Low Cost Quality of Service Multicast Routing in High Speed Networks

Many of the services envisaged for high speed networks, such as B-ISDN/ATM, will support real-time applications with large numbers of users. Examples of these types of application range from those used by closed groups, such as private video meetings or conferences, where all participants must be known to the sender, to applications used by open groups, such as video lectures, where partcipants need not be known by the sender. These types of application will require high volumes of network resources in addition to the real-time delay constraints on data delivery. For these reasons, several multicast routing heuristics have been proposed to support both interactive and distribution multimedia services, in high speed networks. The objective of such heuristics is to minimise the multicast tree cost while maintaining a real-time bound on delay. Previous evaluation work has compared the relative average performance of some of these heuristics and concludes that they are generally efficient, although some perform better for small multicast groups and others perform better for larger groups. Firstly, we present a detailed analysis and evaluation of some of these heuristics which illustrates that in some situations their average performance is reversed; a heuristic that in general produces efficient solutions for small multicasts may sometimes produce a more efficient solution for a particular large multicast, in a specific network. Also, in a limited number of cases using Dijkstra's algorithm produces the best result. We conclude that the efficiency of a heuristic solution depends on the topology of both the network and the multicast, and that it is difficult to predict. Because of this unpredictability we propose the integration of two heuristics with Dijkstra's shortest path tree algorithm to produce a hybrid that consistently generates efficient multicast solutions for all possible multicast groups in any network. These heuristics are based on Dijkstra's algorithm which maintains acceptable time complexity for the hybrid, and they rarely produce inefficient solutions for the same network/multicast. The resulting performance attained is generally good and in the rare worst cases is that of the shortest path tree. The performance of our hybrid is supported by our evaluation results. Secondly, we examine the stability of multicast trees where multicast group membership is dynamic. We conclude that, in general, the more efficient the solution of a heuristic is, the less stable the multicast tree will be as multicast group membership changes. For this reason, while the hybrid solution we propose might be suitable for use with closed user group multicasts, which are likely to be stable, we need a different approach for open user group multicasting, where group membership may be highly volatile. We propose an extension to an existing heuristic that ensures multicast tree stability where multicast group membership is dynamic. Although this extension decreases the efficiency of the heuristics solutions, its performance is significantly better than that of the worst case, a shortest path tree. Finally, we consider how we might apply the hybrid and the extended heuristic in current and future multicast routing protocols for the Internet and for ATM Networks.

Segment Routing: a Comprehensive Survey of Research Activities, Standardization Efforts and Implementation Results

Fixed and mobile telecom operators, enterprise network operators and cloud providers strive to face the challenging demands coming from the evolution of IP networks (e.g. huge bandwidth requirements, integration of billions of devices and millions of services in the cloud). Proposed in the early 2010s, Segment Routing (SR) architecture helps face these challenging demands, and it is currently being adopted and deployed. SR architecture is based on the concept of source routing and has interesting scalability properties, as it dramatically reduces the amount of state information to be configured in the core nodes to support complex services. SR architecture was first implemented with the MPLS dataplane and then, quite recently, with the IPv6 dataplane (SRv6). IPv6 SR architecture (SRv6) has been extended from the simple steering of packets across nodes to a general network programming approach, making it very suitable for use cases such as Service Function Chaining and Network Function Virtualization. In this paper we present a tutorial and a comprehensive survey on SR technology, analyzing standardization efforts, patents, research activities and implementation results. We start with an introduction on the motivations for Segment Routing and an overview of its evolution and standardization. Then, we provide a tutorial on Segment Routing technology, with a focus on the novel SRv6 solution. We discuss the standardization efforts and the patents providing details on the most important documents and mentioning other ongoing activities. We then thoroughly analyze research activities according to a taxonomy. We have identified 8 main categories during our analysis of the current state of play: Monitoring, Traffic Engineering, Failure Recovery, Centrally Controlled Architectures, Path Encoding, Network Programming, Performance Evaluation and Miscellaneous...Comment: SUBMITTED TO IEEE COMMUNICATIONS SURVEYS & TUTORIAL

Performance evaluation of multicast routing on IPv4 and IPv6 networks

Even though the transition from IPv4 to IPv6 has not been realized at the pace that it was anticipated, eventually with the depletion of IPv4 address space and the ever-growing demands of the Internet, the transition is inevitable. In the rapidly evolving world of technology, multimedia applications and voice/video conferencing are fast finding their ways into the Internet and corporate networks. Multicast routing protocols run over unicast routing protocols to provide efficient routing of such applications. This thesis was aimed at understanding how the transition from IPv4 to IPv6 would impact multicast routing. The multicast routing protocol Protocol Independent Multicast-Sparse Mode (PIM-SM) was used over both IPv4 and IPv6 networks and a mixed IPv4-IPv6 network. Parameters such as protocol overheads, throughput and jitter were evaluated in a lab environment using jperf

