At the Argentine Department of Justice (Ministerio Público Fiscal de la República Argentina), a project is developed to set up a WAN with national coverage, quality of service, and IP/MPLS/VPN links. The project focuses on quality of service, a direct result from the selected technology. In previous work, studies explored these issues. Hence, the project enabled the implementation of the examined theory. The advantages of MPLS technology are evaluated to determine quality standards in VoIP, videoconference, mission critical appli-cations, e-mail, web access, and others. Other aspects of LANs are analyzed to obtain an availability level compatible to the required needs. The Project in-clude practical recommendations to adequate the LAN to the desired availability levels.IV Workshop Arquitectura, Redes y Sistemas Operativos (WARSO)Red de Universidades con Carreras en Informática (RedUNCI

Castro Lechtaler, Antonio

Crotti, Patricia

Fusario, Rubén J.

García Garino, Carlos

García Guibout, Jorge

English

Servicio de Difusión de la Creación Intelectual

Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The Network at the Department of Justice in Argentina Antonio Castro Lechtaler 2/3, Patricia Crotti 3, Rubén Jorge Fusario 2/3, Carlos García Garino 1, and Jorge García Guibout 1.  1 Instituto Tecnológico Universitario, Universidad Nacional de Cuyo, Mendoza; 2 Escuela Supe-rior Técnica – IESE; 3 Universidad Tecnológica Nacional, Buenos Aires, Argentina. {Antonio Castro Lechtaler acastro@iese.edu.ar, Rubén Fusario rfusario@speddy.com.ar, Patri-cia Crotti pcrotti2002@yahoo.com.ar, Carlos García Garino cgarcia@itu.uncu.edu.ar, Jorge García Guibout jgarcia@itu.uncu.edu.ar} Abstract. At the Argentine Department of Justice (Ministerio Público Fiscal de la República Argentina), a project is developed to set up a WAN with national coverage, quality of service, and IP/MPLS/VPN links. The project focuses on quality of service, a direct result from the selected technology. In previous work, studies explored these issues. Hence, the project enabled the implementa-tion of the examined theory. The advantages of MPLS technology are evaluated to determine quality standards in VoIP, videoconference, mission critical appli-cations, e-mail, web access, and others. Other aspects of LANs are analyzed to obtain an availability level compatible to the required needs. The Project in-clude practical recommendations to adequate the LAN to the desired availabili-ty levels. 1 Design and Implementation of the Network at the Argentine Department of Justice (MPF).1 Background The Project to organize communications adequately at the Argentine Department of Justice (MPF) began in 2006. Its purpose is to link through a WAN all of its offices, taking into account that the District Attorney’s Offices and their administration are nodes of this Department.  The MPF is an institution incorporated in the National Constitution2 in its last reform. Organically, it consists of the Department of Justice and the Office of the Attorney General.                                                  1 MPF stands for Ministerio Público Fiscal (Argentine Department of Justice) 2 The 1994 Reform established that the Department of Justice become one of the authorities of the Argentine Government – along with the Executive, Legislative, and Judiciary Powers– as an independent entity with functional autonomy and financial autarchy (art. 120). The MFP is divided in 16 jurisdictions distributed along the entire country: Bahía Blanca, Buenos Aires, Comodoro Rivadavia, Córdoba, Corrientes, General Roca, La Plata, Mar del Plata, Mendoza, Paraná, Posadas, Resistencia, Rosario, San Martín, Santa Fe, and Tucumán.   The Project is carried out with its own personnel, from the Department of Computer Engineering and Communications under the Department’s Technological Accessibili-ty and Upgrade Plan  Its main objective consists of linking 350 District Attorney Offices and other depen-dencies of the MPF around the country with its own network, providing VoIP, data and video transmission, and institutional applications with an adequate level of infor-mation security.  After a preliminary survey carried out in 2007, the following assumptions are estab-lished for the network design:   Ensure that the chosen technologies could remain current in the long run.  Use Category 6 LAN Ethernet Networks.  Divide the development areas in two: AMBA3 and the rest of the territory.  Implement LANs with local companies.  Select computer technicians by jurisdiction for maintenance and follow-up.  Implement a Network Operations Center: Secure Room.  Provide the LANs with analogous equipment: switches, servers and UPS.  Use a public transmission network for the WAN, working with IP/MPLS links; thus ensuring quality of service.  