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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

On the Routing Lookup Algorithm for IPv6

Chang, Wei-Che 06 July 2000 (has links)
As the Internet grows, there are several problems needed be solve. First, the IP addresses will be exhausted. The 128 bits IPv6 addresses will replace the 32 bits IPv4 addresses to solve the problem. Secondly, routers become the bottlenecks of networks. There are many routing lookup algorithms to improve routers' performance. In July 1998, the detail address formats of IPv6 are defined by the IETF in RFC 2373, 2374 and 2375. These definitions make the discussion of routing lookup algorithms from IPv4 to IPv6 become possible. This paper focuses on the scalability of performing those IPv4 routing lookup algorithms for IPv6. The paper also proposals a new IPv6 lookup algorithm based on the characteristics of the IPv6 address formats. Chapter 1 is introduction. Chapter 2 introduces the current IPv6 addressing types and reviews previous work on IPv4. Chapter 3 presents our modified IPv6 routing lookup algorithm. Chapter 4 describes the generation of the test patterns for IPv6 lookups and presents the simulation results. Chapter 5 concludes this paper.
2

IP routing lookup: hardware and software approach

Chakaravarthy, Ravikumar V. 29 August 2005 (has links)
The work presented in this thesis is motivated by the dual goal of developing a scalable and efficient approach for IP lookup using both hardware and software approach. The work involved designing algorithms and techniques to increase the capacity and flexibility of the Internet. The Internet is comprised of routers that forward the Internet packets to the destination address and the physical links that transfer data from one router to another. The optical technologies have improved significantly over the years and hence the data link capacities have increased. However, the packet forwarding rates at the router have failed to keep up with the link capacities. Every router performs a packet-forwarding decision on the incoming packet to determine the packet??s next-hop router. This is achieved by looking up the destination address of the incoming packet in the forwarding table. Besides increased inter-packet arrival rates, the increasing routing table sizes and complexity of forwarding algorithms have made routers a bottleneck in the packet transmission across the Internet. A number of solutions have been proposed that have addressed this problem. The solutions have been categorized into hardware and software solutions. Various lookup algorithms have been proposed to tackle this problem using software approaches. These approaches have proved more scalable and practicable. However, they don??t seem to be able to catch up with the link rates. The first part of my thesis discusses one such software solution for routing lookup. The hardware approaches today have been able to match up with the link speeds. However, these solutions are unable to keep up with the increasing number of routing table entries and the power consumed. The second part of my thesis describes a hardware-based solution that provides a bound on the power consumption and reduces the number of entries required to be stored in the routing table.
3

Geometric Filter: A Space and Time Efficient Lookup Table with Bounded Error

Zhao, Yang 11 1900 (has links)
Lookup tables are frequently used in many applications to store and retrieve keyvalue pairs. Designing efficient lookup tables can be challenging with constraints placed on storage, query response time and/or result accuracy. This thesis proposes Geometric filter, a lookup table with a space requirement close to the theoretical lower bound, efficient construction, fast querying speed, and guaranteed accuracy. Geometric filter consists of a sequence of hash tables, the sizes of which form a descending geometric series. Compared with its predecessor, Bloomier filter, its encoding runs two times faster, uses less memory, and it allows updates after encoding. We analyze the efficiency of the proposed lookup table in terms of its storage requirement and error bound, and run experiments on Web 1TB 5-gram dataset to evaluate its effectiveness.
4

Towards more power efficient IP lookup engines

Ahmad, Seraj 25 April 2007 (has links)
The IP lookup in internet routers requires implementation of the longest prefix match algorithm. The software or hardware implementations of routing trie based approaches require several memory accesses in order to perform a single memory lookup, which limits the throughput considerably. On the other hand, IP lookup throughput requirements have been continuously increasing. This has led to ternary content addressable memory(TCAM) based IP lookup engines which can perform a single lookup every cycle. TCAM lookup engines are very power hungry due to the large number of entries which need to be simultaneously searched. This has led to two disparate streams of research into power reduction techniques. The first research stream focuses on the routing table compaction using logic minimization techniques. The second stream focuses on routing table partitioning. This work proposes to bridge the gap by employing strategies to combine these two leading state of the art schemes. The existing partitioning algorithms are generally employed on a binary routing trie precluding their application to a compacted routing table. The proposed scheme employs a ternary routing trie to facilitate the representation of the minimized routing table in combination with the ternary trie partitioning algorithm. The combined scheme offers up to 50% reduction in silicon area while maintaining the power economy of the partitioning scheme.
5

Geometric Filter: A Space and Time Efficient Lookup Table with Bounded Error

Zhao, Yang Unknown Date
No description available.
6

An IPv6 Routing Table Lookup Algorithm in Software and ASIC by Designing a High-Level Synthesis System

