WIMAX Basics from PHY Layer to Scheduling and Multicasting Approaches

WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wireless technology for providing Last mile solutions for supporting higher bandwidth and multiple service classes with various quality of service requirement. The unique architecture of the WiMAX MAC and PHY layers that uses OFDMA to allocate multiple channels with different modulation schema and multiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. The main architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multi hop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS (Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditions adaptations and supporting QoS for classes of services is the key points in scheduling, admission control or multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hop routes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) or to Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas based on scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMP and Mesh deployments from main physical layers features with differentiation of MAC layer features to scheduling and multicasting approaches in both modes of operations

IP and ATM integration: A New paradigm in multi-service internetworking

ATM is a widespread technology adopted by many to support advanced data communication, in particular efficient Internet services provision. The expected challenges of multimedia communication together with the increasing massive utilization of IP-based applications urgently require redesign of networking solutions in terms of both new functionalities and enhanced performance. However, the networking context is affected by so many changes, and to some extent chaotic growth, that any approach based on a structured and complex top-down architecture is unlikely to be applicable. Instead, an approach based on finding out the best match between realistic service requirements and the pragmatic, intelligent use of technical opportunities made available by the product market seems more appropriate. By following this approach, innovations and improvements can be introduced at different times, not necessarily complying with each other according to a coherent overall design. With the aim of pursuing feasible innovations in the different networking aspects, we look at both IP and ATM internetworking in order to investigating a few of the most crucial topics/ issues related to the IP and ATM integration perspective. This research would also address various means of internetworking the Internet Protocol (IP) and Asynchronous Transfer Mode (ATM) with an objective of identifying the best possible means of delivering Quality of Service (QoS) requirements for multi-service applications, exploiting the meritorious features that IP and ATM have to offer. Although IP and ATM often have been viewed as competitors, their complementary strengths and limitations from a natural alliance that combines the best aspects of both the technologies. For instance, one limitation of ATM networks has been the relatively large gap between the speed of the network paths and the control operations needed to configure those data paths to meet changing user needs. IP\u27s greatest strength, on the other hand, is the inherent flexibility and its capacity to adapt rapidly to changing conditions. These complementary strengths and limitations make it natural to combine IP with ATM to obtain the best that each has to offer. Over time many models and architectures have evolved for IP/ATM internetworking and they have impacted the fundamental thinking in internetworking IP and ATM. These technologies, architectures, models and implementations will be reviewed in greater detail in addressing possible issues in integrating these architectures s in a multi-service, enterprise network. The objective being to make recommendations as to the best means of interworking the two in exploiting the salient features of one another to provide a faster, reliable, scalable, robust, QoS aware network in the most economical manner. How IP will be carried over ATM when a commercial worldwide ATM network is deployed is not addressed and the details of such a network still remain in a state of flux to specify anything concrete. Our research findings culminated with a strong recommendation that the best model to adopt, in light of the impending integrated service requirements of future multi-service environments, is an ATM core with IP at the edges to realize the best of both technologies in delivering QoS guarantees in a seamless manner to any node in the enterprise

Internet Protocol (IP) Multicast: Final Report

Report presents the results of the Institute for Simulation and Training\u27s implementation and integration of new protocols into the Testbed for Research in Distributed Interactive Simulation (TRDIS) testbed, especially the Internet Protocol (IP) Multicast (IPmc) and Internet Group Management Protocol network protocols, into a simulation application