Monitor and control the network in a centralized manner.  Implement an effective and centralized security policy.  Minimize maintenance costs and decrease reparation times.  Maximize reliability and network availability.  The Project involves hiring specialized human resources and technical personnel as well as the purchase of technology, hardware, and the contracting of services from telecommunications vendors through open bids and current purchase regulation.  In 2008, the MPF Network Implementation Plan was launched. By March 2009, the Plan consists of:    350 linked D.A. Offices.  130 links through IP/MPLS/VPN networks.  3.500 network terminals.  130 LANs.  17 Videoconference equipment sets.                                                  3 Área Múltiple Buenos Aires (AMBA): Consists of the City of Buenos Aires and a significant part of its suburban area, called Gran Buenos Aires. Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The Network at the Department of Justice in Argentina 3  150 Servers.  VoIP service in all D.A. Offices.  Central Operations Control Room and “storage” system: located in Avenida de Mayo 760, including a Backup Processing Center.  Massive storage system with a backup processing center.  User support for institutional applications, network, and telephone services.  Institutional applications for the management of the Judiciary Power in Crimi-nal Law. 2 MPF Network Architecture MPF WAN4 architecture is based on protocols IP-MPLS [1] [2] 5.   Figure 1 MPF Network Architecture  LAN is designed with protocols 802.3 for 100 Mbps, with structured wiring following norm ANSI/EIA/TIA 568, category 6. In the future, this design enables upgrades, up to 1 Gbps. Figure 1 shows the network architecture. Internet connection is centralized in the MPF Central Office,6 and is distributed through the MPF network to 130 destinations.                                                   4 Wide Area Network. 5 Internet Protocol - Multiprotocol Label Switching. 6 Located in Avenida de Mayo 760, Buenos Aires. The network enables VoIP communication among all MPF offices using three voice channels per office.  Data and voice transmission is full mesh for the network nodes, as well as videocon-ference among the head offices and the sixteen Prosecutor offices.  The network has a structure of terrestrial physical fiber optic links, copper and/or digital microwave, linking the different nodes and following transmission speeds ranging from 512 Kbps to 4 Mbps. The link between the Buenos Aires central node with the IP/MPLS network of the Internet provider is 100 Mbps.  The basis for this architecture relies on MPLS [3] performance, granting:   An adequate security level.  Bandwidth on demand.  Access to the network from any place with Internet access.  Furthermore, the architecture also offers the following convenient features:   “Full mesh” architecture.  Quality of Service: Using MPLS the network controls the quality of service.  Voice, data, video, and mission critical application transmission capabilities.  Cost reduction in telephone services, videoconferences, and others.  Among the main services provided, we can mention:   Multimedia: voice and video, and video streaming.  VoIP.  Reliable safeguarding of MPF information.  Secure Access to internet through firewalls.  Access to databases and applications from other government offices.  Videoconference  Institutional electronic mail  Given the required characteristics for the network traffic, the services provided are:   Multimedia Traffic. Minimum delay and jitter. In addition, delayed packets are deleted.  Videoconference Traffic. Similar to multimedia traffic but with less priority.  High Priority Traffic. Sensitive to Time Out, for critical applications.  Normal Priority Traffic. For the transmission of files, databases, and systems in general.  Low Priority Traffic. Used in electronic mail and internet. Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The Network at the Department of Justice in Argentina 5 3 Features of the Network Level of Service with Internet Access. Service provides Internet access with a transmission speed of 40 Mbps and upgrading capabilities. Transmission is digital, with no tolerance for analog lines.  Internet access is through the Central Office. From that point, service is granted to all other offices through the WAN of the MPF.  Total bandwidth is distributed between domestic and international access, assigning it dynamically to ensure a “Committed Information Rate” (CIR %) for both cases, ac-cording to the following ratios: TOTALimumNACimumNACNACBWBWCIRCIR)(min)(min(%)  ; TOTALimumINTimumINTINTBWBWCIRCIR)(min)(min(%)   BWTOTAL: Transmission speed of each link  BWNAC(minimum) and BWINT(minimum): Desired Domestic and International bandwidth. Their sum never exceeds the total bandwidth (BWTOTAL).  