Network function virtualization (NFV) flexibly provides servoces by virtualizing network functions on a general-purpose server, and attracted research interest in recent years. In NFV environment, providing service chaining, which dynamically connects each network function (virtual network function: VNF), is critical issue. However, as it is challenging to select the optimal sequence of VNF services in the service chain in a decentralized manner, the distances between the VNFs tend to increase, leading to longer communication and processing delays. Furthermore, it has never considered that certain VNFs that can be exchange the order of services with one another. To address this problem, in this paper, we propose a distributed search method for ordered VNFs to reduce delays while considering the load on control server, by exploiting an in-network guidance technology, called Breadcrrmubs, for query messages.

In content oriented networks (CON), routers in a network are generally equipped with local cache storages and store incoming contents temporarily. Efficient utilization of total cache storage in networks is one of the most important technical issues in CON, as it can reduce content server load, content download latency and network traffic. Performance of networked cache is reported to strongly depend on both cache decision and content request routing. In this paper, we evaluate several combinations of these two strategies. Especially for routing, we take up off-path cache routing, Breadcrumbs, as one of the content request routing proposals. Our performance evaluation results show that off-path cache routing, Breadcrumbs, suffers low performance with cache decisions which generally has high performance with shortest path routing (SPR), and obtains excellent performance with TERC (Transparent En-Route Cache) which is well-known to have low performance with widely used SPR. Our detailed evaluation results in two network environments, emerging CONs and conventional IP, show these insights hold in both of these two network environments.

These days, in addition to host-to-host communication, Information-Centric Network (ICN) has emerged to reflect current content-centric network usage, based on the fact that many users are now interested not in where contents are but in acquired contents themselves. However, current IP network must still remain, at least from deployment perspective, as one of near future network architectures. This is because ICN has various scalability and feasibility challenges, and host-to-host communication is also diffused like remote login, VoIP, and so on. Therefore, the authors aim to establish the feature of ICN on conventional IP network to achieve feasible and efficient architecture. We consider that, as a feasible and efficient architecture, only user-edges keep some contents' caches within their computational and bandwidth limitations and contents should be replicated also on some replica servers dispersedly to assure contents' distribution even if user caches are not found. To achieve this, in this paper, we propose to operate Content Delivery Network (CDN) and Breadcrumbs (BC) frameworks coordinately on IP network. Both CDN and BC are important as a content-centric technique. In CDN, replica servers called surrogates are placed dispersedly in all over the Internet. Although this provides users with contents from nearer surrogate servers, the surrogate servers have higher workload to distribute contents to many users. In the proposed method, in cooperation with BC method that is proposed to implement ICN on IP network, the surrogate server workload is drastically reduced without largely increasing hop count for content delivery. Although it needs some functions to implement our approach such as adopting BC architecture to routers, calculating and reporting information required for cooperation of BC method with CDN, the cost for the functions in our solution is not so significant. Finally, we evaluate the proposed method with CDN we carefully modeled through simulation.

What should be the ultimate form of the cloud computing environment? The solution should have two important features; “Fine-Granularity” and “Participation.” To realize an attractive and feasible solution with these features, we propose a “participating fine-grained cloud computing platform” that a large number of personal or small-company resource suppliers participate in, configure and provide cloud computing on. This enables users to be supplied with smaller units of resources such as computing, memory, content, and applications, in comparison with the traditional Infrastructure as a Service (IaaS). Furthermore, to search for nearby resources efficiently among the many available on the platform, we also propose Resource Breadcrumbs (RBC) as a key technology of our proposed platform to provide in-network guidance capability autonomously for users' queries. RBC allows supplier-nodes to distribute guidance information directed to themselves with dedicated control messages; in addition, the information can be logged along the trail of message from supplier to user. With this distributed information, users can to autonomously locate nearby resources. Distributed management also reduces computational load on the central database and enables a participating fine-grained cloud platform at lower cost.

Lately, access loads on servers are increasing due to larger content size and higher request frequency in content distribution networks. Breadcrumbs (BC), an architecture with guidance information for locating a content cache, is designed to reduce the server load and to form content-oriented network autonomously in cooperation with cached contents over IP network. We also proposed Breadcrumbs+ which solves BC's endless routing loop problem. However, Breadcrumbs takes only a passive approach; BC entries are created only when a content is downloaded and only at routers on the download path but not at any other routers. We expect that active and adaptive control of guidance information with simple complexity improves its performance with keeping scalability. In this paper, we propose Active Breadcrumbs which achieves efficient content retrieval and load-balancing through active and adaptive control of guidance information by cache-nodes themselves. In addition, we show the effectiveness of Active Breadcrumbs through the extensive computer simulation.

This paper proposes Burst Error Resilient coding (BRC) technology in mobile broadcasting network. The proposed method utilizes Scalable Video Coding (SVC) and Forward Error Correction (FEC) to overcome service outage due to burst loss in mobile network. The performance evaluation is performed by comparing PSNR of SVC and the proposed method under MBSFN simulation channel. The simulation result shows PSNR of SVC equal error protection (EEP), unequal error protection (UEP) and proposed BRC using Raptor FEC code.

An orthogonal sequence based MIMO common feedback method for multicast hybrid automatic-repeat-request (H-ARQ) transmission is presented. The proposed method can obtain more diversity gain proportional to the number of transmit antennas than the conventional on-off keying (OOK) based common feedback method. The ACK/NACK detection performance gain of the proposed scheme over the OOK based method is verified by analysis and computer simulation results.

Mobile telecommunication is a rapidly growing market. Second generation systems such as GSM, DECT and ERMES, which are actually in an evolving status will be replaced by the third generation UMTS from the beginning of the next century on. While UMTS will allow data communication with up to 2Mbit/s, the fourth generation system MBS will provide up to 155Mbit/s. In several European R & D projects of the ESPRIT, DRIVE, COST and RACE programmes investigations concerning network planning, network operation, signalling, access techniques, security, terminal development and image and voice compression are carried out in order to create the scientific and technological bases for future UMTS and MBS. Some of these projects are described in more detail and an outlook toward future R & D activities is given. Finally some considerations are made concerning expectations of future services and questions concerning the development of wide band versus narrow band solutions are put.