Chikara Sasaki

Rapid Channel Zapping for IPTV Broadcasting with Additional Multicast Stream

This paper proposes a novel approach for improving channel zapping delay on IPTV broadcasting services. Channel zapping delay is a crucial issue for digital TV broadcasting, which entails audio/video data buffering before reproduction. Such delay could be mitigated in an IP environment if a receiver accelerated this buffering using additional burst transmissions from dedicated servers when a channel zap occurs. However, most conventional solutions are based on the unicast burst, which may cause an impulsive server/network load because channel zaps tend to happen simultaneously when programs are finished or suspended by commercial messages. To reduce this load, we propose a new multicast-based solution that takes into consideration the timing variation in channel zap on each receiver. We have confirmed a maximum 1-second reduction in the zapping delay using commercial multicast streams.

Splitting Control-User Plane on Communication Protocol for Spotty Network

The rapid increase in traffic is a serious problem for mobile carriers. As the radio spectrum is a limited resource and mobile traffic is expected to continue increasing, utilizing multi-frequency bands will play an increasingly prominent role in relieving traffic overload. Extremely high-frequency bands, such as millimeter wave bands, can provide high-speed wireless data transfer at more than 1 Gbps, their use, nevertheless, presents challenges due to the inherent limitation of directionality and strong absorption. This paper presents a novel communication scheme utilizing millimeter wave bands for mobile data traffic off-loading. The design is based on Content-Centric Networking (CCN) and is evaluated on actual equipment with a model-based analysis. The proposed scheme achieves significant reduction in download time by taking advantage of the CCN architecture, which includes connection-less data streams and location decoupling, and by an ingenious use of local caching. This paper presents a protocol design and its evaluation on actual implementation.

Implementation Approach for Network Coding using External Devices in IP Multicast

Network coding is a novel technique to improve network throughput and performance by efficient encoding over the intermediate nodes in the network and works particularly well in multicasting. We expect that network coding will reduce the bandwidth utilization of IP broadcasting services that provide multichannel services and high quality videos using IP multicast. However, it is difficult to apply network coding to commercial networks because the routers actually used have no coding functions. In this paper, we propose a scheme that achieves network coding for IP multicast. It works by attaching external devices to routers instead of replacing them with network coding routers and can be applied to gigabit network by avoiding packet transmission excluding the target multicast.

A Framework for Viewer Counting of Streaming Service with IP Multicast

In this paper, we study a viewer counting method for multicast-based IPTV services. Recently, streaming services over an IP network, such as IPTV and/or Internet radio, have become popular, as a result of the rapid deployment of broadband access. IP multicast is an effective technology for simultaneous distribution of content to many viewers. However, it is difficult to grasp the number of viewers, since IP multicast does not require any direct communication from viewers to the distribution server, only to the adjacent router. We propose a novel viewer counting method from the carriers perspective using multicast forwarding information from the distribution network. Our experimental results indicate that the proposed method is expected to obtain a rating of 100,000 viewers every 1 minute.

Development and evaluation of LISP-based instant VPN services

The Locator/ID Separation Protocol (LISP) is being standardized in IETF, which separates the IP address functionality into routing locators (RLOC) and endpoint identifiers (EID). LISP is applicable for instant Virtual Private Network (VPN) services because it has IP tunneling features. However, there are two main issues with application to VPN. One is a Map server/Map resolver (MS/MR) basically allows any third party to know a mapping table even if it is irrelevant to the VPN. The other is an MS/MR should identify the VPN to which the requested site belongs because the requested EIDs can be private addresses and may overlap with other VPN sites. A simple solution is to deploy an independent MS/MR for every VPN. However, this is undesirable from a cost perspective. We present a new LISP-MS/MR that provides a large number of VPN services using a single set. This MS/MR creates a logically separated EID-to-RLOC mapping table for each VPN and selects an appropriate type according to the requesting VPN site. To ensure this, our scheme uses Authentication data included in the Map register for an initial VPN identification of the registering site and associates the identified VPN ID with the registered RLOC. In following Map requests, the appropriate mapping table for the requesting VPN site is selected based on its RLOC. We confirmed the basic network functions of VPN using the prototype system. The results of scalability tests show that our MS/MR completes the transaction for nearly-simultaneous 10,000 Map registers or requests within three seconds.

Hybrid sampling for estimating flow size distribution and its implementation

Recently, it has been necessary to perform traffic sampling in order to deteriorate the load of capturing and analyzing processes, as the amount of ISP traffic grows. Packet sampling and flow sampling are main sampling techniques. In order to estimate flow size distribution from sampled data, each sampling method has its own advantages and disadvantages. Flow sampling can extract flows in proportion to the original flow size distribution but is difficult to extract large-sized flows due to the heavy-tailed flow size distribution. On the other hand, packet sampling can extract large-sized flows but complete flows cannot be extracted. In this paper, we propose a hybrid sampling method which performs both flow sampling and packet sampling in parallel to utilize both advantages of above two methods and improve estimation accuracy. We also propose cost-effective implementation which employs a general-purpose switch. By verifying with real traffic data, we confirmed the effectiveness of our proposed method in terms of reproducibility.

Multicast Tree Discovery Scheme with Selective Router Access

In this paper, we present a multicast tree discovery scheme reducing the number of routers to access. Recently, the broadcasting of rich content via IP multicast has been increasing. Network and/or service operators require continuous and accurate multicast tree discovery because a multicast tree can be changed dynamically by join/leave events among users, network failure, and so forth. Our newly proposed tree discovery scheme can avoid unnecessary router accesses considering unicast and multicast routing information in addition to multicast delivery characteristics. Simulation results show that our proposed scheme can discover a multicast tree by accessing fewer than half of the routers in the whole network.