Remote driving of vehicles using in-vehicle camera videos is essential for the uncrewed operation of automated vehicles. A remote operator views the in-vehicle camera videos to understand the situation around the vehicle and sometimes performs remote driving. Therefore, it is essential to satisfy three in-vehicle camera video transmission requirements: high image quality, low latency, and high reliability. Sub-6 and mm-Wave 5G networks are capable of high throughput and low latency video transmission and attract attention as a means of in-vehicle camera video transmission. However, 5G networks with high frequencies have narrower coverage than the existing 4G networks and are easily affected by object blockage. Therefore, cases of a sudden deterioration in network quality are likely to occur. Therefore, using 5G networks to transmit in-vehicle camera videos requires coping with sudden network quality deterioration. This paper proposes an in-vehicle camera image transmission system using 5G and 4G networks. In the proposed system, when the system detects a disturbance in the video transmitted via the 5G networks, it switches the display to the video transmitted via the 4G networks. When the 5G networks are available, the system displays the video with high quality and low latency. When unavailable, the system switches to the video transmitted via the 4G networks. We have confirmed on the network simulator that the proposed system has a shorter latency than the video transmission system using a jitter buffer to ensure reliability. In a video transmission experiment using commercial Sub-6 5G networks, we confirmed that the proposed system could detect all video disturbances and avoid the displayed video's disturbance by switching the video.

Teleoperation is a crucial technology for unmanned autonomous vehicles. When an autonomous vehicle does not work as desired, an operator teleoperates the vehicle and drives it to a safe place. Therefore, driving accuracy is essential in teleoperation. In teleoperation, a latency, consisting of transmission time and signal processing time, exists and impairs driving accuracy. A latency visualization method, which shows the gap due to latency between the vehicle's actual position and the position that the driver can see on the on-board camera videos, is considered a promising solution. Several studies have shown the latency visualization method's effectiveness through simulation-based evaluations, but it has not been evaluated in a real environment. In this paper, we proposed a latency visualization method that can be implemented in a real environment, where the latency can change frequently, and evaluated the method through a user test. The results show that the proposed latency visualization method improves driving accuracy in a real environment, and the improvement is more significant with longer latency.

Network delay may occur on the LTE (Long Term Evolution) network due to signaling spikes. This decreases quality of experience (QoE). In this paper, we propose a method for mitigating the effect of such a delay. Our method acts as “a concierge” to divert the attention of users away from delay. The biggest advantage of our method is that it can be implemented at lower cost (e.g. capital investment) compared to other methods. To evaluate our method, we conducted a comprehensive user experiment using crowdsourcing. The results show the effectiveness of our method.

The rapid growth of smartphone based User Equipment (UE) and the wide development of LTE networks have changed the traffic pattern of mobile applications. Today, many applications running on smartphones periodically generate background traffic by sending and receiving messages or retrieving updates (i.e. without user interaction). Since each activity requires the UE to first attach and then to detach from the LTE network, a large volume of signaling traffic is generated. When the timing of these activities synchronizes among many UEs, a storm of signaling traffic is caused. We refer to this phenomenon as a signaling spike. Such a spike is a serious risk for telecom operators as it may overload its gateways and eventually disrupt services. As a way to suppress these spikes, we propose a new approach called a user equipment based network access control scheme (UENAC). The aim of UENAC is to autonomously decentralize the access timing among of UEs by adding a variable delay before sending packets upon attachment to the LTE network. We implement the UENAC entity on a commercial Android smartphone and show that the scheme has no negative effect on existing applications with delays up to 8 seconds. Furthermore, we simulate the signaling traffic based on commercial traffic pattern and show that the proposed scheme is able to effectively decentralize signaling spikes.

The market for multiplayer online games is rapidly growing in concert with the growth in broadband Internet connection services. Since such games share a virtual space among many players, it is important to match players to a group so that they share low-latency connections with each other. This is because the latency between them affects the perceived quality of their experience. In this paper, we propose a topology-aware matching algorithm using players' geographical locations. We focus on synchronous multiplayer games that require a latency comparable to a delay of one frame. This paper describes the algorithm and its evaluation by simulations.

In this paper, we first describe the challenges of provisioning Wi-Fi equipped M2M devices, which may be behind Network Address Translation (NAT). We then articulate an automatic over-the-air provisioning mechanism that includes four steps: device discovery, user account setup for device, ESSID/IP configuration, and device registration (including NAT tunnel configuration). The mechanism enables M2M service providers to manage the registered M2M devices and allows M2M users to access these M2M devices behind NAT using a unique fully qualified domain name (FQDN). Finally, we elaborate the performance analysis and technical discussions related to the automatic provisioning mechanism.

