Packet Forwarding Path Research Articles

A Negotiation-Based Scheme for Interconnecting Heterogeneous Networks With Enhanced Services

Although the TCP/IP protocols have made great contributions to the development of the Internet, there is a consensus that the Internet needs improvement to solve the address space exhausted, content-oriented service, and so on. The academic community has proposed lots of valuable but heterogeneous network protocols, which provide better network services but split the Internet. To connect these heterogeneous networks, many middleboxes (e.g.,NAT and Tunnel) are deployed on the Internet, but these middleboxes mask the communication peers and shield various network services that are provided by these heterogeneous networks. In this article, we propose the HNN (heterogeneous networks negotiation), which provides transparent end-to-end communication and connects heterogeneous networks stateless in the data plane. What's more, HNN enables the host to perceive the available network service provided by heterogeneous networks and helps the host structure appropriate packet header and packet forwarding path to take advantage of these heterogeneous network services. We implement and evaluate an HNN prototype with commodity Barefoot Tofino programmable switch S9180-32X. The evaluation results demonstrate that HNN introduces little processing time overhead (no more than 3%) compared to well-known heterogeneous connectivity techniques (i.e.,NAT and Tunnel) and allows hosts to utilize heterogeneous network services.

LRVP: Lightweight Real-Time Verification of Intradomain Forwarding Paths

The correctness of user traffic forwarding paths is an important goal of trusted transmission. Many network security issues are related to it, i.e., denial-of-service attacks, route hijacking, etc. The current path-aware network architecture can effectively overcome this issue through path verification. At present, the main problems of path verification are high communication and high computation overhead. To this aim, this article proposes a lightweight real-time verification mechanism of intradomain forwarding paths in autonomous systems to achieve a path verification architecture with no communication overhead and low computing overhead. The problem situation is that a packet finally reaches the destination, but its forwarding path is inconsistent with the expected path. The expected path refers to the packet forwarding path determined by the interior gateway protocols. If the actual forwarding path is different from the expected one, it is regarded as an incorrect forwarding path. This article focuses on the most typical intradomain routing environment. A few routers are set as the verification routers to block the traffic with incorrect forwarding paths and raise alerts. Experiments prove that this article effectively solves the problem of path verification and the problem of high communication and computing overhead.

Constant-Size Credential-Based Packet Forwarding Verification in SDN

The emerging software-defined networking (SDN) technology lacks tools to proactively ensure that policies will be followed or to inspect the behavior of the network. The network is vulnerable to sophisticated attacks against packets, such as alteration, injection, dropping, and hijacking attacks. Accurate and efficient network packet forwarding verification is a critical issue to ensure the correctness of packet forwarding when confronting with malicious attacks, while most of the existing packet forwarding verification solutions were implemented by inserting linear-scale cryptographic tags that increased with path length, which introduced significant communication overhead. In this paper, we propose a constant-size credential based packet forwarding verification mechanism in SDN. In the scheme, the ingress switch of a flow embeds a tag credential of constant-size which is independent of the packet forwarding path, each downstream switch verifies packets basing on the constant-size credential, and the controller periodically acquires node forwarding statistics along the path and localizes anomaly. The header space communication overhead of the proposed scheme is less than existing linear-scale mechanisms. We further prototype and evaluate the proposed scheme. Experiments demonstrate that the scheme achieves efficient forwarding and effective anomaly localization with less than 11% of additional forwarding delays and no more than 10% of throughput degradation.

Event Driven Duty Cycling with Reinforcement Learning and Monte Carlo Technique for Wireless Network

Reducing transmission delay and maximizing the network lifetime are important issues for wireless sensor networks (WSN). The existing approaches commonly let the nodes periodically sleep to minimize energy consumption, which adversely increases packet forwarding latency. In this study, a novel scheme is proposed, which effectively determines the duty cycle of the nodes and packet forwarding path according to the network condition by employing the event-based mechanism and reinforcement learning technique. This allows low-latency energy-efficient scheduling and reduces the transmission collision between the nodes on the path. The Monte Carlo evaluation method is also adopted to minimize the overhead of the computation of each node in making the decision. Computer simulation reveals that the proposed scheme significantly improves end-to-end latency, waiting time, packet delivery ratio, and energy efficiency compared to the existing schemes including S-MAC and event-driven adaptive duty cycling scheme.

