A review of contention resolution algorithms for IEEE 802.14 networks

Bidirectional Cable TV networks using hybrid fiber coaxial (HFC) systems are good examples of broadcast environments where a contention resolution algorithm is needed in order to allocate the multiaccess medium (in this case the upstream link) among the various nodes. Recent activities of the IEEE 802.14 Working Group aimed at defining the physical and medium access control (MAC) layer protocols for HFC cable networks have focused on the study and evaluation of several contention resolution solutions for inclusion in the MAC protocol specifications. In this article several contention resolution algorithms considered by the IEEE 802.14 group are reviewed. Different implementations for several well known contention resolution algorithms such as tree-based and p-persistence are presented. Their performance is evaluated in the HFC context with respect to upstream channel allocation, roundtrip delay, various traffic types, and number of stations in the network. Simulation results for configurations and scenarios of interest are also presented.     

A dynamic control scheme for the IEEE 802.14 draft MAC protocolover CATV/HFC networks

We first describe the draft multiple/random access protocol for IEEE 802.14 over the cable TV/hybrid fiber coaxial (CATV/HFC) networks. To best fit this draft protocol into the target network, we propose a dynamic control scheme to adequately adjust the parameters. Simulations of the draft protocol are then presented to depict the effectiveness of the proposed scheme and further highlight the directions for the design of MAC protocols over the CATV/HFC networks     

HFC网络MAC协议及碰撞解决

ＨＦＣ网络（混合光纤同轴网）采用树状拓扑结构,分布于较广的匹配,有较大的延时,这使得ＨＦＣ网络中的ＭＡＣ（介质访问控制）协议的设计成为一个值得研究的问题。本文对ＨＦＣ网络中几种有影响的ＭＡＣ协议进行了综述,重点介绍了ＩＥＥＥ８０２．１４工作组的８０２．１４草案３。ＨＦＣ网络介质访问控制协议中最有特色的是碰撞解决算法,８０２．１４协 采用ｐ坚持算法结合ｎ叉树算法,前者用于预先避免碰撞而后者用于解决已     

Performance evaluation of candidate MAC protocols for LMCS/LMDSnetworks

Broadband wireless access (BWA) offers attractive features such as ease and speed of deployment, fast realization of revenues, and low infrastructure cost. This paper focuses on medium access control (MAC) alternatives that can find application in an LMDS/LMCS network capable of supporting multimedia traffic. Multifrequency demand assignment TDMA-based schemes appear (at the moment) to be a suitable choice in this context. The selected protocol should be dynamically capable of providing multirate capabilities and quality-of-service guarantees. An obvious candidate for the aforementioned purpose is the LMDS-specific MAC proposal in the DAVIC 1.2 recommendation. For purposes of comparison, we also examine the evolving IEEE 802.14 MAC convergence protocol and MCNS (multimedia cable network system) DOCSIS (ITU J-112) MAC standard that are intended to support similar applications and services in an HFC (hybrid fiber coax) environment. The three protocols are examined under noiseless and noisy channel conditions. Previous results on LMDS channel characteristics are summarized and used for modeling noisy channel conditions. The candidate protocols are compared in terms of mean access delay, throughput, and collision multiplicity statistics, when contention of users is involved. The effect of dynamic slot allocation on the performance of the candidate protocols is also examined     

HFC网络安全与加密机制的研究

增强型基线保密性接口（BPI＋）是一种基于DOCSIS标准的数据保密访问共享媒体的接口标准,利用BPI＋定义的多种密钥及管理协议可以在媒体访问控制层（MAC）解决HFC网络的数据安全问题。这种技术对开展HFC网络数据业务是十分重要的。     

Architecture and performance of a MAC protocol for the HFC system

The IEEE 802.14 standard committee is currently working on a project to find a cost-effective means of providing access to integrated networks for people to enjoy multimedia programs and to work at home. An advanced system based on the cable TV system called hybrid fibre coax (HFC) is being studied. Since some properties of the HFC system preclude the possibility of directly using existing medium access control (MAC) protocols for its data link layer, a MAC scheme based on time division is discussed in this paper. This MAC scheme can be extended for wireless networks. © 1997 John Wiley & Sons, Ltd.     