The Network guarantees a CIRNAC(minimum) (%) = 95% and CIRINT(minimum) (%) = 95%.  The network also complies with the following features to provide an adequate quality of service:   Minimum link availability of 99,7 % -- measured annually – and 99,5 % if measured per trimester.  BER = 10-7.   Figure 2  Average Minimum Time between Failures – MTmBF, maximum per month: 30 hours.  Minimum Time between Failures – TmBF, maximum per month: 15 hours.   Maximum Time for Restoration of Service – TMRS, less than 2 hours per month.  Parameters used in the estimation:   Average Minimum Time between Failures- MTmBF:  Constant defining the average tolerance between two successive failures. MTBF > MTmBF must hold Where: Minimum Time between Failures– MTBF is defined as nTBFMTBFni 1 n = occurrence of failures in a month. TBFi = Time elapsed between failure (i) and failure (i-1).  Time between failures - TBF:  Constant defining the time between two consecutive failures. TBFi > TmBF must hold, where:   1 iii FTFTTBF   Minimum Time between failures (TmBF). Constant defining the minimum tolerance between two consecutive failures.  Maximum Time for Restoration of Service – TMRS. Constant defining the maximum tolerance for the restoration of service. 4 Performance Trials 4.1 Connectivity Test Round trip times between a single station connected to the router at the Central Office and the sites detailed in Table 1 are tested. The resulting times are under 700 [ms] for international sites and 300 [ms] for domestic sites.  List of Sites uc.cache.nlanr.net www.cisco.com ns.uu.net www.vend.org www.fedworld.gov www.presidencia.gov.ar www.mre.gov.br www.ibge.gov.br www.sebrae.com.br www.presidencia.cl Table 1  Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The Network at the Department of Justice in Argentina 7 Tests run through ICMP (PING) with packets 1024-byte long, sent in three separate opportunities, ten packets each. 4.2 Bandwidth Test The following test is required:  The sum of FTP transmission rates between a single station connected to the access router at the Central Office and the sites detailed in Table 2.  List of Sites ftp.netscape.com ftp.oracle.com ftp.sco.com ftp.freebsd.org ftp.openbsd.org ftp.sun.com ftp.hp.com ftp.cheyenne.com ftp.conexion.com  Table 2   The sum should are not less than 90% of the nominal available bandwidth in the channel setup by the provider, transferring files of at least 7 MB. 4.3 Level of Service The following features are considered to determine Quality of Service [4] [5]:   Guaranteed Delivery.  Transmission Error Recovery.  Congestion Control.  Guaranteed bandwidth.  Flow control.  These basic principles vary when facing the need to implement mail, chat, VoIP, and multimedia. The latter require other control parameters. Thus, the following features are considered:   Delay: Period of time in transit through a path, where the amount of jumps in-volved becomes a significant parameter.  Jitter: Difference in the delay through a path, originated by network instability.  Packet Loss: Should be restricted.  Priority: To ensure further the adequate delivery of critical traffic.  Availability: Percentage of time in which service is operative.  The MPLS Network has three levels for quality of service:   Level 1: Best Effort type for Internet and e-mail traffic.  Level 2: Reliable data traffic, for MPF institutional applications.  Level 3: Multimedia, voice, and video traffic.  Guaranteed values in the following parameters are determined to achieve the desired quality of service:   Packet Loss.  Delay or Latency.  Jitter.  Based on these criteria, the parameters listed below are established:   WAN IP/MPLS/VPN link availability of 99,5 % measured annually and 99.2% monthly.  BER = 10-7  Average Minimum Time between Failures – MTmBF, per month: 40 hours.  Minimum Time between Failures – TmBF, per month: 30 hours.  Maximum Time for Restoration of Service – TMRS, per month: less than 4 hours in AMBA and less than 6 hours in the rest of the country.  Real time reporting is available to accomplish effective control. The system reports:   Services (use of service graphs, traffic)  Failures: list of failures, beginning date and time, final date and time, affected service (link), date and time of failure notice, failure origin, comments.  Line use: line use percentage in bps, incoming and outgoing frames, compared to the total available bandwidth.  Availability: Percentage of time in service, disaggregated per service. tTS = Total time of Service.  tSE = Total time of Effective Service. tTI = tTS - tSE (Total Unavailability Time). 