Search

The communication paradigms for Delay/Disruption Tolerant Networks (DTN) have been modeled after email. Supporting email over DTN in a backwards compatible manner in a heterogeneous environment has yet to be fully defined. In the Simple Mail Transfer Protocol (SMTP) based on TCP/IP used in the existing terrestrial Internet, the protocol works through multiple interactions between the sender’s mail server and the receiver’s mail server. However, in the space Internet environment, since the contact times are limited, reliability cannot be guaranteed for the interaction between the server and the client used in the existing SMTP. Therefore, this paper proposes a novel mail transfer protocol, DTN-SMTP for space Internet over DTN. To minimize the interaction of the existing SMTP, it relies on one-way transmission and optionally performs retransmission mechanisms. Finally, we have built and configured two DTN nodes to implement DTN-SMTP. Also, we have confirmed the mail’s reception and the file attachment from the external mail client with minimized interactions between the SMTP messages.

Delay/Disruption Tolerant Networking (DTN) is an approach suitable for networks where end-to-end connections are not guaranteed. In this paper, the energy-based routing with rendezvous is proposed to improve delivery probability of important messages in DTN-based UAV networks. The main idea for achieving this goal is to introduce the rendezvous mode for DTN-based UAV networks, whether to hover or to follow. Simulation was performed using Opportunistic Network Environment (ONE). The simulation results showed that the proposed routing scheme with rendezvous has a larger delivery probability for important messages despite their sizes, compared to the previous routing scheme without rendezvous.

The industry 4.0 and Industrial IoT is leading new industrial revolution. Industrial IoT technologies make more reliable and sustainable products than traditional products in automation industry. Industrial IoT devices transfer data between one another. This concept is need for advanced connectivity and intelligent security services. We focus on the security threat in Industrial IoT. The general security systems enable to detect normal security threat. However, it is not easy to detect anomaly threat or network intrusion or new hacking methods. In the paper, we propose autoencoder (AE) using the deep learning based anomaly detection with invasion scoring for the smart factory environments. We have analysis F-Score and accuracy between the Density Based Spatial Clustering of Applications with Noise (DBSCAN) and the autoencoder using the KDD data set. We have used real data from Korea steel companies and the collected data is general data such as temperature, stream flow, the shocks of machines, and etc. Finally, experiments show that the proposed autoencoder model is better than DBSCAN.

In this paper we describe the security vulnerabilities of the Erle-Copter quadcopters. Due to the fact that it is promoted as a toy with low acquisition costs, it may end up being used by many individuals which make it a target for harmful attacks. In addition, the video stream of the drone could be of interest for a potential attacker due to its ability of revealing confidential information. Therefore, we perform a security threat analysis on this particular family of drones. We set the focus mainly on obvious security vulnerabilities like the unencrypted Wi-Fi connection or the user management of the GNU/Linux operating system which runs on the drone. We show how the drone can be hacked in order to hijack the Erle-Copter. Our aim is to sensitize the end-user of Erle-Copters by describing the security vulnerabilities and to show how the Erle-Copter can be secured from unauthorized access. We provide instructions to secure the drones Wi-Fi connection and its operation with the official smartphone app or third party PC software.

Wireless network devices are used for the Internet of Things in a variety of applications, and although the IoT has many benefits, there are some security issues in this area. Hacking tools that are widely used in wireless communication enable the attacker to export the information stored in the device memory. Devices within the IoT should not allow this information to be accessed without an authentication. In this paper, we propose an efficient device authentication protocol without certification authority for the Internet of Things. Compared to the existing Constrained Application Protocol, the proposed protocol increases efficiency by minimizing the number of message exchanges. Since our protocol is based on a keyed hash algorithm, the Certificate of Authority is not required. Experimental results show that the proposed authentication protocol improves the security level and reduces the resource consumption of devices.

This paper proposes a secure group management scheme for the join/leave procedures of UAV squadrons. All public keys of the group members are owned by the leader of the group. In the join procedure of the groups, the public keys are exchanged by the leader of each group to generate a session key of each UAV. The leader generates a group matching key using the session key and broadcasts it to the member. Each member of the group generates a group key using the group matching key. Therefore, the entire UAV does not need to communicate with each other and proceed leave procedure. This minimizes the public key transmission cost and the number of group key renewals. As a result, the newly created group renews the new group key and can exchange the information securely between the groups using this group key. We derive the proposed scheme as a formula and visualize the cost in the join/leave procedures. For objective evaluation, we show the comparison between the existing join/leave procedures and the proposed join/leave procedures.