An investigation into HFC MAC protocols: Mechanisms, implementation, and research issues

This study comprehensively reviews two HFC MAC protocols: Data-Over-Cable Service Interface Specifications (DOCSIS) and IEEE 802.14a. DOCSIS was approved by the ITU as a standard and is supported by many vendors. However, IEEE 802.14a remains a draft due to the delayed standardization process. After briefly introducing the features of HFC networks, the basic operations and mechanisms of these two MAC protocols are then examined. Both standards view an upstream channel as a stream of minislots and have similar mechanisms for upstream bandwidth management, virtual queue, downstream in MPEG-2 format, data-linklayer security, and ranging. However, the standards adopt different mechanisms for upstream access modes, QoS support, and collision resolution. Moreover, the implementation issues over hardware and software design for DOCSIS networks are investigated. This work also identifies the research issues in HFC MAC protocols, particularly allocation and scheduling issues.     

HFC网管系统的VIAC层协议原理与实现

介绍HFC网络设备管理系统的MAC层协议原理及实现。此MAC层协议主要是针对前端控制器（HE）与I类应答器（NE）之间的通信协议，该协议支持在HFC网络的上、下行射频（RF）信道内进行基于“问答式”的消息交换，能进行多种类型网络协议PDU的传送（包括基于串行协议的IP包和SNMP包），以前端控制器（HE）为中心来管理应答器（NE）的方式，有效地利用了HFC网络上、下行RF信道的频谱资源。     

PCUP: pipelined cyclic upstream protocol over hybrid fiber coax

In order to bring the NII (National Information Infrastructure) into the home, the community cable TV networks have to be reengineered to support two-way interactive services. The authors propose the PCUP (pipelined cyclic upstream protocol) as the upstream MAC (medium access control) protocol for the HFC (hybrid fiber coax) community access network. The PCUP is designed with the intention of pipelining the upstream channel. This is achieved by proper station positioning, which measures the station propagation offset from the headend, and transmission scheduling which assigns each station a transmission starting time and duration in a cycle. By taking into account the propagation offsets and transmission lines, transmitted cells can appear back-to-back (i.e., pipelined) at the headend. Since only the active stations are scheduled to transmit in a cycle, a membership control mechanism, which runs a contention-based tree walk algorithm, is executed periodically to allow the stations to join or leave. The authors also compare the PCUP with various schemes proposed to the IEEE 802.14 committee     

Network management for residential broadband interactive dataservices

Although coaxial networks and hybrid fiber coaxial (HFC) networks have been in use for delivering television programs to the home, their usage as access networks to provide broadband interactive data services (BIDS) to the home is very recent. In this article, the authors highlight the importance of managing the networking infrastructure for BIDS and explore the unique requirements and challenges in managing HFC networks. Considering the operational requirements of BIDS operators, network maintenance, subscriber support, and planning are identified as the three functional areas that a BIDS network management system must address. It is argued that management support built into BIDS equipment (e.g., cable modems, headend cable termination units, subscriber PCs) can provide a cost-effective way of monitoring the status and performance of HFC networks, and some initial experiences of implementing and deploying network monitors in a real-world BIDS system are presented     

Network architecture and medium access control for deploying third generation (3G) wireless systems over CATV networks

We propose a novel and cost‐effective approach for the deployment of third generation (3G) wireless systems over hybrid fiber coaxial (HFC) CATV networks. The main goal is to facilitate 3G deployment over the existing CATV plant and reduce the large cost required for building a dedicated last mile infrastructure for 3G access networks. Our proposal reduces the last mile cost by sharing the existing CATV network and using the standard equipment and protocols of data‐over‐cable systems interface specifications (DOCSIS). This allows rapid deployment of 3G wireless systems, facilitates convergence of wireless and wireline networks and paves the way towards all IP wireless networks. Enhancements to the DOCSIS medium access control (MAC) protocol must be implemented in order to support Quality of Service (QoS) guarantees for 3G data and signaling traffic. This paper presents the proposed 3G over CATV network architecture and DOCSIS medium access control (MAC) enhancements for enabling the support of QoS guarantees for 3G data and signaling traffic. The proposed MAC enhancements can reduce the access delay for delay‐sensitive traffic by 30 to 40% over existing DOCSIS MAC without compromising QoS guarantees for other traffic classes, or the DOCSIS channel utilization. Copyright © 2004 John Wiley & Sons, Ltd.     

