《activenetworks,(andreliablemulticast)：主动网络，（和可靠多播）》由会员分享，可在线阅读，更多相关《activenetworks,(andreliablemulticast)：主动网络，（和可靠多播）（54页珍藏版）》请在金锄头文库上搜索。
1、Communication networks, active networking and reliable multicast,C. PHAM Mardi 12 juin, 2001,Outline,Introduction Nowadays network technologies Active networking Application: Active Reliable Multicast Conclusions,Outline,Introduction Nowadays network technologies Active networking Application: Activ
2、e Reliable Multicast Conclusions,The need for communication,The way people are communicating,Internet milestone,User perspective of the Internet,from UREC, http:/www.urec.fr,What it is in reality,from UREC, http:/www.urec.fr,Outline,Introduction Nowadays network technologies Active networking Applic
3、ation: Active Reliable Multicast Conclusions,Links: the basic element for networking,Backbone links optical fibers 10 to 160 GBits/s with DWDM techniques End-user access V.90 56KBits/s modem on twisted pair 512Kbits/s to 2MBits/s with xDSL modem 1Mbits/s to 10Mbits/s Cable-modem 64Kbits/s to 1930KBi
4、ts/s ISDN access 9.6KBits/s (GSM) to 2MBits/s (UMTS),Routers: key elements of internetworking,Routers run routing protocols and build routing table, receive data packets and perform relaying, may have to consider Quality of Service constraints for scheduling packets, are highly optimized for packet
5、forwarding functions.,General architecture of an IP router,receives input packets, sends packets to output buffers, transmits packets (with QoS?).,Desires put on the general Internet,High-bandwidth for bandwidth-consuming applications Ubiquity of the network access (wireless, RTC, xDSL, mobile) for
6、remaining connected everywhere Quality of Service for high-quality multimedia reception Dynamicity, adaptability to take into account recent technologies,Challenges for the Internet,high-speed www video-conferencing video-on-demand interactive TV programs tele-medecine high-performance computing, gr
7、ids virtual reality, immersion systems distributed interactive simulations remote archival systems,The reality(1),High-bandwidth accesses are not available for everybody high-bandwidth is achievable in the core network with optical fibers and DWDM techniques but, most end-users have an access rangin
8、g from 56Kbits/s to 2Mbits/s and, it will be the case for many years!,The reality(2),An ubiquitous network access generally implies heterogeneity and asymmetric performances, how to take into account this heterogeneity? The heterogeneity of bandwidth makes QoS a difficult quest on an end-to-end basi
9、s, seems that QoS is the networking forever Graal,The reality(3),New technologies require years to be deployed need for standardization IPv6, MPLS new services and protocols are costly to deploy many proprietary implementations, no interoperability of services and new technologies DiffServ, TagSwitc
10、hing, LabelSwitching,Towards a better Internet,Interoperability of systems Rapid deployment of new services, accelerating infrastructure innovation Take into account the heterogeneity of needs and network accesses Customization of services, application-oriented processing features,Towards the concep
11、t of,Introduction Nowadays network technologies Active networking Application: Active Reliable Multicast Conclusions,What is active networks?,Programmable nodes/routers Customized computations on packets Standardized execution environment and programming interface No killer applications, only a diff
12、erent way to offer high-value services, in an elegant manner However, adds extra processing cost,Motivations behind Active Networking,From the user perspective applications can specify, implement, and deploy (on-the-fly) customized services and protocols From the operator perspective reduce the late
13、ncy/cost for new services deployment/management From the network perspective globally better performances by reducing the amount of traffic,Active networks implementations,Discrete approach (operators approach) Adds dynamic deployment features in nodes/routers New services can be downloaded into rou
14、ters kernel Integrated approach Adds executable code to data packets Capsule = data + code Granularity set to the packets,The discrete approach,Separates the injection of programs from the processing of packets,The integrated approach,User packets carry code to be applied on the data part of the pac
15、ket High flexibility to define new services,data,An active router,some layer for executing code. Lets call it Active Layer,Interoperability with legacy routers,IP,IP,IP,IP,IP,IP,TCP/UDP,TCP/UDP,TCP/UDP,TCP/UDP,AL,AL,AL,AL,traditional IP routing,APPLI,APPLI,Some open problems,Security and integrity h
16、ow to be sure that user code are safe? Performances how to add active computation without weeping out performances? Standardization of programming interface How to bill the CPU time?,Some active network applications,Customization of services Web-caching, on-the-fly compression/encryption Filtering Auction, Distributed Interactive Simulations, HLA Firewall Congestion control QoS Network management Reliable multicast Middleware collective operation,Where to put
