterogeneity of the operation environment, the application had also portability as a r equisite. The compiled code is able to run on different operating systems (Linux, Unix or Windows) an d architectures (Intel, Sparc, etc).

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SIS Event Operation Tool (212) *:* Data, Acquisition

- Able to connect directly to network devices

*:e Data Management - Data processing - Statistics and reports

- Operator's interface - Customization

0 Visualization

0 Authentication - User identification

:Data Managementj

generation ~'.........Modu'e ..........

I - I

The SIS operation interface tool architecture is composed of four modules: data acquisition, data management, visualization, and authentication. This module division makes the system easy to be adapted to new functionalities, such as new management protocols. This strategy is critical in large telecommunications plants. The data acquisition module communicates with management systems to make queries or to execute commands. This module has communication subsystems that obtain data through protocols or specific API's. The subsystems can connect directly to the network devices using, for instance, S N M P , as well as requesting data from a server. In this case, using database access (JDBC, ODBC) or remote operations (RPC, RMI, CORBA). Connection to proprietaly systems can be done using vendor's libraries or through some application. The control of tool operation is done by the data management module that has a data structure to store data that represent the managed network topology and the managed entities with their attributes and states. including the associated events. Data are obtained in response to periodical or non-periodical requests from the data management module. All information is,stored in internal data stwctures that have been designed considering the possibility of integration with distinct management systems. This module is also in charge of data processing and of generating reports and statistics.

The authentication module manages the software security and the process of user identification in the various management systems. The visualization module implements the operator's interface. It is responsible for showing all information to users and shows graphical representations of the topology, event lists, statistical graphics, reports, etc.

The development of the SIS platform considered a set of requirements picked up from the operation personnel. This set of requirements guided the specification of the functionality that, by its turn, led the developnlent which was mostly concerned to the following aspects: information model, man-machine interface, data storage, data distribution and data communication network. One of the key factors in the project was the previous joint work between the specification group and the final users. These activities led to a functional specification concerning mostly of interaction functions between users or operators and computers. As a result, some specific functionalities were defined, such as automatic data acquisition. control by commands, plant configuration stored in an integrated database, high quality man-machine interaction through windows, lists, maps, help information. reports, etc.

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Remarks about the development 0 The SIS platform took into

consideration a set of requirements from the operation personnel

0 One of the key factors in the project was the joint work between the specification group and the final users

be an open system

0- & .w. *:* The SIS platform was designed to - " - A

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2 L 0 Different commercial tools were evaluated and used whenever possible

technology and languages such as C and Java

-e,-- - *=,: 6 System based solely on the TCPAP &=+-z-- +..,? t- -? ".

0 0

Of considerable importance was the restriction that the functional architecture should be defined in accordance to the organizational structure of the company. This was also a key factor for the success of the system. Some of the basic requirements identified were: maintain the compatibility with the existing plant; use the system in transmission, switching, access network, infrastructure, and other aspects; integrate the information from various supervisory systems; support special requirements from the clients; be developed according to a modular design; allow know-how acquisition; and make extensive use of commercial hardware and software.

It is clear from this set of requirements that the SIS platform was designed to be an open system. In order to achieve this goal several compromises were assumed. Among them, the fundamental requirements were to use off-the-shelf software components, development tools that were not proprietary, and commercial hardware. The Unix-based environment together with all the Internet network model fill up part of these requirements.

In the design phase, commercial tools were evaluated according to the requirements above. In fact, the whole process was guided by specific evaluations where several characteristics counted towards a final result. In particular, a major tool was chosen after an exhaustive process: the Sybase's Database Management System that supports almost all database needs of the SIS platform.

The initial development of the SIS platform (first version) took four years, including one year for the statements of requirements, one for the functional specification and two for the development, field trials and pilot deployment. Since its first version, delivered in 1993, the SIS management platform is in continuous evolution. The SIS was mostly written in the C language, but other languages such as Java are also used. The entire system has about 1 million lines of code, considering the different programming languages. In this paper! we have presented the SIS telecommunications management platform, a system in constant evolution due to the nature of a telecommunications plant. The platform is in operation, and new functionalities are added frequently. Due to this fact, the volume of information and tasks performed by the system is always increasing. Also the number, diversity and locations of managed elements is increasing. Among all the facts that motivated the construction of a new operation tool by the Federal University of Minas Gerais, the most important ones are the following:

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Conclusions 9 The SIS platform is a system in constant evolution 9 It is one of the key factors for the success of Telemar in the new

competitive telecom market in Brazil 0 It proved that the academia can effectively contribute with high

technology products for the industry 9 The SIS platform has several specific modules that perform different

tasks related to all five functional management areas 0 In this paper we chose to highlight the importance of:

- software components used in the system - the Mesox module responsible for the service management, and - the event operation module

-Management systems are meant to be used unintemptedly, 24 hlday. Most operators will use this tool during all the working period. executing tasks that will become routine after a few workmg days. In such a scenario, usability must be carefully taken into account in the project.

For large or middle-sized telecommunication plants, the amount of simultaneous events allows the specialization of operators by technology, such as switching, transmission, and infrastructure. The supervision can be even more specialized in some cases, where operators are responsible for equipments from a certain manufacturer, for example. -With the use of computer networks and both reliable and high speed links, it is more feasible to centralize the operation of the telecommunications plant, decreasing the number of management centers. Those centers will be bigger, and can be more generic or specialized in determined technologies or categories of equipments. '

* An administrative reorganization, merging regional companies into a national company forced the management systems in operation to be used on larger scales.

The SIS platform has specific modules that perform different tasks related to all five functional management areas. In this paper we chose to highlight the importance of software components used in the system, the Mesox module responsible for the service management, and the event operation module. The software components employed in the SIS proved to be a key factor of success for the system. The very first decision concerning the SIS platform was to use the TCP/IP architecture. As a consequence, all software components used for development, operation, and documentation were based on such technology. The Mesox module is used to satisfy new requirements of automation in the telecommunication plant. Actually, the same mechanism is used to define an interface with a system that collects performance data from network elements. The SIS event operation module provides network operators involved in the management process, a common operation environment. This kind of tool plays a key role in large scale telecommunication and computer networks, which need to integrate a large number of heterogeneous systems and equipments through a common operation envimnment. References

[ I ] Nogueira, Jose M.S.; Meira,Dilmar M.; The SIS Project: A Distributed Pk~tformfor the Inregrution of Telecontniuriication Management Systems, 1n:Proceedings of the IEEEIIFIP NOMS, 1996. [2] R.G.R. Silva and H.C.M. Andrade and J.M.S. Nogueira. Methodology and Experience in Building Powerful Telecommunication Network Management Agents. In Proceedings of 7th IFIPIEEE Internulionui Workshop on Distributed Sistems Operutions & Management (DSOM). Italy, 1996.

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