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The Global ETD Search service is a free service for researchers
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Showing 1 to 2 of 2 (0.034 seconds)Spelling suggestions: "subject:"packet switched"" "subject:"jacket switched""
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Design and Evaluation of the Combined Input and Crossbar Queued (CICQ) SwitchYoshigoe, Kenji 09 August 2004 (has links)
Packet switches are used in the Internet to forward information between a sender and receiver and are the critical bottleneck in the Internet. Without faster packet switch designs, the Internet cannot continue to scale-up to higher data rates. Packet switches must be able to achieve high throughput and low delay. In addition, they must be stable for all traffic loads, must efficiently support variable length packets, and must be scalable to higher link data rates and greater numbers of ports. This dissertation investigates a new combined input and crossbar queued (CICQ) switch architecture.
Some unbalanced traffic loads result in instability for input queued (IQ) and CICQ switches. This instability region was modeled, and the cause of the instability was found to be a lack of work conservation at one port. A new burst stabilization protocol was investigated that was shown to stabilize both IQ and CICQ switches. As an added benefit, this new protocol did not require a costly internal switch speed-up. Switching variable length packets in IQ switches requires the segmentation of packets into cells. The process also requires an internal switch speed-up which can be costly. A new method of cell-merging in IQ switches reduced this speed-up. To improve fairness for CICQ switches, a block and transfer method was proposed and evaluated.
Implementation feasibility of the CICQ switch was also investigated via a field programmable gate array (FPGA) implementation of key components. Two new designs for round robin arbiters were developed and evaluated. The first of these, a proposed priority-encoder-based round robin arbiter that uses feedback masking, has a lower delay than any known design for an FPGA implementation. The second, an overlapped round robin arbiter design that fully overlaps round robin polling and scheduling, was proposed and shown to be scalable, work conserving, and fair.
To allow for multi-cabinet implementation and minimization of the size of the cross point buffers, a distributed input port queue scheduler was investigated. This new scheduler minimizes the amount of buffering needed within the crossbar.
The two primary contributions of this dissertation are 1) a complete understanding of the performance characteristics of the CICQ switch, and 2) new methods for improving the performance, stability,and scalability of the CICQ switch. This work has shown that the CICQ switch can be the switch architecture of the future.
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Changing from the silo model to the horizontal layers model in public policy regulations: the implications and potential for the telecommunications industrySpencer Logan, Lemuella C. 12 1900 (has links)
The end of the Twentieth Century and the start of the Twenty First Century has been a tumultuous time for the Telecommunications Industry. Even as it moves forward to embrace the new technologies the Industry finds itself embroiled in issues of governance. The Industry finds itself in a dilemma since innovations increase at a rate faster than the laws can be changed and these render its existing laws and policies to be in some cases obsolete and inappropriate for the reality of the present. In the past, the United States of America has relied on vertically integrated top down laws and methods of regulating all the different parts in its Telecommunications Industry. These laws are contained in the different numbered Titles of this Countrys Legal Codes. Since the inception of these laws, emphasis was placed in creating and documenting policies structured by industry, sector and type of content. This form of regulation is usually referred to as the Silo Method. However, in recent years, especially in the regulation of the Telephony industry, the method of law and rule formulation moved from content regulation to one in which the technologies are getting regulated in what has been described as a Layers Method. This paper first considered whether the Silo Method of regulation is in actuality the same as using the Horizontal Layers method and showed that this is the case. Then it determined that Enhanced Services are the same as Basic Services and that Telecommunications Services are the same as Information services and showed that given that the pair sets as noted were the same, it went on to conclude that all these services were essentially the same. While studying to some detail the technologies of VoIP, the paper also showed that VoIP although an Internet technology is similar to traditional telephony, and is both a Telecommunications Service and Information Service based on the definition as given in the law as well as the technologies that are used and that as a result of this, the current regulatory environment for this service with regards to telephony is inconsistent. It concluded that Telecommunications policies though now adequate may need to be modified.
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