100*tTStSE(%)tyAv ailabili   5 Concluding Remarks. Based on the study of the network architecture developed at the Argentine Ministry of Justice, the following key features are determined for network quality of service:   Full Mesh design in the architecture, IP / VPN / MPLS, enabling the delivery of a wide range of service based on IP, in theoretical range of 56 Kbps to 40 Gbps. Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The Network at the Department of Justice in Argentina 9  Precise parameter definition to require the most adequate service for the varie-ty of traffic and formats transmitted in the network, and to guarantee service availability to all offices around the country.  Quality of Traffic ensured to critical mission applications with a WAN packet loss of less than 1%, called “Gold Traffic” by the company providing the ser-vices.  Best Effort non priority data traffic, called “Bronze Traffic” by the service provider, with a packet loss level higher than 1%. The services provided on this quality level are internet surfing and electronic mail.  Multimedia Traffic with two main services: VoIP and Videoconferencing. The services use the traffic called “Multimedia” by the provider which should guarantee isochrone signal transmission. Thus, packet loss, jitter, and delay need consideration. A packet loss lower than 0.5% is provided. Domestic traf-fic maximum delay is 200 mseg and jitter less than 30 seconds. International Traffic has a delay up to 300 mseg, and maintains the same value for jitter as the domestic case.  Quality of service complemented with an appropriate definition of security policies, following standards and norms and their implementation. These poli-cies are available to all network users to better visualize and understand the network.  Central control room infrastructure with modern security features and equip-ment protection to permanently guarantee operations at the data processing center of the MPF.  Availability of the network adequate to the operative needs of the organiza-tions. TMBF availability qualifies the level of failure of the equipment and as-sociated software, The TMRS expresses the average time for each failure repa-ration.  Based on quality of service, the network at the MPF ensures:   Efficient and reliable transmission of voice, video, and data.  MPF data transmission and safe storage.  Resource optimization based on savings in communications, personnel, and in-formation costs.  Implementation of management systems which optimize MPF operations in real time.  Finally, this network is the practical implementation supported in previous work de-veloped by this Research Group [6] [7] which focuses on achievable advantages in class and quality of service 6 Acknowledgements. The financial support provided by Agencia Nacional para la Promoción Científica y Tecnológica and CITEFA (Project PICTO 11-0821, Préstamo BID 1726 OC-AR) is gratefully acknowledged and the contribution of Doctor Adrián Marchisio, Secretary of Institutional Coordination to the MPF. 7 References. [1] Adriana Andrades, Impacto de la tecnología MPLS sobre infraestructuras de redes basadas en frame relay. Télématique: Revista Electrónica de Estudios Telemáticos, ISSN 8156-4194, Vol. 3, Nº. 2, 2004, pags. 14-24 [2] Hesselbach Serra, Xavier; Mónica Huerta; Calderón Cortés, Oscar Josué. Proble-mas abiertos en MPLS. Migración, Protección, Gestión de Recursos y Balanceo de Carga. In: III Workshop en Redes MPLS, 2004, Girona. III Workshop en Redes MPLS. Girona: Edicions a Petició, SL, 2004. v. 1, p. 21-33. [3] Mónica Huerta; Calderón Cortés, Oscar Josué; Hesselbach Serra, Xavier. Model for flow allocation and cost minimization in MPLS networks. In: Fifth International Caracas Conference on Devices, Circuits and Systems, 2004, República Dominicana. Proceedings of the fifth IEEE International Caracas Conference on Devices, Circuits and Systems. Piscataway: IEEE, 2004. v. 1, p. 244-248.  [4] Huerta, Monica; Hesselbach, Xavier; Fabregat, Ramon; Padilla, Jhon; Ravelo, Oswaldo; Clotet, Roger Minimization of Congestion in MPLS Networks by means of Flows Optimization Techniques. Transactions, IEEE (Revista IEEE America Latina)  Volume 5, Issue 5, Sept. 2007 Page(s):352 – 359 Digital Object Identifier 0.1109/TLA.2007.4378528 [5] Yezid Donoso Meisel1, Ramón Fabregat, José Luis Marzo, Eusebi. Multidifusión IP sobre MPLS sin y con QoS: propuesta y análisis de rendimiento [6] E. Carrara, A. Castro Lechtaler, R. Fusario, C. García Garino, and J. Mon. An Overview of MPLS Technology: Quality of Service and Traffic Engineering. ISBN 978 - 950 – 656 – 109 – 3. Pp. 23 to 34. Corrientes. October 2007. [7] A. Arroyo Arzubi, A. Castro Lechtaler, R. Fusario, C. García Garino y J. García Guibout. MPLS Technology: Class of Service. ISBN 978 - 987 - 24611 - 0 - 2. pp. 283 to 294. Chilecito. October 2008. 