Satellite Networks: Architectures, Applications, and Technologies

Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled

Implications of Implementing HDTV Over Digital Subscriber Line Networks

This thesis addresses the different challenges a telecommunications company would face when trying to implement an HDTV video service over a Digital Subscriber Line (DSL) connection. Each challenge is discussed in detail and a technology, protocol, or method is suggested to overcome that particular challenge. One of the biggest challenges is creating a network architecture that can provide enough bandwidth to support video over a network that was originally designed for voice traffic. The majority of the network connections to a customer premises in a telephony network consists of a copper pair. This type of connection is not optimal for high bandwidth services. This limitation can be overcome using Gigabit Ethernet (GE) over fiber in the core part of the network and VDSL2 in the access part of the network. For the purposes of this document, the core portion of the network is considered to be an area equal to several counties or approximately 50 miles in radius. The core network starts at the primary central office (CO) and spreads out to central offices in suburbs and small towns. The primary central office is a central point in the telecom operator\u27s network. Large trunks are propagated from the primary central office to smaller central offices making up the core network. The access portion of the network is considered to be an area within a suburb or small town from the central office to a subscriber\u27s home. Appendix A, located on page 60, contains a network diagram illustrating the scope of each of the different portions of the network. Considerations must also be given for the internal network to the residence such as category 5 (Cat5) cable or higher grade and network equipment that can provide up to 30 Megabits per second (Mbps) connections or throughput. The equipment in the telecommunications network also plays a part in meeting the challenge of 30 Mbps bandwidth. GE switches should be used with single mode fiber optic cable in the core part of the network. Digital Subscriber Line Access Multiplexers (DSLAM) with the capability to filter Internet Group Management Protocol (IGMP) messages should be used in the access part of the network to facilitate bandwidth utilization. Placement of this equipment and how the data is aggregated is another issue to consider when implementing HDTV service. Another major challenge facing the implementation of HDTV over DSL networks is controlling quality of service (QoS) throughout the network. Class of Service (CoS) and Differentiated Services (DiffServ) is a method of QoS that would enable video packets to have a higher priority and less delay than other data packets. The consumer could have data, video, and voice traffic all over the same DSL connection. Data, video and voice packets would need to have a different priority in order to maintain appropriate QoS levels for each service. The use of advanced technology in video encoding will be essential to the success of the video service. MPEG-2, MPEG-4, and Windows Media 9 are just a few of the video encoding technologies that could be used to reduce the necessary bandwidth for HDTV. The advancement of this technology is essential to allow telecommunications providers to offer HDTV. Another challenge for the telecom operator concerns the security of the network and service after implementation. Theft of service will be another area that the telecomm operator will be forced to resolve. The cable operators currently face this issue and lose millions of dollars in revenue. Authentication, IP filtering and MAC address blocking are a few possible solutions to this problem

Saturation routing for asynchronous transfer mode (ATM) networks

The main objective of this thesis is to show that saturation routing, often in the past considered inefficient, can in fact be a viable approach to use in many important applications and services over an Asynchronous Transfer Mode (ATM) network. For other applications and services, a hybrid approach (one that partially uses saturation routing) is presented. First, the minimum effects of saturation routing are demonstrated by showing that the ratio, defined as f, of routing overhead cells over information cells is small even for large networks. Second, modeling and simulation and M/D/l queuing analysis techniques are used to show that the overall effect on performance when using saturation routing is not significant over ATM networks. Then saturation routing ATM implementation is also provided, with important extensions to services such as multicast routing. After an analytical comparison, in terms of routing overhead, is made between Saturation Routing and the currently proposed Private Network-Network Interface (PNNI) procedure for ATM routing made by the ATM forum. This comparison is made for networks of different sizes (343node and 2401 -node networks) and different number of hierarchical levels (3 and 4 levels of hierarchy). The results show that the higher the number of levels of hierarchy and the farthest (in terms of hierarchical levels) the source and the destination nodes are from each other, the more advantageous saturation routing becomes. Finally, a set of measures of performance for use by saturation routing (or any routing algorithm), as metrics for routing path selection, is proposed. Among these measures, an innovative new measure of performance derived for measuring quality of service provided to Constant Bit Rate (CBR) users (e.g., such as voice and video users) called the Burst Voice Arrival Lag (BVAL) is described and derived

Dynamic Buffer Management for Multimedia QoS in Beyond 3G Wireless Networks

This paper investigates a dynamic buffer management scheme for QoS control of multimedia services in beyond 3G wireless systems. The scheme is studied in the context of the state-of-the-art 3.5G system i.e. the High Speed Downlink Packet Access (HSDPA) which enhances 3G UMTS to support high-speed packet switched services. Unlike earlier systems, UMTS-evolved systems from HSDPA and beyond incorporate mechanisms such as packet scheduling and HARQ in the base station necessitating data buffering at the air interface. This introduces a potential bottleneck to end-to-end communication. Hence, buffer management at the air interface is crucial for end-to-end QoS support of multimedia services with multiplexed parallel diverse flows such as video and data in the same end-user session. The dynamic buffer management scheme for HSDPA multimedia sessions with aggregated real-time and non real-time flows is investigated via extensive HSDPA simulations. The impact of the scheme on end-to-end traffic performance is evaluated with an example multimedia session comprising a real-time streaming flow concurrent with TCP-based non real-time flow. Results demonstrate that the scheme can guarantee the end-to-end QoS of the real-time streaming flow, whilst simultaneously protecting the non real-time flow from starvation resulting in improved end-to-end throughput performance