Efficient protocols for multimedia streams on WDMA networks

This paper introduces a new approach to integrate different types of medium access control (MAC) protocols into a single wavelength-division-multiplexing (WDM) network system. The WDM network is based on a passive star coupler, and the purpose of integrating different MAC protocols is to efficiently accommodate various types of multimedia traffic streams with different characteristics and quality of service demands. Our integrated MAC protocol is termed multimedia wavelength-division multiple-access (M-WDMA). Three types of multimedia traffic streams are considered in this paper: constant-bit-rate traffic and two classes of variable-bit-rate traffic. Accordingly, three tunable transmitters and one fixed home channel receiver are used in the design of each WDM node. The transmitters transmit the three types of multimedia traffic streams in a pipeline fashion so as to overcome the tuning time overhead and to support parallel transmissions of traffic streams that emerge simultaneously. We further incorporate a dynamic bandwidth allocation scheme that dynamically adjusts the portions of bandwidth occupied by the three types of traffic streams according to their demands. Consequently the M-WDMA protocol achieves high utilization and efficiently adapts to the demands of the multimedia streams so as to guarantee their QoS. The performance of the M-WDMA is evaluated through a simple analytical model and extensive discrete-event simulations. It is shown that the M-WDMA can satisfy the QoS requirements of various mixes of multimedia traffic streams even under very stringent requirements. Moreover, we show that the M-WDMA outperforms conventional MAC protocols for WDM networks. As a result, we expect M-WDMA to be a good multimedia MAC candidate protocol for future-generation WDM networks.     

应用流量管理技术在有线宽频网络中的应用

有线宽频网络运营商在网络运营中，会因为应用流量的不规范应用而对业务造成极大影响甚至带来损失，探讨把应用流量管理技术引进有线宽带网络，通过该技术对应用流量的智能识别、分类、控制等实现对网络流量的管理，进一步提高带宽资源的利用率。     

利用HFC接入Internet的MAC层协议设计与分析

分析了HFC网络实现双向数据传输的结构,分析比较了802.14/DOCSIS规范,提出使用扩频技术可以获得稳固的传输特性,就S＿CDMA多址接入方式和M＿ary CDMA方式分别设计了Internet接入的MAC层协议-竞争/冲突解决和轮询机制,分析表明该协议简单有效,易于实现。     

Medium access protocol design for delay-guaranteed multicode CDMA multimedia networks

To enable multimedia real-time applications over next-generation wireless code-division multiple access (CDMA) packet-switching networks, previous efforts show a proper scheduling policy is the key to provide delay-guaranteed access services to various traffic types with different bit error rate (BER) requirements. Considering the support of the prevailing Internet protocol (IP) with variable-length packets in future mobile networks, we develop a mathematically delay-optimal medium access control (MAC) protocol over multicode CDMA (MC-CDMA) environments under the continuous-time assumption. From our investigations, we suggest that a good MAC protocol should be designed by using a proper single-server scheduling policy to guarantee packet-delay, and controlling the maximal number of simultaneous spreading-code transmissions to maintain the required BER. We further evaluate the performance of some MC-CDMA MAC protocols supporting QoS on BER and packet-delay, and show that MAC schemes conforming to our design rules give better performance on packet-delay when maintaining acceptable BER of various traffic types.     

A dynamic bandwidth allocation scheme for differentiated services in EPONs

Passive optical networks bring high-speed broadband access via fiber to the business, curb and home. Among various types of PONs, Ethernet PONs are gaining more and more attention since they are built on widely used Ethernet technology and can offer high bandwidth, low cost and broad services. EPONs use a point-to-multipoint topology, in which multiple optical network units share one uplink channel to transmit multimedia traffic to a control element, the optical line terminal. To avoid data collision on the shared uplink channel, a key issue in EPONs is a contention-free MAC protocol for the OLT to schedule the transmission order of different ONUs. In this article we first review some DBA schemes available in the literature, then propose a two-layer bandwidth allocation scheme that implements weight based priority for this need. To maximally satisfy the requests of all ONUs and provide differentiated services, an ONU is allowed to request bandwidth for all its available traffic, and all traffic classes proportionally share the bandwidth based on their instantaneous demands. The weight set for each class not only prevents high-priority traffic from monopolizing the bandwidth under heavy load but also ensures a minimum bandwidth allocated to each traffic class.     

