This In the past decade there has been an increasing need for designs to address the time and cost efficiency issues from various computer network applications such as general IP address lookup and specific network in...This In the past decade there has been an increasing need for designs to address the time and cost efficiency issues from various computer network applications such as general IP address lookup and specific network intrusion detection. Hashing techniques have been widely adopted for this purpose, among which XOR-operation-based hashing is one of most popular techniques due to its relatively small hash process delay. In most current commonly used XOR-hashing algorithms, each of the hash key bits is usually explicitly XORed only at most once in the hash process, which may limit the amount of potential randomness that can be introduced by the hashing process. In [1] a series of bit duplication techniques are proposed by systematically duplicating one row of key bits. This paper further looks into various ways in duplicating and reusing key bits to maximize randomness needed in the hashing process so as to enhance the overall performance further. Our simulation results show that, even with a slight increase in hardware requirement, a very significant reduction in the amount of hash collision can be obtained by the proposed technique.展开更多
Routing technology has been forced to evolve towards higher capacity and per port packet processing speed. The ability to achieve high forwarding speed is due to either software or hardware technology. TCAM (Ternary C...Routing technology has been forced to evolve towards higher capacity and per port packet processing speed. The ability to achieve high forwarding speed is due to either software or hardware technology. TCAM (Ternary Content Addressable Memory) provides a performance advantage over other software or hardware search algorithms, often resulting in an order of magnitude reduction of search time. But slow updates may affect the performance of TCAM based routing lookup. So the key is to design a table management algorithm, which supports high speed updates in TCAMs. This paper presented three table management algorithms, and then compared their performance. Finally, the optimal one after comparing was given.展开更多
可变长地址是未来网络领域的重要研究内容之一。针对传统路由查找算法在面向可变长地址时查找效率低的问题,提出一种基于平衡二叉树AVL(Adelson-Velskii and Landis)树和Bloom过滤器的适用于可变长地址的高效路由查找算法,简称为AVL-Bl...可变长地址是未来网络领域的重要研究内容之一。针对传统路由查找算法在面向可变长地址时查找效率低的问题,提出一种基于平衡二叉树AVL(Adelson-Velskii and Landis)树和Bloom过滤器的适用于可变长地址的高效路由查找算法,简称为AVL-Bloom算法。首先,针对可变长地址灵活可变且无界的特点,利用多个片外哈希表分别存储前缀比特位数相同的路由条目及其下一跳信息,同时应用片上Bloom过滤器加速搜索可能匹配的路由前缀;其次,为了解决基于哈希技术的路由查找算法在查找最长前缀路由时需多次哈希对比的问题,引入AVL树技术,即通过AVL树组织每组路由前缀集合的Bloom过滤器及其哈希表,优化路由前缀长度的查询顺序,并减少哈希计算次数进而降低查询时间;最后,在3种不同的可变长地址数据集上将所提算法与METrie(Multi-Entrance-Trie)和COBF(Controlled prefix and One-hashing Bloom Filter)这两种传统路由查找算法进行对比实验。实验结果表明,AVL-Bloom算法的查询时间明显少于METrie和COBF算法,分别减少了将近83%和64%;同时,AVL-Bloom算法在路由表项数变化较大的情况下也能维持稳定的查找性能,适用于可变长地址的路由查找转发。展开更多
针对IP路由器的FIB(Forwarding Information Base)极限问题和分布式IP地址查找中的通信延迟问题,提出了SD-Torus(Semi-Diagonal Torus)直连网络。按照"临近存储"的原则,将路由表划分后存储在每个节点及其邻居节点上,以减少分...针对IP路由器的FIB(Forwarding Information Base)极限问题和分布式IP地址查找中的通信延迟问题,提出了SD-Torus(Semi-Diagonal Torus)直连网络。按照"临近存储"的原则,将路由表划分后存储在每个节点及其邻居节点上,以减少分布式IP地址查找中的通信延迟,提高整体的查找性能。在分析SD-Torus网络拓扑性质的基础上,提出了一种负载均衡的路由算法。基于SystemC的仿真结果表明,使用该结构可以大大降低分布式IP地址查找的通信延迟,提高系统的扩展性。该研究结果可以应用于高性能的分布式IP地址查找。展开更多
