ATM技术在广州市电信局计算机专用网的应用

本文介绍了利用ＡＴＭ技术进行组网的原理和广州市电信局计算机专用网的建设情况，并从应用的角度分析了这种网方式的该局带来的效益。     

A journey through the DQDB network literature

The Distributed Queue Dual Bus (DQDB) network has been adopted as the subnetwork for the IEEE 802.6 metropolitan area network (MAN) standard. Since its original proposition a few years back, DQDB has attracted significant attention because of the simplicity of its medium access control (MAC) protocol. The intense scrutiny that DQDB has been subjected to has lead to the identification of a number of its potential problems, and a number of “add-on” strategies have been proposed to “fix” such problems. Moreover, a number of architectural variations have also been proposed to improve the network behavior. Since there has been a literature explosion on DQDB over the past few years, this article is intended to extract the significant features of various DQDB-based investigations, and to present them in an unified manner.     

光缆交接箱在城域网建设中的应用

针对目前城域网建设中存在的问题，介绍光缆交接箱的原理、功能以及在城域网建设中的应用。     

Physical Frame Time-Slot Technique Switching- A New Switching over DWDM

A novel technique called physical frame time-slot switching （PFTS） is discussed and its technical and application aspects are analyzed. The format of the ethernet media access control （MAC） frame is borrowed in defining the physical frame for PFTS and the transmission time for the maximum size of the MAC frame is defined as a physical frame time-slot （PFT）. Consequently, user data can be fed into PFTS and switched in a single layer sub-network in an asynchronous mode.     

Acid‐Responsive Transferrin Dissociation and GLUT Mediated Exocytosis for Increased Blood–Brain Barrier Transcytosis and Programmed Glioma Targeting Delivery

Receptor mediated transcytosis (RMT) is a common mechanism used for nanotherapeutics to traverse the blood–brain barrier (BBB). However, the transcytosis of ligand modified nanoparticles via RMT is likely to be trapped within brain capillary endothelial cells due to the high binding affinity of ligand with receptors, which greatly reduces the amount of nanoparticles across BBB. Here, P‐aminophenyl‐α‐D‐mannopyranoside (MAN) decorated doxorubicin‐loaded dendrigraft poly‐l‐lysine with acid‐cleavable transferrin (Tf) coating outside (DD‐MCT) is proposed. The DD‐MCT is engineered to specifically recognize the Tf receptor (TfR) on the luminal side of BBB endothelium. Then the DD‐MCT undergoes an acid‐responsive cleavage of Tf, leading to the separation of MAN‐decorated DGL‐DOX (DD‐M) from the Tf–TfR complex in endo/lysosomes. The detached DD‐M is more prone to escape from endo/lysosomes and can further be exocytosed into brain parenchyma via the mediation of glucose transporter located on the abluminal endothelial membrane. Moreover, the DD‐M in brain parenchyma can target glioma cells. Significantly, the DD‐MCT enters into brain parenchyma in greater amounts, resulting in enhanced accumulation at glioma site and thus improved antiglioma therapeutic outcome. This strategy pioneers a new path for reducing the trapping of nanotherapeutics within BBB endothelium but increasing their transcytosis into brain parenchyma.     

基于“IPv6+”的5G承载网切片技术与应用

5G承载网切片技术是满足5G业务,特别是垂直行业场景对差异化服务质量保证需求的基础。对如何在网络基础设施层、网络切片实例层以及网络切片管理层将“IPv6+”关键技术与承载网切片结合使用进行了研究。以北京联通为例,介绍了智能城域网向基于“IPv6+”的承载网切片演进的演进目标、应用场景、演进计划以及存在的问题与建议。     

10Gbit／s以太网技术探析及应用前景

在城域网中,由于以太网技术更加适应业务流量急剧分组化的趋势,可以为用户提供容量、便利性以及成本方面的优势,而且随着以太网传送技术在保护恢复、服务质量保证等能力上的增强,业界开始将以太网向城域网和广域网进行扩展,而10Gbit／s以太网正是以太网突破传统局域网向城域网和广域网延伸的关键技术。     

宽带城域网的无线接入

文章对城域网及宽带无线接入的基本概念作了介绍,对宽带无线接入的不同技术方式进行了分析和比较,讨论了本地多点分配业务系统和其它无线接入技术在宽带城域网应用中需要关注的关键问题——无线接入的网络管理、调制方式和接入协议,重点讨论了无线接入网的安全问题。     

云网融合场景下的传输网络架构探讨

在本地传输网架构基础上,根据云网融合场景下云间互联、电信云、政企及个人云业务场景对传输网络提出的要求,推演出传输网络的目标架构演进方向.在此基础上,以面向云网融合的新型城域网建设案例进行印证,提出建成一张家宽+5G承载+政企统一承载的目标网新平面,并采用叶脊架构、智能传输网(Smart Transport Networ...     

城域宽带网的发展策略

本文分析了发展城域宽带网涉及到的一些主要技术，重点阐述了电信运营商建设城域宽带网的基本策略。