Internet of Things (IoT) can be defined as an intelligent infrastructure service that provides the means by which information can be exchanged through the interconnection of devices and people. While IoT services continue to be developed, the need to overcome its drawbacks is great. One weakness of IoT is that its technical characteristics expose it to diverse security threats. Because technical equipment has several limitations including restrictive hardware options and low power, it is vulnerable to physical attack or other security threats. In particular, universal plug and play (UPnP) plays a crucial role in connecting heterogeneous devices for IoT services to enable information exchange between them. However, UPnP has inherent security-related drawbacks because it is operated using simple service discovery protocol and user datagram protocol (UDP). Solving the issues of network security and access by unauthorized users is now critical. In this paper, we analyze security vulnerabilities of UPnP, define the rules for distributed Denial-of-service attack situations, attempt to overcome the drawbacks of Software-defined-networking (SDN)-based network intrusion detection systems. Also, we propose to establish an internal IP address of a network device in the virtual environment and present rules to prevent attack scenarios.

In these days, the beacon has been widely used in all aspects of life. It can be used in marketing and loyalty, based on the location of advertisements or messages. But it has not been applied to the disaster environment. Recently, the disasters such as fire disaster and earthquake occur frequently around the world. They cause great threats to life and property. However, Modern architectures have high-rise and complex features that bring danger and greater challenges to the search and rescue work for firefighters. This paper proposes the design and implementation for a portable, power saving dual-mode beacon profile. The dual-mode beacon not only has the function of sending an advertisement, but also can sense the fire and earthquake to send out alarms. This system supports both the original beacon system and the disaster system. The beacon system gives you advanced information using Indoor Positioning System, while the disaster system helps you to exit and service escape route.

Recently, the need for telemedicine services and user`s service requirements are increasing, the research for more convenient telemed service is underway in various fields. In this paper, we propose that Integrated telemedicine system possible to regular health care. unlike the existing telemedicine system, we combine the voice communications systems and biometric information based on CPS (Cyber Physical System) using wireless communication sensor and elderly people who disabilities are transmit the information comfortably, Also doctors in correspondent site are able to improves the accuracy of the medical treatment by received information about biometric and audio communication. In addition Health status information is stored selectively and then doctor can check the elders status everytime and everywhere. In this paper, we designed the telemedicine system suitable for korea aging society situation, therefore we could offer the Elderly-friendly medical service for seniors who live in silver town.

Background/Aims: Telemedicine is a convenient and efficient tool for remote education in various fields. The telemedicine system can also be used to educate doctors and medical students. The aim of our study was to establish the effectiveness of the telemedical system for use in a live endoscopic multichannel demonstration conference and to test the effectiveness and usefulness of a multicenter-based live endoscopic demonstration through live, interactive, high resolution video transmission using advanced networks and the digital video transport system (DVTS). Methods: This study is a prospective multicenter pilot study. A live demonstration of an endoscopic submucosal dissection (ESD) and an endoscopic retrograde cholangiopancreatography (ERCP) using advanced network technology was performed. Results: The DVTS successfully transmitted uncompressed, high-resolution, digital lectures with endoscopy video during a multichannel endoscopic live demonstration of ESD and ERCP over multiple advanced networks. The overall satisfaction rating when the endoscopic lecture demonstration was performed by combining DVTS was generally good. Conclusions: We believe that a multicenter-based live endoscopic demonstration is a very effective conferencing method when using ad vanced networks and DVTS.

In this paper, we have shown Dalvik virtual machine implementation to reduce the profiling overhead from the trace of the JIT compiler for the specific method. By running the same Java method on the original Dalvik VM and the modified Dalvik VM, we have achieved around 30% performance improvement with this algorithm. In this paper, to increase the reader`s understanding of Android Dalvik virtual machine, we will explain the architecture of Dalvik JIT compiler and we will provide the detailed explanation with source codes for modified parts of Dalvik virtual machine. From the industry perspective, we can expect competitive benefits over the competitors with performance improvement in Android core.

