Internet routing paths stability model and relation to forwarding paths

Analysis of real datasets to characterize the local stability properties of the Internet routing paths suggests that extending the route selection criteria to account for such property would not increase the routing path length. Nevertheless, even if selecting a more stable routing path could be considered as valuable from a routing perspective, it does not necessarily imply that the associated forwarding path would be more stable. Hence, if the dynamics of the Internet routing and forwarding system show different properties, then one can not straightforwardly derive the one from the other. If this assumption is verified, then the relationship between the stability of the forwarding path (followed by the traffic) and the corresponding routing path as selected by the path-vector routing algorithm requires further characterization. For this purpose, we locally relate, i.e., at the router level, the stability properties of routing path with the corresponding forwarding path. The proposed stability model and measurement results verify this assumption and show that, although the main cause of instability results from the forwarding plane, a second order effect relates forwarding and routing path instability events. This observation provides the first indication that differential stability can safely be taken into account as part of the route selection process

Density-Dependent Analysis of Nonequilibrium Paths Improves Free Energy Estimates II. A Feynman-Kac Formalism

The nonequilibrium fluctuation theorems have paved the way for estimating equilibrium thermodynamic properties, such as free energy differences, using trajectories from driven nonequilibrium processes. While many statistical estimators may be derived from these identities, some are more efficient than others. It has recently been suggested that trajectories sampled using a particular time-dependent protocol for perturbing the Hamiltonian may be analyzed with another one. Choosing an analysis protocol based on the nonequilibrium density was empirically demonstrated to reduce the variance and bias of free energy estimates. Here, we present an alternate mathematical formalism for protocol postprocessing based on the Feynmac-Kac theorem. The estimator that results from this formalism is demonstrated on a few low-dimensional model systems. It is found to have reduced bias compared to both the standard form of Jarzynski's equality and the previous protocol postprocessing formalism.Comment: 21 pages, 5 figure

An Alloy Verification Model for Consensus-Based Auction Protocols

Max Consensus-based Auction (MCA) protocols are an elegant approach to establish conflict-free distributed allocations in a wide range of network utility maximization problems. A set of agents independently bid on a set of items, and exchange their bids with their first hop-neighbors for a distributed (max-consensus) winner determination. The use of MCA protocols was proposed, $e.g.$, to solve the task allocation problem for a fleet of unmanned aerial vehicles, in smart grids, or in distributed virtual network management applications. Misconfigured or malicious agents participating in a MCA, or an incorrect instantiation of policies can lead to oscillations of the protocol, causing, $e.g.$, Service Level Agreement (SLA) violations. In this paper, we propose a formal, machine-readable, Max-Consensus Auction model, encoded in the Alloy lightweight modeling language. The model consists of a network of agents applying the MCA mechanisms, instantiated with potentially different policies, and a set of predicates to analyze its convergence properties. We were able to verify that MCA is not resilient against rebidding attacks, and that the protocol fails (to achieve a conflict-free resource allocation) for some specific combinations of policies. Our model can be used to verify, with a "push-button" analysis, the convergence of the MCA mechanism to a conflict-free allocation of a wide range of policy instantiations

Optimization flow control -- I: Basic algorithm and convergence

We propose an optimization approach to flow control where the objective is to maximize the aggregate source utility over their transmission rates. We view network links and sources as processors of a distributed computation system to solve the dual problem using a gradient projection algorithm. In this system, sources select transmission rates that maximize their own benefits, utility minus bandwidth cost, and network links adjust bandwidth prices to coordinate the sources' decisions. We allow feedback delays to be different, substantial, and time varying, and links and sources to update at different times and with different frequencies. We provide asynchronous distributed algorithms and prove their convergence in a static environment. We present measurements obtained from a preliminary prototype to illustrate the convergence of the algorithm in a slowly time-varying environment. We discuss its fairness property

