5G移动网络中关键通信技术的演进

阐述了基于5G移动网络网络切片技术的关键通信技术演进,基于B-TrunC标准和3GPP宽带关键通信标准,构建了独立建网模式和结合公网模式两种宽带关键通信网络的演进模式,分析和比较了各种组网模式性能,最后提出了基于宽窄带融合、逐步过渡的演进方式,实现现有窄带专业通信网络向宽带关键通信网络的演进。     

微纳卫星组网星间链路设计及关键技术分析

微纳卫星组网应用可大幅度提高航天装备的能力,较单颗大卫星具有明显的优势。首先,介绍了国内外微纳卫星组网的研究情况,以组网侦察应用为例分析了星间测量与通信链路的技术需求,并进行了系统架构和体制设计;其次,在星座设计基础上开展系统仿真,并提出了一体化设备实现方案;最后,分析了微纳卫星组网系统中几项重要的关键技术及其解决方案,对系统的设计和工程实现具有参考价值。     

Toward manageable middleboxes in software‐defined networking

Software‐defined networking (SDN) acts as a centralized management unit, especially in a network with devices that operate under the transport layer of the OSI model. However, when a network with layer 7 middleboxes (MBs) is considered, current SDNs exhibit limitations. As such, to achieve a real‐centralized management unit, a new architecture is required that decouples the data and control planes of all network devices. In this report, we propose such a complementary architecture to the current SDN in which SDN‐enabled MBs are included along with contemporary SDN‐enabled switches. The management unit of this architecture improves network performance and reduces routing cost by considering the status of the MBs during flow forwarding. This unit consists of the following two parts: an SDN controller (SDNC) and a middlebox controller (MBC). The latter selects the best MBs for each flow and the former determines the best path according to its routing algorithm and provides information via the MBC. The results show that the proposed architecture improved performance because the utilization of all network devices including MBs is manageable.     

Incentive edge caching in software‐defined internet of vehicles: A Stackelberg game approach

In this paper, we investigate an incentive edge caching mechanism for an internet of vehicles (IoV) system based on the paradigm of software‐defined networking (SDN). We start by proposing a distributed SDN‐based IoV architecture. Then, based on this architecture, we focus on the economic side of caching by considering competitive cache‐enablers market composed of one content provider (CP) and multiple mobile network operators (MNOs). Each MNO manages a set of cache‐enabled small base stations (SBS). The CP incites the MNOs to store its popular contents in cache‐enabled SBSs with highest access probability to enhance the satisfaction of its users. By leasing their cache‐enabled SBSs, the MNOs aim to make more monetary profit. We formulate the interaction between the CP and the MNOs, using a Stackelberg game, where the CP acts first as the leader by announcing the popular content quantity that it which to cache and fixing the caching popularity threshold, a minimum access probability under it a content cannot be cached. Then, MNOs act subsequently as followers responding by the content quantity they accept to cache and the corresponding caching price. A noncooperative subgame is formulated to model the competition between the followers on the CP's limited content quantity. We analyze the leader and the follower's optimization problems, and we prove the Stackelberg equilibrium (SE). Simulation results show that our game‐based incentive caching model achieves optimal utilities and outperforms other incentive caching mechanisms with monopoly cache‐enablers whilst enhancing 30% of the user's satisfaction and reducing the caching cost.     

SYN‐Guard: An effective counter for SYN flooding attack in software‐defined networking

In software‐defined networking (SDN), TCP SYN flooding attack is considered as one of the most effective attacks to perform control plane and target server saturation. In this attack, an attacker generates a large number of malicious SYN requests, and because of the absence of the forwarding rules, the data plane switches have to forward these SYN messages to the controller. This excessive forwarding causes congestion over the communication channel between a data plane and control plane, and it also exhausts computational resources at both the planes. In this paper, we propose a novel countermeasure called SYN‐Guard to detect and prevent SYN flooding in SDN networks. We fully implement SYN‐Guard on the SDN controller to validate the incoming TCP connection requests. The controller installs forwarding rules for the SYN requests that successfully clear the validation test of SYN‐Guard. The host of the fake SYN request is detected, and SYN‐Guard prevents it from sending any further SYN requests to the data plane switch. The performance evaluation done using the simulation results shows that SYN‐Guard exhibits low side effect for genuine TCP requests, and when compared with standard SDN and state‐of‐art proposals, it reduces the average response time up to 21% during an ongoing SYN flooding attack.     