In this paper, we propose the design and implementation of the storage-based data sharing system in the separate network environment to improve efficiency of data transmission. The previous system generates files per received packet and transmit files to another network through storage. This system causes inefficiency by reading unnecessary blocks, when it transmits a number of files through storage. Our proposed system deals with this inefficiency by adopting concept of snapshot. Consequently, we create one file with snapshot so that the number of files can be reduced and the file size can be optimized according to the block size. The proposed system improves the response time significantly with the minimized reading of unnecessary blocks, compared to the previous system.

This paper attempts to propose a method to improve the snapshot boot method, one of the methods to enhance the booting speed of the embedded Linux based system and to increase its efficiency. Snapshot boot is a method of using suspend/resume that is a method of saving and restoring the entire information of the current tasks, and it enhances the booting speed by processing a restoration of previous tasks from the bootloader instead of processing the Linux booting. The facing problem of snapshot boot is that it takes a long time to create images and save them to the storage device during the suspend process since it targets every pages. Additionally, if the switch is turned off while creating an image by some extraordinary circumstances, then the image is not created and thus, the resume process of snapshot boot cannot be executed. The suggest method in this paper creates the snapshot image for once only and utilize the image to enhance the speed and stability on booting.

The change in performance of the mobile communication field took place due to jumping development of technology, so high performance terminals that anyone can directly search and amend desired information anywhere and anytime, namely, the mobile communication terminals called Smartphone were released to the market. The terminal can store informations that an individual stored, for example, call log, where to make contact and address of acquaintances, transmit/receive message and mail, photographs and videos, etc., but there are worries on surreptitious use of other people due to leaking of personal information through loss or theft of these terminals because of several reasons, so the present thesis aims to realize a method that remotely control information inside a terminal in case of loss of a mobile communication terminal.

In the field of document editing, a real-time collaborative editing that multiple users edit a same document simultaneously has been actively studied. The co-editing session should be kept for the synchronization about the changes during the real-time collaborative editing of documents among the participants. If the session ends during collaborative editing, they wouldn’t be able to continue co-editing anymore. The purpose of this study is to develop a framework for Continuous Real-time Collaborative Editing that disconnects the session in unintended situations. Participants should be able to terminate editing at any time in opened co-editing session, and a certain participant is able to disconnect because of unstable networks. In this case, the editing session should be maintained without termination.

We propose a discovery support scheme for inter-domain DDS gateways to reduce the completion time of the discovery process. Since the conventional inter-domain services are regardless of the unbalanced EDPs load among the gateways, several problems occurs such as the delaying of completion time. Therefore, in this paper, we address the problem of completion time.

The goal of this paper is to explain the design and implementation of network infrastructure based on wireless sensor networks in a building. The network infrastructure helps evacuate the people from a disaster such as fire or bombing due to humidity, intensity of illumination etc., based on collected local information. The system considers the population supporting the direction of proper evacuation. Moreover, the collected and expected local information will be given to the rescue team. The adaptive evacuation guidance system based on real time local information can help the people in that disaster, since it will guide them to a safer area or to the exit.

This paper describes the design and performance of a new ATM adaptation layer protocol lAALdTr for improving TCP performance over wireless ATM networks. The wireless links are characterized by higher error rates and burstier error patterns in comparison with the fiber links for which ATM was introduced in the beginning. Since the low performance of TCP over wireless ATM networks is mainly due to the fact that TCP always responds to all packet losses by congestion control, the key idea in the design is to push the error control portion of TCP to the AAL layer so that TCP is only responsible for congestion control. The AALdT is based on a novel and reliable ARQ mechanism to support qualitydcritical TCP traffic over wireless ATM networks. The proposed AAL protocol has been validated using the OPNET tool with the simulated wireless ATM network. The simulation results show that the AALdT provides higher throughput for TCP over wireless ATM networks compared to the existing approach of TCP with AAL 5.

In future wireless multimedia networks, there will be a mixture of different traffic classes which have their own maximum tolerable bit error rate (BER) requirements. In this paper, a novel medium access control (MAC) protocol called wireless multimedia access control protocol with BER scheduling (in short form, WISPER) for CDMA-based systems is proposed. WISPER utilizes the novel idea of scheduling the transmission of multimedia packets according to their BER requirements. The scheduler assigns priorities to the packets, and performs an iterative procedure to determine a good accommodation of the highest-priority packets in the slots of a frame so that packets with equal or similar BER requirements are transmitted in the same slots. The proposed WISPER protocol has been validated using a software emulator on the cellular environment. Performance evaluation results based on the implementation are also included.