基于HFC的宽带接入网关键技术

随着通信的发展和“信息高速公路”概念的提出,网络运营商越来越倾向集视频、话音、数据于一体的宽带综合业务,如今世界各国相继开发了基于现有铜缆的接入网技术高比特率数字用户环路(HDSL)和不对称数字用户环路(ADSL)、基于光缆接入技术的光接入网(OAN)、混合光纤同轴电缆(HFC)网络以及无线接入技术等宽带用户接入网技术,文章详细分析了HFC宽带接入网的网络结构及其关键技术。     

Dynamic resource allocation for quality of service on a PON withhome networks

Earlier efforts on optical access concentrated on the design of PONs for the collection and distribution portion of the access network. A possible evolution scenario for these types of access networks could be the SuperPON system. The SuperPON system exploits all possible upgrades of an FSAN APON system. In these networks the optical hardware is very simple, but a media access control protocol is needed for upstream traffic control. Even so, the role of communications is already well established in the office environment, thanks to networking innovations such as the Ethernet LAN. With the development of cheap, affordable broadband communications and the increasing complexity of consumer goods, it seems natural to extend the network into homes. As home area network application ever increases, we consider connectivity between the access network and the home network, which generates multiple traffic, in order to design a MAC protocol over the SuperPON access network with home networks. Global FIFO is quite simple, and allows dynamic upstream bandwidth allocation on the basis of a request-and-permit mechanism on the APON architecture. It has good bandwidth efficiency; however, being cell-based, it does not consider multiple traffic types from home networks. In this article we describe and analyze a new dynamic MAC resource allocation algorithm called multiple queue-FIFO that can achieve good performance under the SuperPON access network in the home network environment     

Multimedia-MAC protocol: its performance analysis and applications for WDM networks

The design of the medium-access control (MAC) protocol is the most crucial aspect for high-speed and high-performance local and metropolitan area networks, since the decisions made at this level determine the major functional characteristics of these networks. Most of the MAC protocols proposed in the literature are not suitable for multimedia applications, since they have been designed with one generic traffic type in mind. As a result, they perform quite well for the traffic types they have been designed for, but poorly for other traffic streams with different characteristics. In this paper, we propose an integrated MAC protocol called the Multimedia-MAC (M-MAC), which integrates different MAC protocols into a hybrid protocol in a shared-medium network to efficiently accommodate various types of multimedia traffic streams with different characteristics and quality-of-service demands, namely, a constant-bit-rate traffic, bursty traffic (say, variable-bit-rate traffic), and emergency messages (say, control messages). We have developed a mathematical framework for the analysis and performance evaluation of our M-MAC protocol, which involves a queueing system with vacation. We have applied our M-MAC design approach to a wavelength-division multiplexing network, and evaluated its performance under various traffic conditions.     

Multimedia—MAC Protocol: Its Performance Analysis and Applications for WDM Networks

Multimedia—MAC Protocol: Its Performance Analysis and Applications for WDM Networks The design of the Medium Access Control (MAC) protocol is the most crucial aspect for high-speed and high-performance Local and Metropolitan Area Networks (LANs/MAN's) since the decisions made at this level determines the major functional characteristics of these networks. Most of the MAC protocols proposed in literature are not suitable for multimedia applications since they have been designed with one generic traffic type in mind. As a result, they perform quite well for the traffic types they have been designed for, but poorly for other traffic streams with different characteristics. In this paper, we propose an integrated MAC protocol (herein termed as Multimedia Medium Access Control protocol (Multimedia -MAC) which integrates different MAC protocols into a hybrid protocol in a shared medium network to efficiently accommodate various types of multimedia traffic streams with different characteristics and QoS demands, namely, a constant-bit-rate (CBR) traffic, bursty traffic (say, variable-bit-rate (VBR) traffic) and emergency messages (say, control messages). We have developed a mathematical framework for the analysis and performance evaluation of our Multimedia-MAC protocol which involves a queueing system with vacation. We have applied our Multimedia-MAC design approach to a wavelength division multiplexing (WDM) network and evaluated its performance under various traffic conditions.