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Military Mobile Ad-Hoc Networking Research Proposal

Performance Metric Evaluation and Commercial Availability

Thomas Moscon 6/15/2014

s1 Introduction...............................................................................................................................3

2 Literature Review..........................................................................................................................4

2.1 Networking Fundamentals.....................................................................................................5

2.1.1 OSI Model......................................................................................................................5

2.2 Ad-hoc Networking................................................................................................................6

2.3 MANETs.................................................................................................................................6

2.4 MANET History......................................................................................................................7

2.5 MANET Achievements...........................................................................................................8

2.6 MANET Challenges.................................................................................................................8

2.7 MANET Performance.............................................................................................................8

2.8 MANET Metric Evaluation......................................................................................................8

2.9 MANET Challenges for Military use.......................................................................................9

2.10 Combat-net Radios................................................................................................................9

2.11 Multi-hop vs. Single-hop........................................................................................................9

2.12 Metrics.................................................................................................................................10

2.13 Commercial-Off-The-Shelf Products....................................................................................10

2.14 COTS Products.....................................................................................................................11

3 Methodology...............................................................................................................................12

3.1 Literature Comparison.........................................................................................................12

3.2 Simulations..........................................................................................................................12

4 Conclusion...................................................................................................................................13

5 Bibliography.................................................................................................................................14

Student address: mosta002@unisa.edu.auStudent ID number: 110043629Award: Bachelor of Information Technology: Network and SecurityProvisional thesis title: Military Mobile Ad-hoc Networking: Performance Metric Evaluation and Commercial AvailabilitySupervisors’ names: Grant WigleyDate of submission: June 15th 2014

Thesis Questions:What are the key metrics in evaluating performance for Military MANETs?

Thesis Sub-QuestionWhat commercially available products suit the needs for a Military based Combat Net Radio MANET?

1 IntroductionThe Defense Science and Technology Organisation (DSTO) are currently undergoing research on Military Mobile Ad-hoc Networks or MANETs for tactical warfare purposes due to the need for an infrastructure-less network communication platform. Currently, the Australian Defence Force (ADF) is using legacy communications hardware with limited bandwidth capabilities and requires a tactical communication solution that allows convergence with speeds as low as sub megabit.

Unlike other countries like the United States, the ADF does not have the resources to deploy a fully converged network infrastructure using satellites and other infrastructure to aid communications within a short timeline on the battlefield. Instead, ‘Combat Net Radios’ and ‘Man packs’ communicating over UHF and VHF frequencies make up the bulk of the network, most of which is either carried by soldiers or mounted in vehicles.

MANETs have been used and developed around the world for different tactical purposes and even spawned from the need for better and more robust tactical networks. The reason Militaries look towards MANETs is that they provide an infrastructure-less, easy and rapidly deployed network with little to no management. This type of solution proves to be invaluable since there isn’t always the time or money to setup network infrastructures on the battlefield for warfare. Instead of routers and switches forwarding packets between layers of the network, all packets are forwarded by the Combat Net Radios and Man Packs, making every soldier and vehicle a router in essence.

However there are still many challenges and unsolved issues relating to MANETs with research and development being an ongoing process, one major issue is the scalability of the network. MANETs have proven to work for small networks or networks with lots of nodes passing information between neighbors or back to a server, but a fully converged brigade in the army with up to 1500 nodes would require an extremely robust system. On top of that, the path of the data through the network can be altered by the design of the Combat Net Radios and how they interface with the other hardware.

For this, MANETs as a solution needs to be analyzed and tested thoroughly in order to produce solid evidence about how to evaluate the performance of a network, and what are the key metrics involved with the overall performance.

2 Literature ReviewThis research is dedicated to the findings on how to evaluate networking performance for Military Mobile Ad-Hoc networks and what commercial-off-the-shelf (COTS) products are available as a solution to this problem. Ad-Hoc networks can be designed for many purposes, but for each different purpose, they are designed differently in order to suit networking needs in a very specific way. The nature of the topic is looking to answer what performance metrics are more important for a Military scenario and how we know those metrics are important.

The basis for this research is on a Military based MANET with up to 1500 nodes/soldiers in at least a 100x100km square block of mountainous and harsh terrain where nodes are constantly moving. These types of network parameters are hard to build a network around, but so far, it is theorized that ad-hoc networking is plausible for this type of tactical warfare.

The research will include looking at previous simulations that have been carried out in the same field to examine how they weigh metrics, evaluation models and frameworks that outline how to generally evaluate MANET performance, and a comparison of commercially available products to determine what type of hardware best suits the needs of a Military MANET and what that hardware does to perform that way.