Recently, content delivery services using the P2P architecture have been growing rapidly over the Internet. ISPs are suffering from network congestion due to the increase in traffic volume. For efficient delivery of P2P traffic, the IETF ALTO WG (Application-Layer Traffic Optimization) has been working on the standardization of the ALTO service for controlling P2P traffic. In addition, ALTO services have a ranking service, which is providing the ranking value indicating the peer selection priority using the BGP attribute. In this paper, we propose the mechanism of an ISP-Friendly with ALTO-like server called “n-Tracker”, which provides a ranking service that applies the ISP's own policy flexibly. This mechanism defines the ranking value according to the P2P peer selection policy for the ISP using not only the BGP attributes received from external ASes but also ISP own policies statically configured by ISP operators. We evaluated the performance of the n-Tracker, which was running on a 1U PC server. For example, we evaluated the processing time to reflect the policies when it received the approximately 310,000 BGP routes and the n-Tracker's average response time for each request from the client. We validated that they took 19.57 sec and 2.30 msec, respectively. In addition, we showed that the priority for the peers changed depending on the configuration of the policies configured in the n-Tracker, and we validated that download traffic could be controlled by the peer selection policy.

The current interdomain routing protocol, BGP, is not resilient to a path failure due to its single-path and slowly-converging route calculation. This paper proposes a novel approach to improve the resilience of the interdomain communication by enabling a set of ASes to form an alliance for themselves. The alliance members cooperatively discover a set of disjoint paths using not only the best routes advertised via BGP but also the ones unadvertised. Since such a set of disjoint paths are unlikely to share a link or an AS failure, a member AS can provide a pair of the other members with a transit to circumvent the failure. We evaluate how many disjoint paths we could discover from both advertised and hidden (unadvertised) routes by analyzing publicly available BGP route data. Our feasibility study indicates that an alliance of ASes can establish a set of disjoint paths between arbitrary pair of its alliance members to improve the resilience of interdomain routing among the members.

This paper proposes a point-to-multipoint (P2MP) Multi-Protocol Label Switching (MPLS) based hierarchical service management system. Traditionally, general management systems deployed in some service providers control MPLS Label Switched Paths (LSPs) (e.g. RSVP-TE, LDP) and services (e.g. L2VPN, L3VPN and IP) separately. In order for the dedicated management systems for MPLS LSPs and services to cooperate with each other automatically, a hierarchical service management system has been proposed with the main focus on point-to-point (P2P) TE LSPs in MPLS path management. In the case where P2MP TE LSPs and services are deployed in MPLS networks, the dedicated management systems for P2MP TE LSPs and services must work together automatically. Therefore, this paper proposes a new automatic correlation between P2MP TE LSPs and each service. In particular, this paper proposes a new algorithm for a correlation between P2MP TE LSPs and multicast VPN services. The capacity and performance searching on both a sub-LSP and correlation tables are evaluated, and the results show this system is very scalable within real MPLS production networks. This system, with automatic correlation, appears to be deployable in real MPLS production networks.

If a problem with IP communication occurs, IP network operators refer to the routing tables of the affected routers to check the routes to the destinations. There are a number of methods currently used for referring to routing tables. However, operators cannot refer to past routing tables using existing methods. The past routing tables are useful for IP network operation. For example, operators can find out how the influence of a network problem on routes spreads to the network by checking fluctuations in each routerpsilas routing table. In this paper, we propose a method of collecting every routerpsilas routing table within a domain based on the monitoring of routing protocols. In our method, we collect routing protocol messages and calculate all routerspsila routing tables within a domain in a concentrated manner using the same way where each router within a domain calculates its routing table. Routing tables are calculated whenever route status in IP networks changes, and calculated routing tables are stored so that operators can refer to them at any time in the future.

As the Internet has become a communication infrastructure, inter-domain routing instabilities have become prone to serious problems. Some studies have proposed methods that infer instabilities and their locations by clustering BGP update messages collected at multiple observation points and are based on post-processing using public messages. However, to realize real-time processing, which is vital for network operations, single point observation is a feasible option with costs and today's competitive environments in mind. Therefore, we propose an inference method including a new clustering algorithm that is suitable for messages collected at a single observation point. We also describe the empirical results used to validate our method.

It is important to monitor routing protocols for stable operation of IP networks. In this paper, we focus on Open Shortest Path First (OSPF), a widely deployed intra-domain routing protocol. Routers running OSPF advertise their link states on Link State Advertisements (LSAs) to the network so the location of OSPF failures on the IP network can be detected by monitoring LSAs. However, in order to identify OSPF failures correctly, it is necessary to consider the association of multiple flooded LSAs when OSPF failures occurred and LSA delay. In this paper, we propose a method of OSPF failure identification based on LSA flooding analysis taking these aspects into account.

As a result of the spread of Gigabit Ethernet technologies, we need to realize Internet monitoring systems with gigabit-rate capability using commodity hardware. However, it is quite difficult for existing systems just to collect all the packet headers at a gigabit rate even if high-end hardware components are used. In order to support gigabit rate traffic, we propose a novel framework on packet header collection which can be applied to most network interface cards. Our evaluation results show that our first implementation can collect 100% of header information, even in the case that a Gigabit Ethernet link is fully utilized by 384-byte packets, while existing software-based systems can collect less than 50% in spite of using more than twice the CPU resources.