In this paper, we design and implement a real-time monitoring system based on CPS (Cyber Physical System) for telemedicine in disaster areas where the infrastructure is destroyed. In this situation, our monitoring system relies on a wireless sensor network (WSN) in ad-hoc mode, which provides a very low data rate. There are several types of real-time traffic to transmit over the low-rate WSN: voice, bio data, and pictures of victims or disaster scenes. First, network quality is judged by the delay of voice packets. Also, priority is given to voice packets over bio data or pictures, because they are critical for telemedicine. Voice packet sampling is performed at intervals of 100ms, because voice packets must arrive at the receiving side in 100ms at least. According to the network quality, one image is segmented in a different size. As a result, real-time voice, bio data & segmented pictures can be transmitted in a low-rate WSN network in 100ms. Furthermore, the health diagnosis center is able to identify the site conditions. Through this study, if the system is applied to a real disaster situation, it will be effectively utilized for rescue activities by rescue workers.

High-quality streaming is getting more popular as it is getting more attention of Internet users. This was possible because there were enough high-speed network infrastructure and Contents Delivery Network (CDN) service. So far, CDN has supported a streaming service by using streaming media cache server that is based on the web cache server as its platform. The static caching is the most popular to the web cache server dealing with the static content. However, the media object of the streaming cache is different from that of the web cache in terms of the size and effective duration. Streaming service requires a large storage space and demands more amount of the traffic. In particular, the traffic of the streaming service is more severely variable due to the faster and more frequent interaction between the client and the server. For these streaming services, CDN uses dynamic caching that can save the cache space and can reduce the response time on the demand of the user. However, the dynamic caching causes the cost of heavy CPU burden. In this paper, we propose a new caching algorithm based on the dynamic caching for streaming media cache servers. The proposed algorithm is a content-based approach to cache an individual content to a server according to the popularity of the content. That is, the contents of high popularity only can be distributed over the multiple cache servers. The experimental results show that the proposed algorithm performs better than conventional approaches in terms of the cache hit rate and the amount of the traffic across the network.

We propose a novel context-aware streaming agent to achieve optimal high quality seamless streaming service in heterogeneous wireless networks and mobile terminals and to utilize high WLAN bandwidth in mobile phones. The major difference between our proposed method and existing methods is the use of mobile terminal oriented context-aware streaming adaptation. We outline a streaming network architecture among the streaming server, gateway, and mobile terminal, an extended RTSP protocol and a streaming quality level selection algorithm in the mobile terminal. We consider vertical handover between HSDPA and 802.11g/n and take advantage of H.264 Scalable Video Coding (SVC). Our new method makes optimal seamless streaming service possible for various network situations, terminal capabilities, and user preferences. Streaming agents first determine adequate quality level based on user preference, terminal constraints, dynamic network conditions and battery status. Then a gateway requests an adequate SVC layer to be sent to the server based on the agent’s requested quality level. Agent and gateway communicate using an extended RTSP protocol which enables content quality modification during streaming. Our novel streaming agent method improves user satisfaction. By selecting an ”optimal network condition” policy, we can improve content and maximize the potential of the 3.28 SVC layer. By minimizing power consumption, we can reduce power consumption by 13% by processing a different SVC layer.

This paper describes a powerful and adaptive spam filtering system for SMS (Short Messaging Service) that uses SVM (Support Vector Machine) and a thesaurus. The system isolates words from sample data using a pre-processing device and integrates meanings of isolated words using a thesaurus, generates features of integrated words through chi-square statistics, and studies these features. The system is realized in a Windows environment and its performance is experimentally confirmed.

IETF suggested MIPv6 and HMIPv6 to provide the mobility support for the IPv6 based environment. HMIPv6 proposed a Mobility Anchor Point to reduce the BU cost caused by the BU process toward the HA. However, HMIPv6 has a problem in the high mobility environment because of the frequent BU processes. This paper proposes a Selective MAP Binding Scheme to reduce the number of unnecessary local BU process in the HMIPv6 based networks where the MN moves at high speed. This scheme has novelty of skipping the local BU process, thereby reducing the total number of local BU and decreasing the power consumption of MN at the same time. We perform OPNET simulations and make a comparison of performance between the proposed scheme and the traditional HMIPv6.