2.1 Networking FundamentalsGeneric Local Area Network (LAN) or Wide Area Network (WAN) networks designed for office buildings and enterprises usually consist of a hierarchical infrastructure. The most basic of these infrastructures are the three layer hierarchical model, consisting of a core layer providing high speed routing between major regions of the network, the distribution layer which provides most of the routing, security and policies and is usually situated at a branch office connecting to the core and the final layer, the access layer, which connects user devices and servers to the network. This design model is shown in the figure 1 [12].

2.1.1 OSI ModelNot all networks are designed like this, however they all share a model known in networking as the ‘Open Systems Interconnection model’ (OSI Model) seen in Figure 2 [13].

The OSI Model consists of seven layers of networking each responsible for different tasks in data transmission within a network.

Application LayerReserved for application protocols such as HTTP and FTP. It acts as a user-interface for the user responsible for displaying images and data in a human-readable format by communicating with both the presentation and session layer.

Transport LayerThe foundation for TCP, this layers main task is to provide end-to-end communication for applications within or between networks. It provides reliability and flow-control to ensure data is transmitted between hosts without failures, corruption or congestion.

Network LayerResponsible for the routing and forwarding of packets between intermediate routers under protocols such as Internet Protocol (IPv4/6) and Internet Control Message Protocol (ICMP) through the utilization of host addressing to distinguish a packets destination.

Data Link LayerThe layer responsible for Ethernet on Local Area Networks (LAN). This layer provides encapsulation of packets into frames and forwarding data between nodes on the same network with additional functions such as error detection and correction.

Physical LayerOne of the most complex layers, responsible for network hardware transmission technologies of a network. Digital Subscriber Line (DSL), Integrated Services for Digital Network (ISDN) and Wi-Fi are three technologies that reside on the physical layer. Unlike the network layer, the physical layer transmits raw bits instead of packets over physical links such as copper wires or Cat5 cables.

2.2 Ad-hoc NetworkingAd-hoc networks are an infrastructure-less and decentralized approach to network design. The word Ad-hoc meaning ‘for this purpose’ assumes that the network is setup for a specific situation or purpose. In our case, it is for Tactical Warfare. The network is ad-hoc because it does not rely on an underlying infrastructure with managed routers, servers, access points like a traditional Wireless Area Network would. Instead, each and every node in the network acts as a router-device, responsible for forwarding and controlling traffic flow around the network [2].

2.3 MANETsMobile Ad-Hoc Networks were originally developed for tactical network communication due to the dynamic nature of tactical warfare. Military networks have always required a mobile and dynamic design without reliance on a fixed pre-configured infrastructure, not only to ensure rapid deployment, but also to keep costs and complexity to a minimum and autonomy at a maximum.

MANETs create a framework suitable for this type of network design by providing an infrastructure-less network built mainly upon multi-hop peer-to-peer technology that allows nodes to communication over long distances and beyond Line of Sight.

2.4 MANET HistoryThe concept of a military MANET over radio originated from an agency known as the Defense Advanced Research Projects Agency (DARPA). In 1973, the group researched packet-switched radio communication in order to provide mobile network access to computers and terminals within a mobile environment [1]. This research was motivated by the need for tactical communication on the battlefield, and to this day is still being researched for both military and commercial markets.

Packet Radio Networks were the first generation of ad-hoc networks back in 1973. The network consisted of firmware pre-loaded packet radios that had minimal functionality, but was able to communicate to other radios using early radio frequency technology. This technology implemented the physical layer, data link layer and network layer of the OSI model.

The firmware was capable of providing network metrics such as power usage, signal to noise ratio and even had a basic error detection system which forced a retransmission of dropped packets. The routing, although primitive at the time, allowed for rapid and automatic deployment of the network, which was and still is a key factor for tactical communication [6][14].

Second generation ad-hoc networks arrived in the 1980s up to 1993, which were developed and implemented as a part of SURAN (Survivable Adaptive Radio Network Programs). This enhancement improved radio performance by making the networks smaller, cheaper, efficient and more secure [6][14].

A project by the name of GloMo (Global Mobile Information Systems) further enhanced mobile networking by researching self organizing/self healing networks aimed at intelligence information systems for the deployment of forces.

The next development in the second generation of ad hoc networks was NTDR (Near Term Digital Radio Systems), the purpose of which was to provide self-organizing mobile communication between Army Battle Command System automated systems and units at a brigade level and below [6].

Finally third generation MANETs, from the 1990s until present day exploded with the invention of portable laptops and other commercial communication devices based on packet radio systems [6]. MANETS were implemented during this generation and have since been developed for an array of applications.

2.5 MANET AchievementsDespite the Military background of MANETs, in modern day society, MANETs are used for many different applications in order to pass information around users. In a lecture by Kim Smith [3], one particular example of a MANET is Dieselnet, which monitors users who get on and off buses in order to map out where people are coming and going so that the bus system can create better routes.