Quality of service and availability in a full mesh WAN using IP/MPLS : Case study: the network at the Department of Justice in Argentina

SEDICI - Repositorio de la UNLP

Quality of Service and Availability in a Full Mesh WAN 
using IP/MPLS. Case Study: The Network at the Department 
of Justice in Argentina 
Antonio Castro Lechtaler 2/3, Patricia Crotti 3, Rubén Jorge Fusario 2/3, Carlos García 
Garino 1, and Jorge García Guibout 1.  
1 Instituto Tecnológico Universitario, Universidad Nacional de Cuyo, Mendoza; 2 Escuela Supe-
rior Técnica – IESE; 3 Universidad Tecnológica Nacional, Buenos Aires, Argentina. 
{Antonio Castro Lechtaler acastro@iese.edu.ar, Rubén Fusario rfusario@speddy.com.ar, Patri-
cia Crotti pcrotti2002@yahoo.com.ar, Carlos García Garino cgarcia@itu.uncu.edu.ar, Jorge 
García Guibout jgarcia@itu.uncu.edu.ar} 
Abstract. At the Argentine Department of Justice (Ministerio Público Fiscal de 
la República Argentina), a project is developed to set up a WAN with national 
coverage, quality of service, and IP/MPLS/VPN links. The project focuses on 
quality of service, a direct result from the selected technology. In previous 
work, studies explored these issues. Hence, the project enabled the implementa-
tion of the examined theory. The advantages of MPLS technology are evaluated 
to determine quality standards in VoIP, videoconference, mission critical appli-
cations, e-mail, web access, and others. Other aspects of LANs are analyzed to 
obtain an availability level compatible to the required needs. The Project in-
clude practical recommendations to adequate the LAN to the desired availabili-
ty levels. 
1 Design and Implementation of the Network at the Argentine 
Department of Justice (MPF).1 Background 
The Project to organize communications adequately at the Argentine Department of 
Justice (MPF) began in 2006. Its purpose is to link through a WAN all of its offices, 
taking into account that the District Attorney’s Offices and their administration are 
nodes of this Department. 
 
The MPF is an institution incorporated in the National Constitution2 in its last reform. 
Organically, it consists of the Department of Justice and the Office of the Attorney 
General. 
                                                 
1 MPF stands for Ministerio Público Fiscal (Argentine Department of Justice) 
2 The 1994 Reform established that the Department of Justice become one of the authorities of 
the Argentine Government – along with the Executive, Legislative, and Judiciary Powers– as 
an independent entity with functional autonomy and financial autarchy (art. 120). 
The MFP is divided in 16 jurisdictions distributed along the entire country: Bahía 
Blanca, Buenos Aires, Comodoro Rivadavia, Córdoba, Corrientes, General Roca, La 
Plata, Mar del Plata, Mendoza, Paraná, Posadas, Resistencia, Rosario, San Martín, 
Santa Fe, and Tucumán.  
 
The Project is carried out with its own personnel, from the Department of Computer 
Engineering and Communications under the Department’s Technological Accessibili-
ty and Upgrade Plan 
 
Its main objective consists of linking 350 District Attorney Offices and other depen-
dencies of the MPF around the country with its own network, providing VoIP, data 
and video transmission, and institutional applications with an adequate level of infor-
mation security. 
 
After a preliminary survey carried out in 2007, the following assumptions are estab-
lished for the network design: 
 
 Ensure that the chosen technologies could remain current in the long run. 
 Use Category 6 LAN Ethernet Networks. 
 Divide the development areas in two: AMBA3 and the rest of the territory. 
 Implement LANs with local companies. 
 Select computer technicians by jurisdiction for maintenance and follow-up. 
 Implement a Network Operations Center: Secure Room. 
 Provide the LANs with analogous equipment: switches, servers and UPS. 
 Use a public transmission network for the WAN, working with IP/MPLS links; 
thus ensuring quality of service. 
 Monitor and control the network in a centralized manner. 
 Implement an effective and centralized security policy. 
 Minimize maintenance costs and decrease reparation times. 
 Maximize reliability and network availability. 
 
The Project involves hiring specialized human resources and technical personnel as 
well as the purchase of technology, hardware, and the contracting of services from 
telecommunications vendors through open bids and current purchase regulation. 
 
In 2008, the MPF Network Implementation Plan was launched. By March 2009, the 
Plan consists of:  
 
 350 linked D.A. Offices. 
 130 links through IP/MPLS/VPN networks. 
 3.500 network terminals. 
 130 LANs. 
 17 Videoconference equipment sets. 
                                                 
3 Área Múltiple Buenos Aires (AMBA): Consists of the City of Buenos Aires and a significant 
part of its suburban area, called Gran Buenos Aires. 
Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The 
Network at the Department of Justice in Argentina 3 
 150 Servers. 
 VoIP service in all D.A. Offices. 
 Central Operations Control Room and “storage” system: located in Avenida de 
Mayo 760, including a Backup Processing Center. 
 Massive storage system with a backup processing center. 
 User support for institutional applications, network, and telephone services. 
 Institutional applications for the management of the Judiciary Power in Crimi-
nal Law. 
2 MPF Network Architecture 
MPF WAN4 architecture is based on protocols IP-MPLS [1] [2] 5. 
 