The Stream Control Transmission Protocol (SCTP) is a new transport layer protocol. Multihoming is one of the most important features in SCTP, which can be used by the data sender to send data to a receiver through different paths. Although SCTP provides support for multihoming, the basic reason for such a provision was to improve reliability of associations. Currently, simultaneous transfer of new data to multiple paths is not allowed in SCTP. We can gain significant throughput improvement by simultaneously transferring new data across multiple paths to the receiver. In this paper, the best load sharing using SCTP multihoming is discussed and the techniques are analyzed. In order to achieve load sharing, original congestion control mechanism should be modified to implement load sharing. The new algorithm, split fast retransmission is the key of SCTP load sharing. Finally, through NS-2 simulations we prove that the proposed scheme is effective.

Nowadays, the researches about the IP connectivity for mobile nodeare in progress. In particular, Mobile IP and Hierarchical MobileIP are well-known methods for these researches. In these works,mobile nodes are assumed to be always in the active state whetherthey move to the other cell or not. However, since more than 95\%of mobile nodes are moving in the idle state actually, they shouldchange their states first to the active state for location update.Due to the mentioned problem, it causes the power consumptionextremely. Even though some paging schemes for cellular networkscan solve the waste of power consumption, they don't consider thehigh velocity environment. Therefore, in this paper we propose alow power IP paging scheme with dynamic paging areas where thepaging areas are configured dynamically according to the velocityof the mobile node. The simulation results demonstrate that theproposed IP paging scheme reduces power consumption significantly,as compared to the basic IP paging scheme.

In this paper, we propose a novel anti-collision algorithm for generation 2 RFID system to estimate the number of tags and to use the optimal frame size. Depending on the number of tags, there exists the optimal frame size in the sense that the system efficiency is maximized. The number of tags can be estimated from the collision ratio in terms of collided slots per frame. In addition, we compare our proposed algorithm with other existing schemes by simulation. The proposed scheme is easy to implement, and the simulation results show that its performance improves significantly compared to other schemes in terms of the identification time and the number of consumed slots.

The Stream Control Transport Protocol (SCTP) is a new transport layer protocol that has been designed to provide reliable transport over the Internet. While the Transport Control Protocol (TCP) is the most popular transport protocol for the Internet, it falls short with regard to security, more specifically resilience to Denial-of-Service (DoS) attacks, such as SYN attacks. The need for resilience to DoS attacks is obvious, and SCTP provides for this resilience via its improved handshake mechanism and the Cookie feature. This paper discusses the SCTP simulation with particular emphasis on resilience to DoS attacks. As revealed by our detailed simulation study, the increased DoS resilience comes with increased overheads. While DoS resilience is extremely critical, reducing overheads in the resource-constrained wireless environment also assumes paramount importance. Hence we propose secure SCTP with an innovative Cookie mechanism using a combination of cache and INIT packet repetition to minimize the communication overhead and simultaneously to maximize security associated with SCTP’s DoS resilience for wireless Internet.

This paper describes the design and performance of a secure routing protocol with time-space cryptography for mobile ad-hoc networks. The proposed time-space scheme works in the time domain for key distribution between source and destination as well as in the space domain for intrusion detection along the route between them. For data authentication, it relies on the symmetric key cryptography due to high efficiency and a secret key is distributed using a time difference from the source to the destination. Also, a one-way hash chain is formed on a hop-by-hop basis to prevent a compromised node or an intruder from manipulating the routing information. In order to evaluate the performance of our routing protocol, we compare it with the existing AODV protocol under the same conditions using the ns-2 network simulator. The simulation results show that the proposed protocol provides similar performance in terms of delay and throughput even with the security function

The stream control transport protocol (SCTP) is a new transport layer protocol that has been designed to provide reliable transport over IP networks. While the transmission control protocol (TCP) is the most. popular transport protocol in IP networks, it falls short with regard to security - more specifically, resilience to denial-of-service (DoS) attacks, such as SYN attacks. The need for resilience to DoS attacks is obvious, and SCTP provides for this resilience via its improved handshake mechanism and the cookie feature. The paper discusses SCTP simulation with particular emphasis on resilience to DoS attacks. As revealed by our detailed simulation study, the increased DoS resilience comes with increased overheads. While DoS resilience is extremely critical, reducing overheads in the resource-constrained wireless environment also assumes paramount importance. Hence, we propose an innovative cookie mechanism with a combination of cache and INIT packet repetition to minimize the communication overhead and simultaneously to maximize security associated with SCTP's DoS resilience over mobile ad-hoc networks.