Temporal Differential Privacy in Wireless Sensor Networks

Sustaining the temporal privacy of an event in a wireless sensor network (WSN) is a critical task. From an adversarial point of view, the privacy of an event of interest can be breached by analyzing the traffic which emanates from a particular region. In this study, we present a differentially private technique for achieving temporal privacy by hiding the reporting traffic trace in the midst of other traffic traces. We achieve this objective by selectively delaying traffic traces at the nodes which are present in the routing paths of the messages to the sink. This mechanism prevents an adversary from gaining additional information about the time of occurrence of an event subjected to the presence or absence of traffic corresponding to a particular node. In this work, a packet forwarding path corresponding to a reporting event is modeled as an open queuing network. The temporal privacy associated with the event is measured by the jitter of the network. In our simulation, the minimum jitter for a basic FCFS and prioritized queuing network was estimated to be 0.45ms and 0.97ms respectively, whereas the jitter for the same networks after enforcing the privacy preservation mechanism was approximated to be 436.15ms and 503.42ms respectively. These results demonstrate the effects of differential privacy for concealing temporal information about the traffic corresponding to any node.

Escalator: An Autonomous Scheduling Scheme for Convergecast in TSCH.

Time Slotted Channel Hopping (TSCH) is widely used in the industrial wireless sensor networks due to its high reliability and energy efficiency. Various timeslot and channel scheduling schemes have been proposed for achieving high reliability and energy efficiency for TSCH networks. Recently proposed autonomous scheduling schemes provide flexible timeslot scheduling based on the routing topology, but do not take into account the network traffic and packet forwarding delays. In this paper, we propose an autonomous scheduling scheme for convergecast in TSCH networks with RPL as a routing protocol, named Escalator. Escalator generates a consecutive timeslot schedule along the packet forwarding path to minimize the packet transmission delay. The schedule is generated autonomously by utilizing only the local routing topology information without any additional signaling with other nodes. The generated schedule is guaranteed to be conflict-free, in that all nodes in the network could transmit packets to the sink in every slotframe cycle. We implement Escalator and evaluate its performance with existing autonomous scheduling schemes through a testbed and simulation. Experimental results show that the proposed Escalator has lower end-to-end delay and higher packet delivery ratio compared to the existing schemes regardless of the network topology.

A Split Architecture Approach to Terabyte-Scale Caching in a Protocol-Oblivious Forwarding Switch

Research has proven that in-network caching is an effective way of eliminating redundant network traffic. For a larger cache that scales up to terabytes, a network element must utilize block storage devices. Nevertheless, accessing block devices in packet forwarding paths could be a major performance bottleneck because storage devices are prone to be much slower than memory devices concerning bandwidth and latency. Software-defined networking (SDN) has entered into all aspects of network architecture by separating the control and forwarding plane to make it more programmable and application-aware. Protocol-oblivious forwarding (POF), which is an enhancement to current OpenFlow-based SDN forwarding architecture, enhances the network programmability further. In this paper, we proposed a novel split architecture to cope with the problem of speed mismatch between high-speed packet forwarding and low-speed block I/O operation over POF switches. The issues raised by this split architecture were first explored and could be summarized as packet dependency and protocol conversion. Then, we focused on solving these two problems and proposed an efficient and scalable design. Finally, we conducted extensive experiments to evaluate the split architecture along with the proposed approaches for packet dependency and protocol conversion.

Enhanced Flow Table Management Scheme With an LRU-Based Caching Algorithm for SDN

We propose a flow table management scheme for OpenFlow switches to minimize table-miss in a flow table. Commercial OpenFlow switches have one or more flow tables that consist of flow entries for processing packets. However, flow entries are managed based only on their timeout parameters, meaning they are expired and deleted by switches regardless of their reusability. The absence of the flow entry then causes table-misses in the future. We propose a solution for the problem of switches disregarding vacancies in the flow table when deleting expired flow entries. When a table-miss occurs, the corresponding switch must perform additional interactions with an OpenFlow controller to insert new flow entries, but this results in additional processing time and communication overhead. Previous studies aimed at solving this limitation have used sophisticated training sets or modified network architectures. In contrast, we propose a simple flow table management scheme with a least recently used-based caching algorithm to keep flow entries in an OpenFlow switch as long as possible. For this purpose, the switch continually adjusts its cache size according to the vacancy of each flow table and the controller determines the packet forwarding path through the switches by referring to the vacancies. We perform an experimental evaluation of the proposed scheme and demonstrate the performance gains in terms of the number of table-missed packets. We also analyze the effectiveness of the flow entry caching scheme using a mathematical model.

Tunnel-Free Scheme Using a Routing Table in a PMIPv6-Based Nested NEMO Environment

In this paper, we propose a novel tunnel-free scheme in a proxy mobile IPv6 (PMIPv6)-based nested network mobility environment; several mobile nodes (MNs) and mobile routers (MRs) compose a hierarchical wireless network topology. Because tunnels created by several MRs overlap and data packets travel along several local mobility anchors (LMAs), the utilization of the wireless section is reduced and the packet forwarding path of the wire-line section is not optimal. In our tunnel-free scheme, the mobile access gateway (MAG) plays an important role in both the wireless and wire-line sections. Using a local binding update, this tunnel-free scheme forwards data packets with a host-based routing table without any tunnel. Establishing a direct tunnel between the MAG and the last LMA, this scheme removes nested tunnels between intermediate LMAs and MRs, and optimizes the forwarding path to the MN in the wire-line section.

