UNCLASSIFIED/UNLIMITED Quality of Service Support in IPv6-based Military Networks with Limited Bandwidth Links1 Marek Amanowicz Military Communication Institute 05-130 Zegrze POLAND [email protected] Peter Sevenich Institute for Communications Information Processing and Ergonomics (FKIE) 53343 Wachtberg GERMANY [email protected] Jacek Jarmakiewicz Markus Pilz Military University of Technology Computer Science Kaliskiego 2 University of Bonn 00-908 Warsaw Bonn POLAND GERMANY [email protected] [email protected] ABSTRACT Adaptation of commercial Internet solutions for providing effective mechanisms supporting user’s mobility, information security and quality of services is the subject of several research projects running both nationally and internationally. From the military perspective, the IPv6-based solutions must provide required level of performance for networks deployed in specific tactical environment. Such networks - by their nature - are relatively unreliable and varying, both in location and topology. In tactical networks, significant amount of data, both time-critical and non-real time, has to be exchanged over disadvantage (also in terms of bandwidth limitation) links. This calls for improving the standard IPv6 mechanisms and elaboration of new effective methods of QoS support. The NATO Information System Technology Panel ongoing Support Project (PL-IST-003) on “Implementation of IPv6 Protocol for Tactical Interoperable Communications Networks – TICNET” enters into these efforts. The paper gives an overview of the works on improving QoS support in IPv6-based military networks that are performed jointly by the teams from German and Polish research establishments. In particular, it presents the basic issues of providing QoS for both time-critical and non-real time services in tactical networks with limited bandwidth links and discusses the measurement methodology of prediction of available bandwidth. It also describes the results of technical experiments and simulations, aiming at evaluation the efficiency of QoS support mechanisms elaborated within the Project. 1 This paper has been prepared with the framework of Grant No. 0 T00A 16 25 founded by the Polish Scientific Research Committee and the NATO IST Panel Support Project PL-IST-003. Amanowicz, M.; Sevenich, P.; Jarmakiewicz, J.; Pilz, M. (2006) Quality of Service Support in IPv6-based Military Networks with Limited Bandwidth Links. In Military Communications (pp. 15-1 – 15-12). Meeting Proceedings RTO-MP-IST-054, Paper 15. Neuilly-sur-Seine, France: RTO. Available from: http://www.rto.nato.int/abstracts.asp. RTO-MP-IST-054 15 - 1 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED Quality of Service Support in IPv6-based Military Networks with Limited Bandwidth Links 1.0 BACKGROUND Military transformation process of the war fighting capabilities adjustment to new emerging strategic challenges leads to fundamental changes in military doctrine and operational concepts, military forces organisation, war fighters’ equipment and training. Nowadays, the strategic thinking is mostly stimulated by the new challenging concept of operation, called Network Enabled Capabilities (NEC). It generates increased combat power by networking sensors, decision makers and shooters to achieve shared awareness, increased speed of command, higher tempo of operations, greater lethality, increased survivability, and a degree of self-synchronisation. This concept requires essential changes in military thinking as well as strong technological support. Interoperable communications and information infrastructure is a core of net-centric operations. It enables creation of shared battlespace awareness and knowledge, which is leveraged by new adaptive command and control processes and self-synchronizing forces. The dynamics of military information flow demands the reliability and robustness of the information grid. However, military communication infrastructure is relatively unreliable and timely varying both in location and topology. This call for development of effective mechanisms and related procedures that allow deploying communication networks, which operate in a fashion that scales to the net-centric operations. A significant part of these activities refers to adaptation of commercial Internet solutions for developing tactical communications systems. It is expected, that implementation of IPv6 protocol will significantly contribute to achieving this goal, providing the mechanisms supporting user mobility, information security and quality of services. However, IPv6 protocol requires detailed investigation of its efficiency and need to be seriously verified against performance in environments with unique link characteristics of tactical networks. That is a subject of several research investigations performed both nationally and internationally. The NATO Information System Technology Panel ongoing Support Project on “Implementation of IPv6 Protocol for Tactical Interoperable Communications Networks – TICNET” enters into these efforts. The works performed by research teams from Research Institute for Communications, Information Processing and Ergonomics (FKIE) from Germany, Military Communication Institute (MCI) and Military University of Technology (MUT) from Poland, are focused on identification the gaps and providing improvements to standard IPv6 mechanism, especially resulted in: • elaboration effective procedures of QoS support providing both secure time-critical and non-real- time data over IPv6-based mobile networks with limited bandwidth links, • creation the technical infrastructure and simulation environment for QoS mechanisms verification and validation, both at protocol and system level. Additionally, the Project gives an opportunity for fostering collaboration between the Polish and German research establishments, improving their scientific base and effective usage of the research potential for national and NATO defence needs. In this paper, we discuss the basic issues of providing QoS support in tactical networks with narrowband links (for instance ISDN or HF links) and shortly resume the mechanisms implemented in the Network Adapter (NA), such as header and data compression, traffic multiplexing and prioritisation. The methodology of prediction the end-to-end bandwidth that is available for handling of non-time critical traffic has been used for evaluation of the NA performance in the presence of both time critical and non- prioritised data. Some measurement data are discussed in section 3. Then, we describe the technical experiments performed with the aim of evaluation the QoS metrics while multiplexing time-critical and non-real time data in the narrowband link. The experiments have been performed in testbedding environment with two Network Adapters located in FKIE (Germany) and MCI (Poland) and connected over the ISDN link. A general description of the testbed configuration, testing scenarios and obtained results is given in section 4.1. 15 - 2 RTO-MP-IST-054 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED Quality of Service Support in IPv6-based Military Networks with Limited Bandwidth Links In section 4.2 we describe the OPNET simulation model that have been used for evaluation the efficiency of the proposed mechanism of QoS support in complex environment. In the paper, we shortly describe the model architecture as well as scenarios used for the model validation. We also present the results of our simulations and the comparison with data obtained during technical experiments. In conclusion, we present our comments on applicability of described solutions in tactical networks and specify the way ahead. 2.0 QoS SUPPORT IN TACTICAL ENVIRONMENT 2.1 Bandwidth limitation The military users needs for providing the increasing amount of different types of information (including multimedia) with acceptable quality level from sensors to the engage units result in demands for deploying the networks with higher and higher bandwidth. Today, advances in information, communication and optoelectronic technologies allow achieving a balance between provision and consumption of the bandwidth. Additionally, many researches carried out under NATO and EU auspices are focused on developing effective methods of QoS support in Internet and other types of IP-based networks. However, a direct implementation of these solutions in military networks is limited due to security, mobility or interoperability issues, but also because of the nature of tactical communication systems that widely use low bandwidth links (e.g. ISDN, HF or SATCOM). The bandwidth limitations cause that specific method of QoS support for simultaneous transmission of time-critical and conventional data has to be considered. It should be noted that quality of voice communications over the limited bandwidth link depends on coding and modulation methods, performance of the communication link (delay, jitter, loss ratio), traffic structure loading the link but also is sensitive to the network protocols (routing, security, etc.) that would require exchange additional information over the link. Three basic areas of ensuring the QoS for voice communication in IPv6-based military networks with limited bandwidth links have been considered: • use of robust application protocol that provides mechanisms for reliable communication establishing and disconnection as well as priority handling mechanism for voice streams; • efficient use of limited bandwidth that includes application of spectrum-effective vocoders as well as compression