 
Figure 1 MPF Network Architecture 
 
LAN is designed with protocols 802.3 for 100 Mbps, with structured wiring following 
norm ANSI/EIA/TIA 568, category 6. In the future, this design enables upgrades, up 
to 1 Gbps. Figure 1 shows the network architecture. 
Internet connection is centralized in the MPF Central Office,6 and is distributed 
through the MPF network to 130 destinations. 
 
                                                 
4 Wide Area Network. 
5 Internet Protocol - Multiprotocol Label Switching. 
6 Located in Avenida de Mayo 760, Buenos Aires. 
The network enables VoIP communication among all MPF offices using three voice 
channels per office. 
 
Data and voice transmission is full mesh for the network nodes, as well as videocon-
ference among the head offices and the sixteen Prosecutor offices. 
 
The network has a structure of terrestrial physical fiber optic links, copper and/or 
digital microwave, linking the different nodes and following transmission speeds 
ranging from 512 Kbps to 4 Mbps. The link between the Buenos Aires central node 
with the IP/MPLS network of the Internet provider is 100 Mbps. 
 
The basis for this architecture relies on MPLS [3] performance, granting: 
 
 An adequate security level. 
 Bandwidth on demand. 
 Access to the network from any place with Internet access. 
 
Furthermore, the architecture also offers the following convenient features: 
 
 “Full mesh” architecture. 
 Quality of Service: Using MPLS the network controls the quality of service. 
 Voice, data, video, and mission critical application transmission capabilities. 
 Cost reduction in telephone services, videoconferences, and others. 
 
Among the main services provided, we can mention: 
 
 Multimedia: voice and video, and video streaming. 
 VoIP. 
 Reliable safeguarding of MPF information. 
 Secure Access to internet through firewalls. 
 Access to databases and applications from other government offices. 
 Videoconference 
 Institutional electronic mail 
 
Given the required characteristics for the network traffic, the services provided are: 
 
 Multimedia Traffic. Minimum delay and jitter. In addition, delayed packets are 
deleted. 
 Videoconference Traffic. Similar to multimedia traffic but with less priority. 
 High Priority Traffic. Sensitive to Time Out, for critical applications. 
 Normal Priority Traffic. For the transmission of files, databases, and systems 
in general. 
 Low Priority Traffic. Used in electronic mail and internet. 
Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The 
Network at the Department of Justice in Argentina 5 
3 Features of the Network Level of Service with Internet 
Access. 
Service provides Internet access with a transmission speed of 40 Mbps and upgrading 
capabilities. Transmission is digital, with no tolerance for analog lines. 
 
Internet access is through the Central Office. From that point, service is granted to all 
other offices through the WAN of the MPF. 
 
Total bandwidth is distributed between domestic and international access, assigning it 
dynamically to ensure a “Committed Information Rate” (CIR %) for both cases, ac-
cording to the following ratios: 
TOTAL
imumNAC
imumNACNAC
BW
BW
CIRCIR
)(min
)(min(%)  ; 
TOTAL
imumINT
imumINTINT
BW
BW
CIRCIR
)(min
)(min(%)   
BWTOTAL: Transmission speed of each link 
 
BWNAC(minimum) and BWINT(minimum): Desired Domestic and International bandwidth. 
Their sum never exceeds the total bandwidth (BWTOTAL). 
 
The Network guarantees a CIRNAC(minimum) (%) = 95% and CIRINT(minimum) (%) = 95%. 
 
The network also complies with the following features to provide an adequate quality 
of service: 
 
 Minimum link availability of 99,7 % -- measured annually – and 99,5 % if 
measured per trimester. 
 BER = 10-7. 
 
 
Figure 2 
 Average Minimum Time between Failures – MTmBF, maximum per month: 
30 hours. 
 Minimum Time between Failures – TmBF, maximum per month: 15 hours.  
 Maximum Time for Restoration of Service – TMRS, less than 2 hours per 
month. 
 
