Wide-area scaling trends require new approaches to Internet Protocol (IP) lookup, enabled by modern networking chips such as Intel Tofino, AMD Pensando, and Nvidia BlueField, which provide substantial ternary content-addressable memory (TCAM) and static random-access memory (SRAM). However, designing and evaluating scalable algorithms for these chips is challenging due to hardware-level constraints. To address this, we introduce the CRAM (CAM+RAM) lens, a framework that combines a formal model for evaluating algorithms on modern network processors with a set of optimization idioms. We demonstrate the effectiveness of CRAM by designing and evaluating three new IP lookup schemes: RESAIL, BSIC, and MashUp. RESAIL enables Tofino-2 to scale to 2.25 million IPv4 prefixes$\unicode{x2014}$likely sufficient for the next decade$\unicode{x2014}$while a pure TCAM approach supports only 250k prefixes, just 27% of the current global IPv4 routing table. Similarly, BSIC scales to 390k IPv6 prefixes on Tofino-2, supporting 3.2 times as many prefixes as a pure TCAM implementation. In contrast, existing state-of-the-art algorithms, SAIL for IPv4 and Hi-BST for IPv6, scale to considerably smaller sizes on Tofino-2.

翻译：广域网扩展趋势要求采用新的互联网协议（IP）查找方法，现代网络芯片（如Intel Tofino、AMD Pensando和Nvidia BlueField）为此提供了充足的三态内容可寻址存储器（TCAM）和静态随机存取存储器（SRAM）。然而，由于硬件层面的限制，为这些芯片设计和评估可扩展算法具有挑战性。为解决这一问题，我们提出了CRAM（CAM+RAM）透镜框架，该框架结合了用于评估现代网络处理器算法的形式化模型与一组优化范式。我们通过设计和评估三种新型IP查找方案——RESAIL、BSIC和MashUp——验证了CRAM的有效性。RESAIL使Tofino-2能够扩展至225万个IPv4前缀（可能满足未来十年需求），而纯TCAM方案仅支持25万个前缀，仅为当前全球IPv4路由表的27%。同样地，BSIC在Tofino-2上可扩展至39万个IPv6前缀，支持数量达到纯TCAM实现的3.2倍。相比之下，现有最先进算法（IPv4的SAIL和IPv6的Hi-BST）在Tofino-2上的可扩展规模明显更小。