Islam, MD I. 21 July 2022 (has links)
No description available.
7

Memory Reduction of Table-based Function Evaluation Methods

Huang, Wen-Liang 10 August 2010 (has links)
In many digital signal processing applications, we often need some special function units that can compute complicated arithmetic functions such as reciprocal, logarithm, power of 2, trigonometric functions, etc. The most popular designs are based on look-up tables with polynomial approximation. However, the table size will increase significantly in accordance with precision. In this thesis, we propose a method called remapping to reduce the table size by using non-uniform segmentation. When we obtain the coefficients for all segments, we do not store them in order. By sorting the coefficients in the ROM ,we design a efficient hardware mapping. The method can reduce the ROM size with lower extra cost spent in address mapping for non-uniform segmentation.
8

Power and Memory Efficient Hashing Schemes for Some Network Applications

Yu, Heeyeol 2009 May 1900 (has links)
Hash tables (HTs) are used to implement various lookup schemes and they need to be efficient in terms of speed, space utilization, and power consumptions. For IP lookup, the hashing schemes are attractive due to their deterministic O(1) lookup performance and low power consumptions, in contrast to the TCAM and Trie based approaches. As the size of IP lookup table grows exponentially, scalable lookup performance is highly desirable. For next generation high-speed routers, this is a vital requirement when IP lookup remains in the critical data path and demands a predictable throughput. However, recently proposed hash schemes, like a Bloomier filter HT and a Fast HT (FHT) suffer from a number of flaws, including setup failures, update overheads, duplicate keys, and pointer overheads. In this dissertation, four novel hashing schemes and their architectures are proposed to address the above concerns by using pipelined Bloom filters and a Fingerprint filter which are designed for a memory-efficient approximate match. For IP lookups, two new hash schemes such as a Hierarchically Indexed Hash Table (HIHT) and Fingerprint-based Hash Table (FPHT) are introduced to achieve a a perfect match is assured without pointer overhead. Further, two hash mechanisms are also proposed to provide memory and power efficient lookup for packet processing applications. Among four proposed schemes, the HIHT and the FPHT schemes are evaluated for their performance and compared with TCAM and Trie based IP lookup schemes. Various sizes of IP lookup tables are considered to demonstrate scalability in terms of speed, memory use, and power consumptions. While an FPHT uses less memory than an HIHT, an FPHT-based IP lookup scheme reduces power consumption by a factor of 51 and requires 1.8 times memory compared to TCAM-based and trie-based IP lookup schemes, respectively. In dissertation, a multi-tiered packet classifier has been proposed that saves at most 3.2 times power compared to the existing parallel packet classifier. Intrinsic hashing schemes lack of high throughput, unlike partitioned Ternary Content Addressable Memory (TCAM)-based scheme that are capable of parallel lookups despite large power consumption. A hybrid CAM (HCAM) architecture has been introduced. Simulation results indicate HCAM to achieve the same throughput as contemporary schemes while it uses 2.8 times less memory and 3.6 times less power compared to the contemporary schemes.
9

Implementation and Acceleration of a Particle Filter for Indoor Localization in FPGA Hardware / Implementation och acceleration av ett partikelfilter för inomhuslokalisering i FPGA-hårdvara

Moberg, David January 2015 (has links)
For this thesis the algorithm of a Particle Filter has been partly implemented on a Zynq All-programmable SoC allowing for speed ups of up to 12 times in parts of the code. The implementation is used to track a robot in an environment known by a 2D map. Since some parts have not been implemented in hardware lots of communication is done between the hardware and software parts of the code which creates a performance bottleneck.
10

Geo-process lookup management

Hägglund, Andreas January 2017 (has links)
This thesis presents a method to deploy and lookup applications and devices based on a geographical location. The proposed solution is a combination of two existing technologies, where the first one is a geocode system to encode latitude and longitude coordinates, and the second one is a Distributed Hash Table (DHT) where values are stored and accessed with a $<$key,value$>$ pair. The purpose of this work is to be able to search a specific location for the closest device that solves the user needs, such as finding an Internet of Things (IoT) device. The thesis covers a method for searching by iterating key-value pairs in the DHT and expanding the area to find the devices further away. The search is performed using two main algorithm implementations LayerExpand and SpiralBoxExpand, to scan the area around where the user started the search. LayerExpand and SpiralBoxExpand are tested and evaluated in comparison to each other. The comparison results are presented in the form of plots where both of the functions are shown together. The function analysis results show how the size of the DHT, the number of users, and size of the search area affects the performance of the searches.

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