Analytical characterization of cache replacement policy impact on content delivery time in information‐centric networks

Information‐centric networking (ICN) has emerged as a promising candidate for designing content‐based future Internet paradigms. ICN increases the utilization of a network through location‐independent content naming and in‐network content caching. In routers, cache replacement policy determines which content to be replaced in the case of cache free space shortage. Thus, it has a direct influence on user experience, especially content delivery time. Meanwhile, content can be provided from different locations simultaneously because of the multi‐source property of the content in ICN. To the best of our knowledge, no work has yet studied the impact of cache replacement policy on the content delivery time considering multi‐source content delivery in ICN, an issue addressed in this paper. As our contribution, we analytically quantify the average content delivery time when different cache replacement policies, namely, least recently used (LRU) and random replacement (RR) policy, are employed. As an impressive result, we report the superiority of these policies in term of the popularity distribution of contents. The expected content delivery time in a supposed network topology was studied by both theoretical and experimental method. On the basis of the obtained results, some interesting findings of the performance of used cache replacement policies are provided.     

面向无人装置协同操作的安全认证协议

无人装置协同操作动态组网需要安全的群组通信。依据无线环境中的不同安全域,提出了一种具有身份保护的安全组网协议。该协议采用基于身份的匿名签名算法设计了安全组网机制,实现了传感器节点、作动器节点、密钥分发中心和控制台的四方安全认证和密钥交换,并为安全域内的无人操作装置建立了安全传输通道;采用匿名身份认证与可追溯机制相结合的方式,构建了无人操作装置间动态组网和数据安全传输,以为协同操作提供实时、安全的数据通道,实现无人操作装置在传感器和作动器级的协同。     

面向协议无感知转发技术的SDN试验床

基于OpenFlow的软件定义网络(SDN)中的转发设备不便于支持新协议的转发,因此协议无感知转发(Protocol Oblivious Forwarding,POF)技术被提出.本文基于POF技术和OpenFlow控制器POX,设计并实现了一种支持POF技术的SDN控制器,POF控制器可以充分利用POF转发设备并且体现了SDN的可编程性.同时,我们基于POF控制器搭建了POF试验床,实验结果表明POF控制器能够有效地管理POF网络,并提供高效的控制功能.     

“Masculine Guys Only”: The effects of femmephobic mobile dating application profiles on partner selection for men who have sex with men

Mobile dating applications (apps) have changed the way gay men find others in their geographic area for sexual activity and romantic relationships. Many of these apps are branded in relation to traditional masculinity and have become a breeding ground for femmephobic, or anti-effeminate, language. Past research has not examined the effects of femmephobic language in social networking apps designed for men who have sex with men (MSM) on app users' perceptions. This research employed an online experiment of 143 MSM app users to test how users respond to femmephobic and non-femmephobic language use in MSM dating profiles. Participants rated the profile users, as well as reported their desire to meet the user in an offline context. Results indicated that the use of femmephobic language in dating profiles affects a potential partner's perceived intelligence, sexual confidence, and dateability, as well as one's desire to meet potential partners offline for friendship or romantic purposes. Anti-effeminacy was an important moderator of the main effect.     

The Effects of Social Networking Sites on Consumer–Brand Relationships

In the era of a vastly changing marketing communications environment, social media and social networking sites (SNS) have become an attractive outlet for brand promotions and advertising. As traditional media such as television, radio, and newspapers prove ineffective in establishing a valuable rapport with consumers, it is social networks which are expected to build bonds and engage online users into an amusing dialog, play, and intercourse with brands. This study applies an experimental design to assess the effects of SNS on the relationship between brands and consumers. Customer-based brand equity is adopted in this study as a reflective measure of consumer–brand connection. In order to evaluate hypothesized interactions, the linear mixed effects models are used. The results show very little (if any) impact of SNS on brand equity. Relevant explanations are discussed and further research directions are indicated.