Adjacency Persistency in OSPF MANET

Link-state routing remains as one of the most challenging issues in ad hoc networking, due to the special conditions and requirements that hold in such networks, which cannot be handled by classical routing protocols. In the last decade, several efforts have been deployed either to design new routing solutions adapted to ad hoc conditions, either to extend existing solutions for wired networks to the domain of wireless mobile scenarios. This paper elaborates on the latter alternative, focusing on the standard OSPF MANET extension RFC 5449. It analyzes the impact and interest of the persistency principle to the main OSPF MANET operations, in particular the adjacency synchronization and the other operations that relate to it (flooding and route construction). The presented results show that such persistent approach is appropriate for managing adjacencies in the context of RFC 5449, and significant improvements might be achieved by extending the persistent principle into the topology selection mechanism.Le routage d'état-lieu (link-state) reste comme l'une des questions les plus difficiles dans un réseau ad hoc, en raison des conditions particulières et des exigences qui tiennent à de tels réseaux, qui ne peuvent êre traitées par les protocoles de routage classiques. Dans la dernière décennie, plusieurs efforts ont été déployés, soit pour concevoir de nouvelles solutions de routage adaptées aux conditions ad hoc, soit pour étendre les solutions existantes pour les réseaux filaires au domaine des scénarios wireless mobiles. Ce document détaille la dernière alternative, en se concentrant sur l'extension standard RFC 5449 OSPF MANET. Il analyse l'impact et l'intérêt du principe de "persistance" sur des opérations principales au context OSPF MANET, en particulier la synchronisation des adjacences et les autres opérations qui s'y rapportent (flooding et construction de routes). Les résultats présentés montrent que cette approche persistante est appropriée pour la gestion des adjacences dans le cadre du RFC 5449, et des améliorations significatives peuvent être obtenues en étendant le principe de "persistance" au mécanisme de sélection topologique

Multi-Hop Wireless Networking with OSPF: MPR-based Routing Extensions for MANETs

Incorporating multi-hop wireless networks in the IP infrastructure is an effort to which a growing community participates. One instance of such activity is the extension of the routing protocol OSPF, for operation on MANETs. Such extension allows OSPF, the most widely deployed interior gateway routing protocol on the Internet, to work on heterogeneous networks encompassing both wired and wireless routers. The latter may self-organize as multi-hop wireless subnetworks, and may be mobile. Three solutions have been proposed for this extension, among which two based on techniques derived from multi-point relaying (MPR) techniques and OLSR. This paper analyzes these two approaches and identifies some fundamental discussion items that pertain to adapting OSPF mechanisms to multi-hop wireless networking, before concluding with a proposal for a unique, merged solution based on this analysis

Multicast Delivery of IPTV Over the Internet

Television represents one of the greatadvancements in information delivery. Traditionally, televisionservice has been delivered using dedicated communicationmethods such as terrestrial and satellite based wirelesstransmissions and fixed cable based transmissions. Some of thesedelivery mechanisms have advanced and now provide servicesincluding voice and Internet access. Another communicationmethod, traditional telephone service, has greatly improvedand expanded to deliver services such as television and Internetaccess.This convergence of service provides cost savings, allowingproviders to utilize existing communication networks to deliveradditional services to its customers, often at minimal or zeroinfrastructure cost. One disadvantage of this method is customerreach is still limited to those with access to dedicated serviceprovider networks. The ability to disengage television servicefrom these dedicated networks and move it to a more ubiquitousnetwork would greatly improve the customer reach of theproviders.The most obvious network choice for a delivery mediumis the Internet. Given that television delivery mechanisms havealready started the progression towards IPTV, the service isa natural fit. One issue hindering this transition is bandwidthavailability. In private delivery networks, the issue of bandwidthavailability for IPTV is often combated through the use of IPMulticasting. Considering the Internet is already believed to bebandwidth constrained, the use of multicasting could be deemeda requirement. The following paper will explore current issueswith deploying IPTV over the Internet, the use of multicast tocombat some of these problems, and the inherent challenges ofpushing multicast based IPTV services over the Internet

Rete GARR-B: Piano di routing IP multicast

The IP multicast was introduced in the GARR network (Italian Network for University and Scientific Community) in 1993 with the connection to Mbone (worldwide virtual multicast network). Since then the Italian Mbone developed constantly allowing the test of protocols and applications. Nevertheless the original Mbone structure is not suitable for an efficient utilization of multicast potentialities and advantages, preventing from exploiting all the services on a large scale; moreover it doesn\u27t allow an interconnection with those ISP which are enabling multicast in their networks but with different technical solutions. This document, after a description of the limits of the present Mbone on GARR, proposes the steps for an updating plane: - IP multicast implementation on the production routers of the backbone, using the PIM-SM protocol; - choice and configuration of the Rendez-Vous Points; - definition of IP multicast boundary routers; - bandwidth limitation; - inter-domain routing (MSDP and MBGP); - international multicast connections. The document deals with some of IP multicast management tools, as well.L\u27introduzione del multicast IP sulla rete GARR (Rete per l\u27Universit? e la Ricerca Scientifica Italiana) risale al 1993 con la prima connessione a Mbone (rete virtuale multicast mondiale). Da allora c\u27e\u27 stato un costante sviluppo sulla Mbone italiana che ha reso possibile la sperimentazione di protocolli e applicativi. Tuttavia la struttura originaria di Mbone non consente un utilizzo efficace delle potenzialita\u27 e dei vantaggi del multicast, precludendo la possibilita\u27 di sfruttarne appieno i servizi su larga scala; cosi\u27 come non consente l\u27interconnessione con quegli ISP che stanno gia\u27 abilitando le loro reti al multicast con soluzioni tecniche diverse. Questo documento, dopo una descrizione dei limiti dell\u27attuale Mbone sul GARR, ne propone le fasi necessarie per un piano di aggiornamento: - implementazione di IP multicast sulla dorsale sui router di produzione con protocollo PIM-SM; - scelta e configurazione dei Rendez-Vous Point; - definizione delle frontiere amministrative (boundary router); - limitazioni di banda; - inter-domain routing (MSDP e MBGP); - connessioni multicast internazionali. Il documento contiene anche un accenno ad alcuni degli strumenti utilizzabili per la gestione dell?IP multicast