Improving ns-3 Emulation Performance for Fast Prototyping of Network Protocols

O desenvolvimento de novos protocolos de comunicação começa tipicamente comrecurso a um simulador de redes, como o ns-3, onde as variáveis que influenciamo cenário da rede são facilmente controladas para criar condições de testeespecíficas e reproduzíveis. Os resultados da simulação são então analisados eusados para ajustar e melhorar o protocolo. Posteriormente a esta fase, oprotocolo deve também ser testado em ambiente real de forma a serem obtidosresultados mais precisos e credíveis. Para isso, o código anteriormentedesenvolvido para simulação tem que ser reimplementado num sistema real. Esteprocesso conduz a um aumento do tempo de desenvolvimento e da hipótese deintrodução de erros na implementação.A prototipagem rápida é um processo de desenvolvimento de protocolos que tentaresolver este problema através da reutilização do código de simulação ns-3 emsistemas reais. Esta reutilização é possível porque o ns-3 disponibilizadafuncionalidades de emulação que permitem que os nós simulados comuniquem com oexterior da simulação. No entanto, a emulação degrada o desempenho dos nós o quelimita a quantidade de tráfego de rede que pode ser processada.Neste trabalho, propomos uma abordagem para reduzir os problemas de desempenhoassociados à prototipagem rápida que consiste em migrar as operações do plano dedados para fora do ns-3. Há dois planos de operações num nó de rede: controlo edados. O plano de controlo é responsável por descobrir e manter as rotas de redee assegurar a conetividade. O plano de dados usa a informação das rotas geradapelo plano de controlo para encaminhar os pacotes de rede. Numa rede típica, amaioria do tráfego corresponde a dados. Mover o plano de dados para fora do ns-3pode, então, reduzir o custo associado ao processamento deste tipo de tráfego.De forma a validar a solução proposta, estendemos os protocolos WirelessMetropolitan Routing Protocol (WMRP) e Optimized Link State Routing (OLSR) parausarem a arquitetura desenvolvida, testámos o seu desempenho em ambientes reaise verificámos a quantidade de código que foi reutilizada entre a simulação e osistema real.The development of new protocols for communication systems usually starts in anetwork simulator, such as ns-3, where the variables that influence the networkscenario can be easily controlled to create specific and reproducible testconditions. The results of such simulations are then analyzed and used to tweakand improve the protocol. After this phase, the protocol must also be tested ina real environment to obtain more accurate and credible results. To do this, thesimulation code must be ported to a real system. This process of porting codefrom the simulation to the implementation of the protocol leads to an increasein development time and in the chance of introducing errors.Fast prototyping is a protocol development process that attempts to solve thisproblem by reusing ns-3 simulation code for the implementation. This is possiblebecause ns-3 provides emulation capabilities that allow nodes inside thesimulator to communicate with those outside through an emulated network device.The problem with this approach is that emulation introduces overhead to packetprocessing which degrades the node's performance limiting the amount of networktraffic that can be processed.We propose an approach to reduce the performance problem associated with fastprototyping that consists in migrating the data plane operations processing tooutside of ns-3. In a network node, there are two planes of operation: controland data. The control plane is responsible for discovering and maintainingnetwork routes and ensuring connectivity. The data plane uses the routinginformation generated by the control plane to forward network packets. In a welldesigned network, most of the traffic corresponds to data. By moving the dataplane operations outside of ns-3 the overhead associated with this kind oftraffic is greatly reduced.To validate our proposed solution, we extended the Wireless MetropolitanRouting Protocol (WMRP) and Optimized Link State Routing (OLSR) protocols to usethe developed architecture, tested their performance in real environments andverified the amount of code reuse between the simulator and the real system

