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
An internal structure of Ternary Content Addressable Memory (TCAM) is designed and a Sorting Prefix Block (SPB) algorithm is presented, which is a wire-speed routing lookup algorithm based on TCAM. SPB algorithm makes...An internal structure of Ternary Content Addressable Memory (TCAM) is designed and a Sorting Prefix Block (SPB) algorithm is presented, which is a wire-speed routing lookup algorithm based on TCAM. SPB algorithm makes use of the parallelism of TCAM adequately, and improves the utilization of TCAM by optimum partitions. With the aid of effective management algorithm and memory image, SPB separates critical searching from assistant searching, and improves the searching effect. One performance test indicates that this algorithm can work with different TCAM to meet the requirement of wire-speed routing lookup.展开更多
Packet classification (PC) has become the main method to support the quality of service and security of network application. And two-dimensional prefix packet classification (PPC) is the popular one. This paper analyz...Packet classification (PC) has become the main method to support the quality of service and security of network application. And two-dimensional prefix packet classification (PPC) is the popular one. This paper analyzes the problem of ruler conflict, and then presents a TCAMbased two-dimensional PPC algorithm. This algorithm makes use of the parallelism of TCAM to lookup the longest prefix in one instruction cycle. Then it uses a memory image and associated data structures to eliminate the conflicts between rulers, and performs a fast two-dimensional PPC.Compared with other algorithms, this algorithm has the least time complexity and less space complexity.展开更多
PIM-SM(Protocol Independent Multicast-Sparse Mode) is a main multicast routing pro-tocol in the IPv6(Internet Protocol version 6).It can use either a shared tree or a shortest path tree to deliver data packets,consequ...PIM-SM(Protocol Independent Multicast-Sparse Mode) is a main multicast routing pro-tocol in the IPv6(Internet Protocol version 6).It can use either a shared tree or a shortest path tree to deliver data packets,consequently the multicast IP lookup engine requires,in some cases,two searches to get a correct lookup result according to its multicast forwarding rule,and it may result in a new requirement of doubling the lookup speed of the lookup engine.The ordinary method to satisfy this requirement in TCAM(Ternary Content Addressable Memory) based lookup engines is to exploit parallelism among multiple TCAMs.However,traditional parallel methods always induce more re-sources and higher design difficulty.We propose in this paper a novel approach to solve this problem.By arranging multicast forwarding table in class sequence in TCAM and making full use of the intrinsic characteristic of the TCAM,our approach can get the right lookup result with just one search and a single TCAM,while keeping the hardware of lookup engine unchanged.Experimental results have shown that the approach make it possible to satisfy forwarding IPv6 multicast packets at the full link rate of 20 Gb/s with just one TCAM with the current TCAM chip.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An internal structure of Ternary Content Addressable Memory (TCAM) is designed and a Sorting Prefix Block (SPB) algorithm is presented, which is a wire-speed routing lookup algorithm based on TCAM. SPB algorithm makes use of the parallelism of TCAM adequately, and improves the utilization of TCAM by optimum partitions. With the aid of effective management algorithm and memory image, SPB separates critical searching from assistant searching, and improves the searching effect. One performance test indicates that this algorithm can work with different TCAM to meet the requirement of wire-speed routing lookup.
基金Foundation item: supported by Intel Corporation (No. 9078)
文摘Packet classification (PC) has become the main method to support the quality of service and security of network application. And two-dimensional prefix packet classification (PPC) is the popular one. This paper analyzes the problem of ruler conflict, and then presents a TCAMbased two-dimensional PPC algorithm. This algorithm makes use of the parallelism of TCAM to lookup the longest prefix in one instruction cycle. Then it uses a memory image and associated data structures to eliminate the conflicts between rulers, and performs a fast two-dimensional PPC.Compared with other algorithms, this algorithm has the least time complexity and less space complexity.
基金Supported by the National High-Tech Research and De-velopment Plan of China (No. 2007AA01Z2a1)the Na-tional Grand Fundamental Research 973 Program of China (No. 2007CB307102)
文摘PIM-SM(Protocol Independent Multicast-Sparse Mode) is a main multicast routing pro-tocol in the IPv6(Internet Protocol version 6).It can use either a shared tree or a shortest path tree to deliver data packets,consequently the multicast IP lookup engine requires,in some cases,two searches to get a correct lookup result according to its multicast forwarding rule,and it may result in a new requirement of doubling the lookup speed of the lookup engine.The ordinary method to satisfy this requirement in TCAM(Ternary Content Addressable Memory) based lookup engines is to exploit parallelism among multiple TCAMs.However,traditional parallel methods always induce more re-sources and higher design difficulty.We propose in this paper a novel approach to solve this problem.By arranging multicast forwarding table in class sequence in TCAM and making full use of the intrinsic characteristic of the TCAM,our approach can get the right lookup result with just one search and a single TCAM,while keeping the hardware of lookup engine unchanged.Experimental results have shown that the approach make it possible to satisfy forwarding IPv6 multicast packets at the full link rate of 20 Gb/s with just one TCAM with the current TCAM chip.
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.