Recently, the Internet-based communication method has been adopted as an open networking solution in the field of remote control and data acquisition. In the current Internet, most networking applications are developed according to the client-server approach. In this paper, we propose an innovative device communication protocol that exchanges the traditional role between client and server to provide a uniform device interface over the Internet. The proposed protocol is implemented as a networking application running on top of the standard TCP/IP protocols. Since the complicated server functionality is excluded from the field devices as a result, their functionality can be minimized as the thin client, thereby making them as small and light as possible in terms of H/W and protocol stack. Moreover, a common Web server is introduced to provide a uniform device interface over the Internet to various client devices. To validate our proposed protocol, we have built a test bed consisting of two types of field devices for security system over the Internet. From these experiments, we ensure that our proposed protocol has been validated, because it works correctly in function and satisfactorily in performance.

This paper describes the design and performance of a new AAL protocol (AAL-UDP) for UDP/IP over wireless ATM networks. The wireless links are characterized by higher error rates and burstier error patterns in comparison with the fiber-based links for which ATM was designed. The purpose of AAL-UDP is to support time-critical UDP traffic over wireless ATM networks. The key ideas in the design consist of no discard at AAL level and header protection with sequence number mechanism. The UDP/IP header is repeated for reliability, because it contains the most important information such as address and port number. The proposed AAL has been validated using a software emulator on the simulated wireless ATM network. The simulation results show that the AAL-UDP provides significant improvement in throughput as well as application level performance compared to the conventional AAL 5 case.

The stream control transport protocol (SCTP) is a new transport layer protocol that has been designed to provide reliable transport over IP networks. While the popular transport control protocol (TCP) is the most widely used protocol in the IP networks and is indeed reliable with a variety of merits, it falls short with regard to the following important aspects: (a) providing for service survivability and (b) security-more specifically, resilience to denial-of-service (DoS) attacks. Service survivability, i.e., providing uninterrupted service amidst random network failures is very important and SCTP helps in this regard via its "multihoming" feature. Likewise, the need for resilience to DoS attacks is obvious, and SCTP also provides for this resilience via its improved handshake mechanism and the cookie features. This paper discusses the modeling and simulation (M&S) of SCTP with particular emphasis on resilience to DoS attacks. Several key M&S aspects with regard to modeling SCTP DoS resilience are presented and discussed. As also revealed by our detailed M&S studies, the increased DoS resilience comes with increased overheads. While DoS resilience is extremely critical, reducing overheads in the resource-constrained wireless environment also assumes paramount importance. Hence we propose an innovative mechanism to significantly reduce the overheads associated with SCTP's DoS resilience.

This paper describes the design and performance of a new ARQ protocol for wireless ATM networks. The wireless channel is characterized by a higher and variable error rate in comparison with fiber-based networks for which ATM was designed. The purpose of the protocol is to provide a capability to dynamically support ATM-based communications in a fluctuating transmission environment by using selective retransmission. The key ideas in the protocol design consist of variable packet size and periodic status message. The packet size is changed adaptively with the optimal size according to the time-varying conditions of the wireless channel, as a result maximizing the throughput efficiency. The proposed protocol has been validated using a software emulator which incorporates a wireless channel model. Experimental performance results based on the implementation are presented.

This paper describes the design and performance of a medium access control protocol (called reservation CSMA/CA) for multimedia traffic over mobile ad-hoc networks. The reservation CSMA/CA protocol is based on a hierarchical approach consisting of two sublayers. The lower sublayer of the MAC protocol provides a fundamental access method using CSMA/CA to support asynchronous data traffic over mobile ad-hoc networks. The upper sublayer is designed to support real-time periodic traffic by making a slot reservation with the three-way handshake prior to actual data transmission. The proposed protocol has been validated using a software emulator which was carried out with the UNIX implementation. The simulation results show that the reservation CSMA/CA offers higher throughput for real-time periodic traffic compared to the IEEE 802.11 standard, while providing deterministic delay performance.