2.6 MANET ChallengesMANETs propose many challenges due to the way it is inherently designed. In a MANET, all nodes are independent of each other, and all operate in a peer-to-peer mode. This infrastructure-less design adds difficulty to network management, making it challenging to detect and manage faults.

Because nodes in a MANET will always be moving, the topology of the network will be dynamic, causing frequent route changes which can result in packet losses.

2.7 MANET PerformanceThe routing performance for MANETs differs for each routing protocol. For example, a routing protocol such as Dynamic Source Routing (DSR) may incur less overhead than a protocol such as Optimised Link State Routing Protocol (OLSR) due to the fact that it will transmit traffic data only when there is data to be sent, where as OLSR floods the network with control and traffic data aimed at keeping the routing tables updated as much as possible [7][17][26].

However this doesn’t always mean that certain routing protocols are better than others, they may perform better in certain scenarios and for different purposes.

2.8 MANET Metric EvaluationIn an RFC written by S. Corson and J Macker [4], the authors distinguish a difference in metrics between a routing protocol and the network context itself. To a further degree, it is also stated that separate qualitative and quantitative metrics are evaluated for a network protocol.

Qualitative metrics explained were sleep and security, etc., where as quantitative metrics include throughput and delay, efficiency which looks at data/control bits sent and received, and route acquisition time. Finally, metrics that are important to a routing protocols overall context are network size, network connectivity, traffic patterns, mobility, link capacity, and topological rate of change and others.

There are two main ways to evaluate the performance of a MANET. The first approach uses measurement techniques in order to evaluate a real prototype network, usually a test bed, which is important in realising constraints and issues with a network that may not show up in simulations. One of the largest testbeds with up to 30 nodes is the Uppsala University APE testbed which revealed problems relating to different transmission ranges for control and data frames, a problem known as the ‘communication gray zones’ [2].

The other approach to evaluating the performance of a MANET is via a simulation model, usually simulated on either OPNET or NS-2. Many simulation models have been constructed in order to test the performance of a MANET [8][9][10][11][23][24][25], but it is important to note that a simulations

do not accurately represent the actual performance of an entire network, rather they aid us in answering specific questions about the network or help us to diagnose imperatives in the design. Mobility models in particular aid in discovering the effects of mobility on a network, though limited, the results these types of models can still provide useful and intelligence evidence.

Lastly, using simulations as a method of evaluating a large network can sometimes be deceiving and a large understanding of networking is required in order to evaluate the data correctly. Many researchers delve into the credibility of simulations for MANETs because of this issue [15].

2.9 MANET Challenges for Military useMany popular MANET algorithms that were designed were done so for small fixed networks, however a lot of tactical MANETs are designed with thousands of nodes in mind which makes scalability still an issue that has unresolved challenges that range from configuration management, security, interoperability, addressing and most of all routing.

In the Military, a term coined SWAP (Size, Weight and Power) is an extremely important aspect for operating in tactical warfare and adds an extra budget for the types of physical networking devices plausible out on the field [5][16]. Reducing the size, weight and power of each device on a soldier is crucial for a more mobile and logistical mission. However, this limits the amount of processing power allowed on each node which in turn limits the effectiveness of the MANET since every node must act as a router as well as an end-user device. This proposes a tradeoff between efficiency and reliability.

2.10 Combat-net RadiosRadio’s used for tactical purposes are generally known as ‘Combat-net Radios’ (CNRs). These radios are primarily push-to-talk handheld devices that utilize certain waveforms in order to transmit and receive radio signals. CNRs most popularly operate on the Very High Frequency (VHF band) and the Ultra High Frequency (UHF) band, meaning they only transmit radio signals between the frequencies of 30-300 MHz and 300-3,000 MHz respectively.

There are many factors that determine the performance of a CNR. These include power, frequency, line of sight and environmental interference. For the factors we as humans can control, the more power used, the greater the range of transmission, but most radios reach up to 10 watts.

2.11 Multi-hop vs. Single-hopNetworks can be also be defined into single-hop or multi-hop. Single-hop refers to a network where there is only one hop between the source and destination, usually a default gateway or router. Multi-hop networks are used when there is no default router available, much like a traditional MANET where every node acts as a router to forward data around the network.

This approach is usually preferable for rapid deployment in hard-to-wire areas making it ideal for tactical MANETs as it is impossible for the military to wire a network backbone in every location of operation. It is also required in order to extend coverage of the network through multi-hop forwarding.

2.12 MetricsIn networking, there are many parameters that can affect the performance of a network, which are known as metrics. Some metrics are more important to analyse than others when diagnosing issues or slowness within a network, making it a network administrator’s job to know which metrics are important for what type of application or network usage. When diagnosing the performance of a network, network tools are commonly used to display metrics between devices and the overall network, but can also be output from simulations in order to analyse the performance of a network in the scenario being simulated.