Faithful reproduction of network experiments

The proliferation of cloud computing has compelled the research community to rethink fundamental aspects of network systems and architectures. However, the tools commonly used to evaluate new ideas have not kept abreast of the latest developments. Common simulation and emulation frameworks fail to provide scalability, fidelity, reproducibility and execute unmodified code, all at the same time. We present SELENA, a Xen-based network emulation framework that offers fully reproducible experiments via its automation interface and supports the use of unmodified guest operating systems. This allows out-of-the-box compatibility with common applications and OS components, such as network stacks and filesystems. In order to faithfully emulate faster and larger networks, SELENA adopts the technique of time-dilation and transparently slows down the passage of time for guest operating systems. This technique effectively virtualizes the availability of host’s hardware resources and allows the replication of scenarios with increased I/O and computational demands. Users can directly control the tradeoff between fidelity and running-times via intuitive tuning knobs. We evaluate the ability of SELENA to faithfully replicate the behaviour of real systems and compare it against existing popular experimentation platforms. Our results suggest that SELENA can accurately model networks with aggregate link speeds of 44 Gbps or more, while improving by four times the execution time in comparison to ns3 and exhibits near-linear scaling properties.This is the author accepted manuscript. The final version is available from ACM via http://dx.doi.org/10.1145/2658260.265827

Scalable Real-time Emulation of 5G Networks with Simu5G

Real-time emulation of 5G networks is highly beneficial for several purposes, such as prototyping or performance evaluation of distributed applications meant to run on 5G networks, research demonstration, evaluation of other technologies (e.g., Multi-access Edge Computing) meant to interoperate with 5G access. In this work, we describe how to use Simu5G, a new end-to-end simulator of 5G networks based on OMNeT++, as a real-time emulator. We describe in detail the modeling choices that allow emulation to scale up without compromising accuracy. We present a thorough evaluation of the Simu5G’s emulation capabilities, showing that networks with hundreds of simulated users and tens of cells can be emulated on a single desktop machine

A Comprehensive Survey of In-Band Control in SDN: Challenges and Opportunities

Software-Defined Networking (SDN) is a thriving networking architecture that has gained popularity in recent years, particularly as an enabling technology to foster paradigms like edge computing. SDN separates the control and data planes, which are later on synchronised via a control protocol such as OpenFlow. In-band control is a type of SDN control plane deployment in which the control and data planes share the same physical network. It poses several challenges, such as security vulnerabilities, network congestion, or data loss. Nevertheless, despite these challenges, in-band control also presents significant opportunities, including improved network flexibility and programmability, reduced costs, and increased reliability. Benefiting from the previous advantages, diverse in-band control designs exist in the literature, with the objective of improving the operation of SDN networks. This paper surveys the different approaches that have been proposed so far towards the advance in in-band SDN control, based on four main categories: automatic routing, fast failure recovery, network bootstrapping, and distributed control. Across these categories, detailed summary tables and comparisons are presented, followed by a discussion on current trends a challenges in the field. Our conclusion is that the use of in-band control in SDN networks is expected to drive innovation and growth in the networking industry, but efforts for holistic and full-fledged proposals are still needed

The state of peer-to-peer network simulators

Networking research often relies on simulation in order to test and evaluate new ideas. An important requirement of this process is that results must be reproducible so that other researchers can replicate, validate and extend existing work. We look at the landscape of simulators for research in peer-to-peer (P2P) networks by conducting a survey of a combined total of over 280 papers from before and after 2007 (the year of the last survey in this area), and comment on the large quantity of research using bespoke, closed-source simulators. We propose a set of criteria that P2P simulators should meet, and poll the P2P research community for their agreement. We aim to drive the community towards performing their experiments on simulators that allow for others to validate their results

A simulation environment for software defined wireless networks with legacy devices

The adoption of Software Defined Networks (SDNs) in a Mobile ad-hoc network (MANET) could present several benefits, such as adaptability and performance increase. However, to assess this possibility, a simulation tool may be necessary to test new protocols and solutions in a large combination of scenarios and traffic patterns, without the need of real equipment. Unfortunately, few tools are available for wireless SDNs, and none have the ability to also support MANETs with multiple radio access technologies. While NS-3 has the ability to simulate heterogeneous MANETs, it does not support wireless OpenFlow capable devices or wireless OpenFlow channels. In this work we present a simulation environment that, besides creating an ad-hoc data plane, enables the possibility of creating wireless hybrid SDN devices capable of connecting to legacy devices, alongside with an LTE OpenFlow channel connected to an external SDN Controller (RYU). Results show that the simulation environment supports large networks with both legacy and SDN devices, although these will bear an effective running time higher than their simulation time. Moreover, when comparing to an OLSR-only network, the proposed network (with a basic path search metric) has the same or higher performance.info:eu-repo/semantics/publishedVersio