Pub Date : 2024-08-07DOI: 10.1109/TVLSI.2024.3436047
Xiaoyong Song;Zhichuan Guo
Match table is the key part to perform packet processing and forwarding for programmable switches in a software-defined network (SDN). However, the match table in current field-programmable gate array (FPGA)-based switches is inflexible or undisclosed. When the network function changes, the match table on FPGA needs to be redesigned or reset size parameters, and after recompilation and reimplementation, it could work again; this time-consuming and labor-intensive operation seriously reduces the flexibility and configurability of the switch. To address this issue, this article presents a design of reconfigurable match table (RMT) for FPGA-based programmable switches. A three-layer table structure is introduced to realize the reconfiguration and hardware-plane mapping of user-defined tables, and the logical tables in packet processing pipeline are interconnected with the physical tables in memory pool by the designed resource-efficient segment crossbar. To the best of our knowledge, this article is the first to publicly present the entire FPGA-based RMT design scheme and implementation details. The proposed design implements reconfigurable ternary content addressable memory (TCAM) based and static random access memory (SRAM) based match tables on Xilinx FPGA and verifies them with a packet filter system. In the proposed RMT system, a user could reconfigure the number, depth, and width of user-defined match tables (UMTs) in pipeline via control plane without modifying hardware, which enhances the flexibility of the data plane of FPGA-based switch greatly.
{"title":"An Implementation of Reconfigurable Match Table for FPGA-Based Programmable Switches","authors":"Xiaoyong Song;Zhichuan Guo","doi":"10.1109/TVLSI.2024.3436047","DOIUrl":"10.1109/TVLSI.2024.3436047","url":null,"abstract":"Match table is the key part to perform packet processing and forwarding for programmable switches in a software-defined network (SDN). However, the match table in current field-programmable gate array (FPGA)-based switches is inflexible or undisclosed. When the network function changes, the match table on FPGA needs to be redesigned or reset size parameters, and after recompilation and reimplementation, it could work again; this time-consuming and labor-intensive operation seriously reduces the flexibility and configurability of the switch. To address this issue, this article presents a design of reconfigurable match table (RMT) for FPGA-based programmable switches. A three-layer table structure is introduced to realize the reconfiguration and hardware-plane mapping of user-defined tables, and the logical tables in packet processing pipeline are interconnected with the physical tables in memory pool by the designed resource-efficient segment crossbar. To the best of our knowledge, this article is the first to publicly present the entire FPGA-based RMT design scheme and implementation details. The proposed design implements reconfigurable ternary content addressable memory (TCAM) based and static random access memory (SRAM) based match tables on Xilinx FPGA and verifies them with a packet filter system. In the proposed RMT system, a user could reconfigure the number, depth, and width of user-defined match tables (UMTs) in pipeline via control plane without modifying hardware, which enhances the flexibility of the data plane of FPGA-based switch greatly.","PeriodicalId":13425,"journal":{"name":"IEEE Transactions on Very Large Scale Integration (VLSI) Systems","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141939169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1109/TVLSI.2024.3436575
Mehdi Saberi;Hossein Yaghoobzadeh Shadmehri;Mohammad Tavakkoli Ghouchani;Alexandre Schmid
This brief proposes a low-voltage, high-precision, and high-dynamic-range current-mode analog winner-take-all (WTA) circuit. The proposed structure employs a new high-gain stage as a feedback network between the input node of each cell and the common node of the circuit to reduce the sensitivity of the output current to the loser signals, especially when they are close to the winner. In addition, another network is employed that senses the amount of the output/winner current and adjusts the bias current of the gain stages. This ensures that the drain-source voltage of the input transistor in the winner cell matches the behavior of the output transistor’s drain-source voltage, enhancing the accuracy as well as the input dynamic range (DR) of the structure. Moreover, since the circuit works properly with a minimum supply voltage of only $V_{text {GS}} + V_{text {eff}}$