Ternary content addressable memories (TCAMs) have a lookup complexity of O(1). They require just one memory access to find an entry. For this reason, they are widely used in core routers of the Internet to achieve high packet forwarding capacities in terms of several 100 Gb/s. However, in a TCAM, the routing table needs to be stored in a sorted order according to the prefix length of the entries. Therefore, if a new entry needs to be added or an old one needs to be deleted, some other entries should be moved around to open a place for the new entry or fill the place of the old one. Practical methods to update a routing table require locking the TCAM during the update process. Therefore, this will cause a large number of packets to be dropped. This is because in the core routers of the Internet, the packets arrive at very high rates, and the routing table updates are very frequent. In this paper, we introduce a new, yet simple TCAM architecture in which entries do not need to be sorted. This means that updating the routing table will be done with a complexity of O(1), and therefore, no packets will be dropped.

中文翻译：

---

更新复杂度为 O(1) 的 IP 路由的新 TCAM 架构

三元内容可寻址存储器 (TCAM) 的查找复杂度为 O(1)。它们只需要一次内存访问即可找到一个条目。因此，它们被广泛用于互联网的核心路由器中，以实现数百 Gb/s 的高数据包转发能力。但是，在TCAM中，路由表需要按照表项的前缀长度排序存储。因此，如果需要添加新条目或需要删除旧条目，则应移动一些其他条目，为新条目开辟一个位置或填补旧条目的位置。更新路由表的实用方法需要在更新过程中锁定 TCAM。因此，这将导致大量数据包被丢弃。这是因为在 Internet 的核心路由器中，数据包以非常高的速率到达，并且路由表更新非常频繁。在本文中，我们介绍了一种新的、简单的 TCAM 架构，其中不需要对条目进行排序。这意味着更新路由表的复杂度为 O(1)，因此不会丢弃任何数据包。