Spray Router with Node Location Dependent Remaining-TTL Message Scheduling in DTNs

Delay and disruption tolerant networks (DTNs) adopt the store-carry-and-forward paradigm. Each node stores messages in a buffer storage and waits for either an appropriate forwarding opportunity or the message\u27s expiration time, i.e., its time-to-live (TTL). There are two key issues that influence the performance of DTN routing: the forwarding policy that determines whether a message should be forwarded to an encountered node, and the buffer management policy that determines which message should be sent from the queue (i.e., message scheduling) and which message should be dropped when the buffer storage is full. This paper proposes a DTN routing protocol, called spray-and hop-distance-based with remaining-TTL consideration (SNHD-TTL) which integrates three features: (1) binary spray; (2) hop-distance-based forwarding; and (3) node location dependent remaining-TTL message scheduling. The aim is to better deliver messages which are highly congested especially in the “island scenario.” We evaluate it by simulation-based comparison with other popular protocols, namely Epidemic as a baseline and PRoPHETv2 that performs well according to our previous study. Our simulation results show that SNHD-TTL is able to outperform other routing protocols, significantly reduce overhead, and at the same time, increase the total size of delivered messages.Special Issue of Applications and the Internet in Conjunction with Main Topics of COMPSAC 201

TCP with Network Coding Performance Under Packet Reordering

The adverse impact of packet reordering besides packet loss is significant on the goodput performance of TCP (Transmission Control Protocol), a dominant protocol for reliable and connection-oriented transmission. With the primary purpose of improving the TCP goodput in lossy networks, the Network Coding technique was introduced. TCP/NC (TCP with Network Coding) is a promising approach which can recover lost packets without retransmission. However, the packet reordering has not been considered, and no study on that issue is found for TCP/NC. Therefore, in this paper, we investigate the goodput performance degradation due to the out-of-order reception of data or acknowledgment packets and propose a new scheme for TCP/NC to estimate and adapt to the packet reordering. The results of our simulation on ns-3 (Network Simulation 3) suggest that the proposed scheme can maintain the TCP goodput well in a wide range of packet reordering environments compared to TCP NewReno as well as TCP/NC.International Conference on Emerging Internetworking, Data & Web Technologies (EIDWT 2019), 26-28 February, 2019, Fujairah Campus, United Arab Emirate

A Design and Prototyping of In-Network Processing Platform to Enable Adaptive Network Services

The explosive growth of the usage along with a greater diversification of communication technologies and applications imposes the Internet to manage further scalability and diversity, requiring more adaptive and flexible sharing schemes of network resources. Especially when a number of large-scale distributed applications concurrently share the resource, efficacy of comprehensive usage of network, computation, and storage resources is needed from the viewpoint of information processing performance. Therefore, a reconsideration of the coordination and partitioning of functions between networks (providers) and applications (users) has become a recent research topic. In this paper, we first address the need and discuss the feasibility of adaptive network services by introducing special processing nodes inside the network. Then, a design and an implementation of an advanced relay node platform are presented, by which we can easily prototype and test a variety of advanced in-network processing on Linux and off-the-shelf PCs. A key feature of the proposed platform is that integration between kernel and userland spaces enables to easily and quickly develop various advanced relay processing. Finally, on the top of the advanced relay node platform, we implement and test an adaptive packet compression scheme that we previously proposed. The experimental results show the feasibility of both the developed platform and the proposed adaptive packet compression

Inferring Traffic Flow Characteristics from Aggregated-flow Measurement

In the Internet, a statistical perspective of global traffic flows has been considered as an important key to network operations and management. Nonetheless, it is expensive or sometime difficult to measure statistics of each flow directly. Therefore, it is of practical importance to infer unobservable statistical characteristics of individual flows from characteristics of the aggregated-flows, which are easily observed at some links (e.g., router interfaces) in the network. In this paper, we propose a new approach to such inference problems based on finding an inverse function from (observable) probabilities of some states on aggregated-flows to (unobservable) probabilities of some states on flows on a discrete state model, and provide a method inferring arrival rate statistics of individual flows (the OD traffic matrix inference). Our method is applicable to cases not covered by the existing normal-based methods for the OD traffic matrix inference. We also show simulation results on several flow topologies, which indicate potential of our approach