Parameters used in the estimation: 
 
 Average Minimum Time between Failures- MTmBF:  
Constant defining the average tolerance between two successive failures. 
MTBF > MTmBF must hold 
Where: 
Minimum Time between Failures– MTBF is defined as 
n
TBF
MTBF
n
i
 1
 
n = occurrence of failures in a month. 
TBFi = Time elapsed between failure (i) 
and failure (i-1). 
 Time between failures - TBF:  
Constant defining the time between two consecutive failures. TBFi > TmBF 
must hold, where: 
  1 iii FTFTTBF  
 Minimum Time between failures (TmBF). 
Constant defining the minimum tolerance between two consecutive failures. 
 Maximum Time for Restoration of Service – TMRS. 
Constant defining the maximum tolerance for the restoration of service. 
4 Performance Trials 
4.1 Connectivity Test 
Round trip times between a single station connected to the router at the Central Office 
and the sites detailed in Table 1 are tested. The resulting times are under 700 [ms] for 
international sites and 300 [ms] for domestic sites. 
 
List of Sites 
uc.cache.nlanr.net www.cisco.com 
ns.uu.net www.vend.org 
www.fedworld.gov www.presidencia.gov.ar 
www.mre.gov.br www.ibge.gov.br 
www.sebrae.com.br www.presidencia.cl 
Table 1 
 
Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The 
Network at the Department of Justice in Argentina 7 
Tests run through ICMP (PING) with packets 1024-byte long, sent in three separate 
opportunities, ten packets each. 
4.2 Bandwidth Test 
The following test is required: 
 
The sum of FTP transmission rates between a single station connected to the access 
router at the Central Office and the sites detailed in Table 2. 
 
List of Sites 
ftp.netscape.com ftp.oracle.com 
ftp.sco.com ftp.freebsd.org 
ftp.openbsd.org ftp.sun.com 
ftp.hp.com ftp.cheyenne.com 
ftp.conexion.com  
Table 2  
 
The sum should are not less than 90% of the nominal available bandwidth in the 
channel setup by the provider, transferring files of at least 7 MB. 
4.3 Level of Service 
The following features are considered to determine Quality of Service [4] [5]: 
 
 Guaranteed Delivery. 
 Transmission Error Recovery. 
 Congestion Control. 
 Guaranteed bandwidth. 
 Flow control. 
 
These basic principles vary when facing the need to implement mail, chat, VoIP, and 
multimedia. The latter require other control parameters. Thus, the following features 
are considered: 
 
 Delay: Period of time in transit through a path, where the amount of jumps in-
volved becomes a significant parameter. 
 Jitter: Difference in the delay through a path, originated by network instability. 
 Packet Loss: Should be restricted. 
 Priority: To ensure further the adequate delivery of critical traffic. 
 Availability: Percentage of time in which service is operative. 
 
The MPLS Network has three levels for quality of service: 
  Level 1: Best Effort type for Internet and e-mail traffic. 
 Level 2: Reliable data traffic, for MPF institutional applications. 
 Level 3: Multimedia, voice, and video traffic. 
 
Guaranteed values in the following parameters are determined to achieve the desired 
quality of service: 
 
 Packet Loss. 
 Delay or Latency. 
 Jitter. 
 
Based on these criteria, the parameters listed below are established: 
 
 WAN IP/MPLS/VPN link availability of 99,5 % measured annually and 99.2% 
monthly. 
 BER = 10-7 
 Average Minimum Time between Failures – MTmBF, per month: 40 hours. 
 Minimum Time between Failures – TmBF, per month: 30 hours. 
 Maximum Time for Restoration of Service – TMRS, per month: less than 4 
hours in AMBA and less than 6 hours in the rest of the country. 
 
Real time reporting is available to accomplish effective control. The system reports: 
 
 Services (use of service graphs, traffic) 
 Failures: list of failures, beginning date and time, final date and time, affected 
service (link), date and time of failure notice, failure origin, comments. 
 Line use: line use percentage in bps, incoming and outgoing frames, compared 
to the total available bandwidth. 
 Availability: Percentage of time in service, disaggregated per service. 
tTS = Total time of Service.  
tSE = Total time of Effective Service. 
tTI = tTS - tSE (Total Unavailability Time). 
100*
tTS
tSE
(%)tyAv ailabili   
5 Concluding Remarks. 
Based on the study of the network architecture developed at the Argentine Ministry of 
Justice, the following key features are determined for network quality of service: 
 