Netzwerkmanagement und Hochgeschwindigkeitskommunikation. Teil XIV

Der Interne Bericht enthaelt die Beitraege zum Seminar "Netzwerk-Management und Hochgeschwindigkeits-Kommunikation" des Instituts fuer Telematik (Prof. Dr. Dr. h.c. G. Krueger),das im Sommersemester 1996 zum 14. Mal stattgefunden hat. Die Themenauswahl kann grob in folgende fuenf Bloecke gegliedert werden: 1 - Ein Block ist dem Management von Netzen gewidmet. Hier werden zum einen allgemeine Ansaetze wie TMN und TINA vorgestellt und der Einsatz objektorientierter Techniken im Management diskutiert. Zum anderen finden sich Beitraege zum Management in ATM-Netzen. Themen sind hier das LMI, Aspekte des Accounting sowie das Fehler- und Leistungsmanagement in ATM. 2 - Ein zweiter Block beschaeftigt sich mit Fragen im Zusammenhang von Multicast in ATM-Netzen. Hier werden der Mechanismus der Adressaufloesung mittels des MARS-Konzepts sowie die reihenfolgetreue Auslieferung in Multicast-Gruppen diskutiert. 3 - Ein weiteres Thema ist ein Vergleich aktueller Authentisierungs- und Zertifizierungssysteme und liegt damit im Bereich der Sicherheit von Systemen. 4 - Der vierte Themenbereich des Seminars beschaeftigt sich mit dem ATM-Adaptionsschichtprotokoll SSCOP, das oft zur Unterstuetzung von Signalisierungsmechanismen wie denen des Q.2931 eingesetzt wird. 5 - Schliesslich werden noch Aspekte verteilter Simulationen betrachtet

The design and analysis of a corporate data network supporting a real-time clinical data application

In this study a design is proposed for a corporate, data network supporting real-time data applications. The proposed network incorporates both Local Area Network and Wide Area Network technologies to form a system capable of supporting a variety of applications. Multimedia software, like desktop video conferencing, IP telephony, and video streaming are becoming more pervasive. Since multimedia applications depend on active human involvement and perception, they are commonly referred to as real-time. The content of real-time applications relies on the timely and consistent delivery of information. If real-time applications experience any variation in information delivery, usually referred to as jitter, the result is unacceptable application performance. However, real-time applications are not solely limited to traditional multimedia. Interactive client-server based data applications also fall into this category. This project will specifically focus on the performance of a real-time clinical application, which has become predominant in the healthcare industry. To support the implementation of the proposed network, empirical data was gathered from system testing. Testing involved comparing the performance of a real-time application on the proposed design, against the current architecture. The result found that the proposed data network design reduced transport latency, allowing the real-time application to perform more efficiently

ATM-kytkinpiirisarja liityntäsolmussa

Tämän diplomityön tarkoituksena oli tutkia kuinka kaupallinen ATM-kytkinpiirisarja saadaan sovitettua osaksi ATM-verkon liityntäsolmun arkkitehtuuria sekä rakentaa evaluointisysteemi yhden tällaisen arkkitehtuurin testaamiseksi. Tässä diplomityössä liityntäsolmu on määritelty verkkoelementiksi, joka yhdistää loppukäyttäjät verkkoon. Se kerää dataa, mitä tahansa digitaalista dataa, käyttäjiltä ja välittää sen verkkoon. Se voi myös toimia ATM-kytkin tai ATM-ristikytkentäelementtinä. Tämä tarkoittaa sitä, että liityntöjä verkkoon voi olla useampia kuin yksi ja liityntäsolmu pystyy kytkemään dataa niiden välillä samaan tapaan kuin käyttäjäliityntöjen välilläkin. Käyttäjäliitynnät voivat olla esimerkiksi johonkin DSL-tekniikkaan perustuvia liityntöjä, E1/T1-liityntöjä tai POTS-liityntöjä. Eräs mahdollisuus liityntäsolmun arkkitehtuurin toteuttamiseksi on käyttää kaupallista kytkinpiirisarjaa. Markkinoilla on monia vaihtoehtoja tähän tarkoitukseen. Tässä diplomityössä on vertailututkimus kolmen eri kytkinpiirisarjan sopivuudesta tähän tarkoitukseen. IDT SWITCHStAR[TM ] kytkinpiirisarjaan tutustutaan lähemmin suunnittelemalla ja rakentamalle sille erityinen evaluointisysteemi. Tässä diplomityössä käytetty liityntäsolmu ei omaa kytkentätoimintoa vielä, joten sitä voidaan käyttää ainoastaan keskittimenä. Koska ATM-verkkojen tulevaisuuden arkkitehtuuri ei ole kovin selvä, ATM-kytkinpiirisarjan käyttö ainakin mahdollistaa tämän toiminnon suhteellisen helpon lisäämisen, jos tarve vaatii. Alkuosa tästä diplomityöstä käsittelee ATM:n peruskäsitteitä, ATM-verkkoja sekä kytkemistä ATM-verkoissa. Sen jälkeen on vertailututkimus kolmen eri kytkinpiirisarjan soveltumisesta käytettäväksi liityntäsolmussa. Loppuosa käsittelee evaluointisysteemin suunnittelua ja rakentamista IDT SWITCHStAR[TM ] kytkinpiirisarjalle. Aivan lopussa on vielä kommentteja ja johtopäätöksiä tämän diplomityön kulusta ja tuloksista sekä ehdotelma siitä kuinka IDT:n kytkinpiirisarjaa voitaisiin käyttää osana liityntäsolmua