One-to-many file transfer using multipath multicast with gossiping

With the recent progress of cloud and distributed computing technologies, data migration and replication among distributed data centers grows rapidly. To manage a simplified scenario that a single sender sends a large-sized file to multiple recipients, i.e., one-to-many file transfer, on a network with full-duplex links, we are developing the Multipath-Multicast (MPMC) file transfer. A file is appropriately divided into equally-sized blocks; different blocks are concurrently transmitted to the same recipient on multiple paths; while the same block is concurrently transmitted to multiple recipients by multicast, aiming at shorter reception completion times of all recipients. However, on large-scale complex network topologies, it is not easy to find a good block transfer schedule, i.e., that realizes the reception completion times of most recipients close to their lower-bounds in MPMC. In this report, therefore, a gossiping approach to allow block transfer among recipients is introduced into MPMC and evaluated through simulation on two real backbone topologies. Since unused capacities of links in the original basic MPMC can be utilized in the MPMC with gossiping, a good schedule can be found more easily compared with the basic MPMC even with the same simple greedy block allocation.The 4th IEEE International Conference on Network Softwarization (NetSoft 2018) , June 25-29, 2018, Montreal, Canada

TCP network coding with adapting parameters for bursty and time-varying loss

The Transmission Control Protocol (TCP) with Network Coding (TCP/NC) was proposed to introduce packet loss recovery ability at the sink without TCP retransmission, which is realized by proactively sending redundant combination packets encoded at the source. Although TCP/NC is expected to mitigate the goodput degradation of TCP over lossy networks, the original TCP/NC does not work well in burst loss and time-varying channels. No apparent scheme was provided to decide and change the network coding-related parameters (NC parameters) to suit the diverse and changeable loss conditions. In this paper, a solution to support TCP/NC in adapting to mentioned conditions is proposed, called TCP/NC with Loss Rate and Loss Burstiness Estimation (TCP/NCwLRLBE). Both the packet loss rate and burstiness are estimated by observing transmitted packets to adapt to burst loss channels. Appropriate NC parameters are calculated from the estimated probability of successful recoverable transmission based on a mathematical model of packet losses. Moreover, a new mechanism for coding window handling is developed to update NC parameters in the coding system promptly. The proposed scheme is implemented and validated in Network Simulator 3 with two different types of burst loss model. The results suggest the potential of TCP/NCwLRLBE to mitigate the TCP goodput degradation in both the random loss and burst loss channels with the time-varying conditions

Accurate OD Traffic Matrix Estimation Based on Resampling of Observed Flow Data

It is important to observe the statistical characteristics of global flows, which are defined as series of packets between networks, for the management and operation of the Internet. However, because the Internet is a diverse and large-scale system organized by multiple distributed authorities, it is not practical (sometimes impossible) to directly measure the precise statistical characteristics of global flows. In this paper, we consider the problem of estimating the traffic rate of every unobservable global flow between corresponding origin-destination (OD) pair (hereafter referred to as “individual-flows”) based on the measured data of aggregated traffic rates of individual flows (hereafter referred to as “aggregated-flows”), which can be easily measured at certain links (e.g., router interfaces) in a network. In order to solve the OD traffic matrix estimation problem, the prior method uses an inverse function mapping from the probability distributions of the traffic rate of aggregated-flows to those of individual-flows. However, because this inverse function method is executed recursively, the accuracy of estimation is heavily affected by the initial values of recursion and variation of the measurement data. In order to solve this issue and improve estimation accuracy, we propose a method based on a resampling of measurement data to obtain a set of solution candidates for OD traffic matrix estimation. The results of performance evaluations using a real traffic trace demonstrate that the proposed method achieves better estimation accuracy than the prior method.Asia-Pacific Signal and Information Processing Association Annual Summit and Conference 2018 (APSIPA ASC 2018), 12-15 November 2018, Honolulu, Hawaii, US

Cognitive Radio-Aware Transport Protocol for Mobile Ad Hoc Networks

With the proliferation of new wireless service, scarce wireless resources is expected to become a critical issue. For this reason, cognitive radio mobile ad hoc networks (CogMANET) are being developed as a promising solution to this problem. However, in CogMANET, channel switching is inherently necessary whenever a primary user with a license appears on the channel. Allowing secondary users to choose an available channel from among a wide spectrum range thus enables reliable communication in this context, but communication characteristics such as bottleneck bandwidth and RTT will change with channel switch. In response to this change, TCP has to adaptively update its congestion window (cwnd) to make an efficient use of the available resources. For this purpose, TCP CRAHN was proposed for CogMANET. In this paper, TCP CRAHN is first evaluated in cases where bottleneck bandwidth and RTT drastically change. Based on these results, TCP CoBA is proposed to further improve the throughput of the above use cases. TCP CoBA updates the cwnd based upon the available buffer space in the relay node upon channel switch, as well as other communication characteristics. Through simulations, we show that compared with TCP CRAHN, TCP CoBA improves the throughput by up to 200 percent