ANALISIS PERFORMANSI ROUTING PROTOCOL UNTUK KOMUNIKASI DATA SIMPLE HIGHWAY MOBILITY MODEL (SHWM) PADA JARINGAN 802.11p

ABSTRAKSI: Vehicular Ad Hoc Network (VANET) adalah jaringan yang terdiri dari sekumpulan wireless mobile node yang saling berkomunikasi tanpa infrastruktur yang tetap. Mobilitas node pada VANET sangat tinggi dan ini menyebabkan perubahan dari topologi jaringan VANET yang sangat sering. Berdasarkan kondisi jaringan yang berubah-ubah tersebut maka proses pencarian jalur yang tepat merupakan salah satu hal yang menjadi masalah dalam VANET. Salah satu model arsitektur VANET yang membutuhkan proses pencarian jalur yang tepat yaitu Simple Highway Mobility Model (SHWM). SHWM merupakan model VANET yang daerahnya memiliki keterbatasan dalam ketersediaan device RSU. Komunikasi data pada SHWM dapat dilakukan dengan cluster ataupun tanpa cluster. Pada penelitian ini, SHWM tanpa cluster yang akan disimulasi dan akan dianalisis hasilnya.Ada 2 jenis routing protocol, yaitu reactive dan proaktif. Destination Sequence Distance Vector (DSDV) dan Ad Hoc on Demand Distance Vector (AODV) merupakan dua routing protocol yang sering direkomendasikan untuk digunakan pada jaringan VANET. DSDV merupakan routing protocol proaktif, sedangkan AODV merupakan routing protocol reactive. Kedua routing protocol ini akan disimulasikan dalam kondisi jaringan VANET dengan node 10, 20, dan 40 serta kecepatan node 10m/s, 20m/s, dan 25m/s dengan menggunakan network simulator 2 (NS-2).Evaluasi kinerja dari routing protocol DSDV dan AODV tersebut ditinjau dari parameter : routing overhead, normalized routing load, packet delivery ratio, packet loss ratio, dan convergence time. Namun, parameter packet delivery ratio dan packet loss ratio yang sangat berpengaruh pada hasil simulasi, sebab parameter ini mengindikasikan keberhasilan paket data yang dikirim dari node sumber ke node tujuan. Hasil dari simulasi ini kemudian dianalisis dan dihasilkan bahwa AODV lebih baik untuk kondisi jaringan yang tingkat mobilitasnya tinggi dan jumlah nodenya banyak. Pada skenario jumlah node 10 dengan kecepatan 10m/s didapat bahwa nilai packet delivery ratio AODV 94,9071% sedangkan packet delivery ratio DSDV 77.0833%, dan untuk parameter packet loss ratio nilai AODV sebesar 5,09294% sedangkan DSDV sebesar 22.9167%.Kata Kunci : VANET, SHWM, reactive, proaktif, routing protocol, DSDV, AODV, routing overhead, normalized routing load, packet delivery ratio, packet loss ratio, convergence time, dan NS-2ABSTRACT: Vehicular Ad Hoc Network (VANET) is a network that consists of a set of wireless mobile nodes that communicate with each other without a fixed infrastructure. Node mobility in VANET is very high and this causes a change of network topology VANET very often. Based on network conditions are changing the process of finding the right path is one that is at issue in the VANET. One of the VANET architecture model that requires the process of finding the right lane is Simple Highway Mobility Model (SHWM). SHWM is a regional model VANET which has limitations in the availability of RSU device. SHWM data communications can be performed on the cluster or no cluster. And for that, the area is also necessary process of finding the right path. In this research, SHWM without the cluster that will be simulated and analyzed the results.There are two types of routing protocols, namely reactive and proactive. Destination Sequence Distance Vector (DSDV) and Ad Hoc on Demand Distance Vector (AODV) routing protocol is the two are often recommended for use on the VANET. DSDV is a proactive routing protocol, while AODV is a reactive routing protocol. Both of these routing protocols will be simulated in a state of VANET networks with nodes 10, 20, and 40 as well as node speed of 10m / s, 20m / s and 25m / s by using the network simulator 2 (NS-2).Evaluate the performance of DSDV and AODV routing protocol is in terms of parameters: the routing overhead, normalized routing load, packet delivery ratio, packet loss ratio, and the convergence time. However, the parameter packet delivery ratio and packet loss ratio is very influential on the results of the simulation, because this parameter indicates the success of data packets sent from source node to destination node. The results of simulations are then analyzed and produced that AODV is better to network conditions and the high mobility rate nodenya much. In this scenario the number of node 10 with a speed of 10m / s is found that the packet delivery ratio of AODV 94.9071% while the packet delivery ratio of DSDV 77.0833%, and packet loss ratio for the parameter values of 5.09294%, while AODV DSDV of 22.9167%.Keyword: VANET, SHWM, reactive, proactive, routing protocols, DSDV, AODV, routing overhead, normalized routing load, packet delivery ratio, packet loss ratio, convergence time, and NS-