عنوان مقاله
سوئیچینگ غیر سنکرون( ناهمزمان) SAN تحت ترافیک چند بخشی
فهرست مطالب
چکیده
مقدمه
معماری سیستم
نتایج عملکرد
نتیجه گیری
بخشی از مقاله
معماری سیستم
سوئیچ از فابریک سوئیچینگ بافری، و تعداد معلومی کارت خط متشکل از بافرهای ورودی و خروجی تشکیل می شود که درشکل 1 نشان داده شده است. هر کارت خط از یک پورت ورودی و یک پورت خروجی تشکیل می شود. کارت های خط بسته ها را دریافت و آنها را در بافرهای ورودی ذخیره می کنند. فابریک سوئیچینگ بسته های چند بخشی را از بافر ورودی کارت خط به کارت های خطی منتقل می کند که میزبان پورت های خروجی مقصد بوده و برای این کاراز قابلیت چند بخشی ذاتی استفاده می کند. لینک هایI/O فابریک سوئیچینگ نه تصویب شده و نه یک تنگنا را تشکیل می دهند. سیگنالهای کنترل فشار معکوس، دسترسی بافر به منظور اجتناب از تلفات داده ها را تنظیم می کنند.
کلمات کلیدی:
Asynchronous SAN Switching under Multicast Traffic Andrea Bianco *, Luca Giraudo *, Alessandra Scicchitano t * Dip. di Elettronica, Politecnico di Torino, Italy, Email: {name.surname}@polito.it t IBM Research, Zurich Research Laboratory, 8803 Riischlikon, Switzerland, Email: {als}@zurich.ibm.com Abstract-Multicast traffic in Storage Area Networks (SANs) enables applications such as disaster recovery, remote data replication and distributed multimedia systems, in which a server access concurrently multiple storage devices or, conversely, multiple servers access data on a single device. Thus, an asynchronous loss-less switching architecture devised for SANs is described, and its performance under multicast traffic is studied. Simulations are used to analyze switch performance under various traffic patterns and schedulers. Although most of the simulations refer to a specific switch architecture, performance results highlight interesting general trends in flow controlled asynchronous architectures. These architectures could be used effectively also in a more traditional data switching and routing scenario. In this case, multicast support becomes essential to support multimedia QoS aware applications and protocols heavily relying on the broadcast property of LANs. I. INTRODUCTION High-speed packet-switched networks, named Storage Area Networks (SANs), are replacing direct connections between servers and storage resources. Indeed, SANs provide more flexibility, overcome the performance, scalability, reliability and management problems of the traditional Directly Attached Storage (DAS) paradigm, and enable consolidation and virtualization of storage resources. To ensure reliability, lossfree operation is envisioned. Both buffer-to-buffer and end-toend flow-control mechanisms are proposed in Fibre Channel standards [1] to control the rate at which frames are received from upstream nodes to avoid frame losses and reordering. Multicast support in SANs enables critical applications such as disaster recovery, in which a server stores multiple copies of the same data at geographically distant sites (similar to RAID-l mode), and distributed multimedia systems [2], in which multiple servers access data (typically video streams) stored in a central repository and deliver it to their local pool of users [3]. In this paper we present a switch architecture designed for SANs, and study its performance under multicast traffic. Multicast packets are characterized by their fanout set, Le., by the set of output ports (destinations) to which they are directed. The packet fanout is defined as the number of different destinations of a multicast packet, Le., the cardinality of the fanout set. All the packets arriving to the same input and with the same fanout set identify a multicast flow. Unicast traffic is not given special attention, Le., it is considered as a particular case of multicast traffic with fanout 1.