In the simplest cases, downloading large files from somewhere is a scenario in which a large throughput is desired, making the speed in which the files are received quicker. Alternatively, playing a video game over the internet requires extremely low latency, where no delays are present and the actions/data sent by the client to the server and vice versa and almost synced. With a high latency, lag would occur and the game would become unplayable.

OPNET, one of the most common networking simulators, is able to output a variety of metrics including throughput, utilization, number of hops per route, route discovery time, average power and retransmission attempts. Some of these metrics may affect the performance of the network more, and others may be barely useful at all. These types of simulators can tell us valuable information about how a network would perform in a certain scenario, but require a decent knowledge of the network being simulated in order to properly diagnose the results to make decisions and answer questions based upon them.

2.13 Commercial-Off-The-Shelf ProductsMany Governments purchase what is known as Commercial-off-the-shelf products, meaning products that are publicly available which can be bought under a government contract. The advantage of this purchase is the reduction of development, maintenance time and a saving on cost. Notably, COTS products can also provide a standardized approach instead of a custom in-house development approach which would add a significant cost to time and money. Standardization also means that there is already more than enough documentation and support for the product.

It is believed that COTS products are of a higher quality than custom developed products due to the competitive nature of the marketplace, however true, it may lead to some security issues with the purchase. Notably in IT especially, COTS products can pose security risks due to the public nature of the product and the integration with other products. Although this is more prominent for software products than hardware it is still worth noting that COTS products have been the cause of safety concerns for the Military in the past.

2.14 COTS ProductsFew companies design commercial products for MANET solutions, as they are not a popular choice for industry networks, however there is still Research and Development carried out for Tactical MANETs, below are a few examples of some MANET technologies.

Cisco- Radio Aware Routing for Mobile Networking

Bluetronix (Bluestar)- R&D for Government Military MANET solutions- SWARM Intelligent Routing

Trellisware - Military MANET development, Robust Hardware- Converged physical/network layer waveform- Tactical Scalable MANET (TSM) Waveform

Harris- Another Military hardware provider- Joint Tactical Radio System (JTRS) certified products

3 Methodology

3.1 Literature ComparisonThe first pool of results will aim to compare the simulations and data gathered from existing public papers to get a rough overview of the most important and key metrics involved with the performance of MANETs. Only quantitative data will be collected as qualitative data is not relevant in a Military scenario. The only significant qualitative metric would be security which is a non-issue for the military.

Metric rankings will be collected from at least 10 different sources, the sources being mostly conference papers, journal articles and published books. Points will be given to each metric based on their effect on the performance for each scenario tested.

As this method is unreliable in giving a sure answer to the question with the possibility of mixed results and a mixture of different test scenarios, it is only done for interests sake, and to see if any patterns emerge that may provide me with useful information.

3.2 SimulationsSimulations will be conducted using one of the two popular network simulators NS-2 or OPNET. The conditions for the simulations will be 1 test with a chosen best routing algorithm. First, a base simulation will be conducted with 1500 nodes in order to achieve a decent network benchmark. From there, each different network metric will be purposefully interfered with in order to observe the effect that metric has on the performance of the network.

The effect on the performance of the network will be measured by sending the same artificial traffic around the network for each test, and analyzing performance metrics such as packet loss, speed of packets, total control/data traffic sent/received, etc.

Once all the simulations have been carried out as carefully as possible, the data gathered will hopefully show which metric affects performance the most, and which one affects it the least. From this, graphs and tables can be deduced that show each metrics affect on the performance of the network and if there is enough convincing evidence, a ranking table will be formulated.

4 ConclusionIt is obvious that MANETs have potential as a solution for tactical communications but not without many issues and challenges to overcome such as scalability, network management, terrain interference, bandwidth and hardware limitations, and overall performance.

However there is no doubt a need for this type of network in the military due to the lack of possible ways to deploy networking infrastructure on the fly. Utilizing MANETs means cheap and rapid deployment for the army in the easiest way possible.

Using Commercial-off-the-shelf products is an obvious choice for governments as it cuts cost, development and maintenance time. As well it provides a more standardized approach allowing for better support for the product and a better performance guarantee.

Much of the research done for MANETs however doesn’t explain exactly how to measure its performance. Most of this is done by network tools through the use of algorithms, but a lot of those tools were intended to measure the performance of generic LAN scenarios and not MANET scenarios where mobility plays an overarching factor on the performance, as well as the conditions that are added due to a military setting.

This advocates the question “What are the key metrics in evaluating performance for Military MANETs”.

5 Bibliography

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