The feature of Ternary Content Addressable Memories(TCAMs) makes them particularly attractive for IP address lookup and packet classification applications in a router system. However,the limitations of TCAMs impede th...The feature of Ternary Content Addressable Memories(TCAMs) makes them particularly attractive for IP address lookup and packet classification applications in a router system. However,the limitations of TCAMs impede their utilization. In this paper,the solutions for decreasing the power consumption and avoiding entry expansion in range matching are addressed. Experimental results demonstrate that the proposed techniques can make some big improvements on the performance of TCAMs in IP address lookup and packet classification.展开更多
文摘This In the past decade there has been an increasing need for designs to address the time and cost efficiency issues from various computer network applications such as general IP address lookup and specific network intrusion detection. Hashing techniques have been widely adopted for this purpose, among which XOR-operation-based hashing is one of most popular techniques due to its relatively small hash process delay. In most current commonly used XOR-hashing algorithms, each of the hash key bits is usually explicitly XORed only at most once in the hash process, which may limit the amount of potential randomness that can be introduced by the hashing process. In [1] a series of bit duplication techniques are proposed by systematically duplicating one row of key bits. This paper further looks into various ways in duplicating and reusing key bits to maximize randomness needed in the hashing process so as to enhance the overall performance further. Our simulation results show that, even with a slight increase in hardware requirement, a very significant reduction in the amount of hash collision can be obtained by the proposed technique.
文摘Routing technology has been forced to evolve towards higher capacity and per port packet processing speed. The ability to achieve high forwarding speed is due to either software or hardware technology. TCAM (Ternary Content Addressable Memory) provides a performance advantage over other software or hardware search algorithms, often resulting in an order of magnitude reduction of search time. But slow updates may affect the performance of TCAM based routing lookup. So the key is to design a table management algorithm, which supports high speed updates in TCAMs. This paper presented three table management algorithms, and then compared their performance. Finally, the optimal one after comparing was given.
文摘可变长地址是未来网络领域的重要研究内容之一。针对传统路由查找算法在面向可变长地址时查找效率低的问题,提出一种基于平衡二叉树AVL(Adelson-Velskii and Landis)树和Bloom过滤器的适用于可变长地址的高效路由查找算法,简称为AVL-Bloom算法。首先,针对可变长地址灵活可变且无界的特点,利用多个片外哈希表分别存储前缀比特位数相同的路由条目及其下一跳信息,同时应用片上Bloom过滤器加速搜索可能匹配的路由前缀;其次,为了解决基于哈希技术的路由查找算法在查找最长前缀路由时需多次哈希对比的问题,引入AVL树技术,即通过AVL树组织每组路由前缀集合的Bloom过滤器及其哈希表,优化路由前缀长度的查询顺序,并减少哈希计算次数进而降低查询时间;最后,在3种不同的可变长地址数据集上将所提算法与METrie(Multi-Entrance-Trie)和COBF(Controlled prefix and One-hashing Bloom Filter)这两种传统路由查找算法进行对比实验。实验结果表明,AVL-Bloom算法的查询时间明显少于METrie和COBF算法,分别减少了将近83%和64%;同时,AVL-Bloom算法在路由表项数变化较大的情况下也能维持稳定的查找性能,适用于可变长地址的路由查找转发。
文摘针对IP路由器的FIB(Forwarding Information Base)极限问题和分布式IP地址查找中的通信延迟问题,提出了SD-Torus(Semi-Diagonal Torus)直连网络。按照"临近存储"的原则,将路由表划分后存储在每个节点及其邻居节点上,以减少分布式IP地址查找中的通信延迟,提高整体的查找性能。在分析SD-Torus网络拓扑性质的基础上,提出了一种负载均衡的路由算法。基于SystemC的仿真结果表明,使用该结构可以大大降低分布式IP地址查找的通信延迟,提高系统的扩展性。该研究结果可以应用于高性能的分布式IP地址查找。
基金the National Natural Science Foundation of China (No.60532030).
文摘The feature of Ternary Content Addressable Memories(TCAMs) makes them particularly attractive for IP address lookup and packet classification applications in a router system. However,the limitations of TCAMs impede their utilization. In this paper,the solutions for decreasing the power consumption and avoiding entry expansion in range matching are addressed. Experimental results demonstrate that the proposed techniques can make some big improvements on the performance of TCAMs in IP address lookup and packet classification.