 Full Mesh design in the architecture, IP / VPN / MPLS, enabling the delivery 
of a wide range of service based on IP, in theoretical range of 56 Kbps to 40 
Gbps. 
Quality of Service and Availability in a Full Mesh WAN using IP/MPLS. Case Study: The 
Network at the Department of Justice in Argentina 9 
 Precise parameter definition to require the most adequate service for the varie-
ty of traffic and formats transmitted in the network, and to guarantee service 
availability to all offices around the country. 
 Quality of Traffic ensured to critical mission applications with a WAN packet 
loss of less than 1%, called “Gold Traffic” by the company providing the ser-
vices. 
 Best Effort non priority data traffic, called “Bronze Traffic” by the service 
provider, with a packet loss level higher than 1%. The services provided on 
this quality level are internet surfing and electronic mail. 
 Multimedia Traffic with two main services: VoIP and Videoconferencing. The 
services use the traffic called “Multimedia” by the provider which should 
guarantee isochrone signal transmission. Thus, packet loss, jitter, and delay 
need consideration. A packet loss lower than 0.5% is provided. Domestic traf-
fic maximum delay is 200 mseg and jitter less than 30 seconds. International 
Traffic has a delay up to 300 mseg, and maintains the same value for jitter as 
the domestic case. 
 Quality of service complemented with an appropriate definition of security 
policies, following standards and norms and their implementation. These poli-
cies are available to all network users to better visualize and understand the 
network. 
 Central control room infrastructure with modern security features and equip-
ment protection to permanently guarantee operations at the data processing 
center of the MPF. 
 Availability of the network adequate to the operative needs of the organiza-
tions. TMBF availability qualifies the level of failure of the equipment and as-
sociated software, The TMRS expresses the average time for each failure repa-
ration. 
 
Based on quality of service, the network at the MPF ensures: 
 
 Efficient and reliable transmission of voice, video, and data. 
 MPF data transmission and safe storage. 
 Resource optimization based on savings in communications, personnel, and in-
formation costs. 
 Implementation of management systems which optimize MPF operations in 
real time. 
 
Finally, this network is the practical implementation supported in previous work de-
veloped by this Research Group [6] [7] which focuses on achievable advantages in 
class and quality of service 
6 Acknowledgements. 
The financial support provided by Agencia Nacional para la Promoción Científica y 
Tecnológica and CITEFA (Project PICTO 11-0821, Préstamo BID 1726 OC-AR) is 
gratefully acknowledged and the contribution of Doctor Adrián Marchisio, Secretary 
of Institutional Coordination to the MPF. 
7 References. 
[1] Adriana Andrades, Impacto de la tecnología MPLS sobre infraestructuras de redes 
basadas en frame relay. Télématique: Revista Electrónica de Estudios Telemáticos, 
ISSN 8156-4194, Vol. 3, Nº. 2, 2004, pags. 14-24 
[2] Hesselbach Serra, Xavier; Mónica Huerta; Calderón Cortés, Oscar Josué. Proble-
mas abiertos en MPLS. Migración, Protección, Gestión de Recursos y Balanceo de 
Carga. In: III Workshop en Redes MPLS, 2004, Girona. III Workshop en Redes 
MPLS. Girona: Edicions a Petició, SL, 2004. v. 1, p. 21-33. 
[3] Mónica Huerta; Calderón Cortés, Oscar Josué; Hesselbach Serra, Xavier. Model 
for flow allocation and cost minimization in MPLS networks. In: Fifth International 
Caracas Conference on Devices, Circuits and Systems, 2004, República Dominicana. 
Proceedings of the fifth IEEE International Caracas Conference on Devices, Circuits 
and Systems. Piscataway: IEEE, 2004. v. 1, p. 244-248.  
[4] Huerta, Monica; Hesselbach, Xavier; Fabregat, Ramon; Padilla, Jhon; Ravelo, 
Oswaldo; Clotet, Roger Minimization of Congestion in MPLS Networks by means of 
Flows Optimization Techniques. Transactions, IEEE (Revista IEEE America Latina)  
Volume 5, Issue 5, Sept. 2007 Page(s):352 – 359 Digital Object Identifier 
0.1109/TLA.2007.4378528 
[5] Yezid Donoso Meisel1, Ramón Fabregat, José Luis Marzo, Eusebi. Multidifusión 
IP sobre MPLS sin y con QoS: propuesta y análisis de rendimiento 
[6] E. Carrara, A. Castro Lechtaler, R. Fusario, C. García Garino, and J. Mon. An 
Overview of MPLS Technology: Quality of Service and Traffic Engineering. ISBN 
978 - 950 – 656 – 109 – 3. Pp. 23 to 34. Corrientes. October 2007. 
[7] A. Arroyo Arzubi, A. Castro Lechtaler, R. Fusario, C. García Garino y J. García 
Guibout. MPLS Technology: Class of Service. ISBN 978 - 987 - 24611 - 0 - 2. pp. 
283 to 294. Chilecito. October 2008. 


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Quality of service and availability in a full mesh WAN using IP/MPLS : Case study: the network at the Department of Justice in Argentina

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