Enhancements to FPMIPv6 for improved seamless vertical handover between LTE and heterogeneous access networks

Fast handovers for proxy mobile IPv6 (FPMIPv6) was created to reduce packet-delay that occurs during proxy mobile IPv6 (PMIPv6) handover. Based on vertical handover (VHO) experiments conducted between Long Term Evolution (LTE) and heterogeneous accesses over the evolved packet core (EPC) using FPMIPv6, it was recognized that consistently reliable seamless VHO operations were difficult to accomplish due to limitations in FPMIPv6. Noticeably, VHO performance degradation resulted from the serving network (SN) lacking information of the target network (TN) when the TN is a heterogeneous protocol domain, packet congestion and loss problems occurring on specific network gateway interfaces, and also from using long packet-forwarding paths. In this article, an enhanced FPMIPv6 technique is proposed to solve these problems and improve the VHO operation by using shorter data-paths and improved coordination of buffered packet-forwarding and TN switching, which results in a significantly reduced packet-delay.

Router group monitoring: making traffic trajectory error detection more efficient

Detecting errors in traffic trajectories (i.e., packet forwarding paths) is important to operational networks. Several different traffic monitoring algorithms such as Trajectory Sampling, PSAMP, and Fatih can be used for traffic trajectory error detection. However, a straight-forward application of these algorithms will incur the overhead of simultaneously monitoring all network interfaces in a network for the packets of interest. In this paper, we propose a novel technique called router group monitoring to improve the efficiency of trajectory error detection by only monitoring the periphery interfaces of a set of selected router groups. We analyze a large number of real network topologies and show that effective router groups with high trajectory error detection rates exist in all cases. However, for router group monitoring to be practical, those effective router groups must be identified efficiently. To this end, we develop an analytical model for quickly and accurately estimating the detection rates of different router groups. Based on this model, we propose an algorithm to select a set of router groups that can achieve complete error detection and low monitoring overhead. Finally, we show that the router group monitoring technique can significantly improve the efficiency of trajectory error detection based on Trajectory Sampling or Fatih.

Packet Forwarding Scheme Based on Interworking Architecture for Future Internet

This paper introduces a packet forwarding scheme based on interworking architecture that can provide quite a good QoS by minimizing processing delay which is the major part of the timeliness factor in New Generation IP-based networks. Based on path and resource reservation mechanism, the POSIA makes routers on the packet forwarding path synchronize with each other and then forward packets. We have shown that the POSIA outperforms the existing packet forwarding schemes like IntServ, DiffServ and MPLS through computer simulations using OPNET.

The impact of multihop wireless channel on TCP performance

This paper studies TCP performance in a stationary multihop wireless network using IEEE 802.11 for channel access control. We first show that, given a specific network topology and flow patterns, there exists an optimal window size W* at which TCP achieves the highest throughput via maximum spatial reuse of the shared wireless channel. However, TCP grows its window size much larger than W* leading to throughput reduction. We then explain the TCP throughput decrease using our observations and analysis of the packet loss in an overloaded multihop wireless network. We find out that the network overload is typically first signified by packet drops due to wireless link-layer contention, rather than buffer overflow-induced losses observed in the wired Internet. As the offered load increases, the probability of packet drops due to link contention also increases, and eventually saturates. Unfortunately the link-layer drop probability is insufficient to keep the TCP window size around W'*. We model and analyze the link contention behavior, based on which we propose link RED that fine-tunes the link-layer packet dropping probability to stabilize the TCP window size around W*. We further devise adaptive pacing to better coordinate channel access along the packet forwarding path. Our simulations demonstrate 5 to 30 percent improvement of TCP throughput using the proposed two techniques.

Dynamic Aggregation of Reservations for Internet Services

Global availability of on-demand services with an associated guaranteed quality-of-service (QoS) is still missing in the Internet today. The Differentiated Services architecture achieves scalability in the data plane by treating all flows with a specific type of service as one aggregate. In order to provide guaranteed end-to-end reservations, the control plane (e.g., performing admission control and management of resource reservations) has to be scalable as well. The DARIS architecture provides this essential linkage between scalability in the packet forwarding path and scalability of QoS management in the Internet. It comprises a novel concept of dynamic and hierarchical aggregation, which acts on the network level of autonomous systems (ASes). This relieves management entities in intermediate ASes of processing load by reducing their managed reservation states as well as the number of signaling messages that have to be processed significantly. Moreover, novel and special support for aggregation by a dedicated signaling protocol mechanism is provided.