公开(公告)号：US07206862B2

公开(公告)日：2007-04-17

申请号：US10128919

申请日：2002-04-24

Applicant: Graham A. Wheeler

Inventor： Graham A. Wheeler

IPC: G06F15/16

CPC classification number: H04L63/10 ,  H04L63/1466 ,  H04L67/104

Abstract: A method and system are disclosed for efficiently matching incoming packets to previously forwarded outgoing packets within a network node to ensure a response received by a network node corresponds to a previously forwarded request. The network node receives an outgoing packet including state information and computes a mapping (e.g., hash) function value based upon the state information. Thereafter, the network node sets and entry within a bitmap at a position corresponding to the mapping function value. The network node also receives an incoming packet purportedly responsive to an earlier outgoing packet and includes state information of a type corresponding to the state information of an outgoing packet. The network node computes a mapping function value based upon the state information in the incoming packet. The network node then tests an entry corresponding to the mapping function value within one or more bitmaps including bits set at positions corresponding to previously forwarded outgoing packets. If the corresponding bit is not set within at least one of the bitmaps, then the network node discards the corresponding packet. Finally, in order to maintain a relative sparse bitmap, the entries are reset after detecting a clearance threshold event.

Abstract translation: 公开了一种方法和系统，用于将进入的分组有效地匹配到网络节点内的先前转发的输出分组，以确保由网络节点接收的响应对应于先前转发的请求。 网络节点接收包括状态信息的输出分组，并根据状态信息计算映射（例如散列）函数值。 此后，网络节点在对应于映射函数值的位置处设置和输入位图。 网络节点还接收据称响应于较早输出分组的传入分组，并且包括与输出分组的状态信息对应的类型的状态信息。 网络节点根据进入的分组中的状态信息来计算映射函数值。 网络节点然后在一个或多个位图中测试与映射函数值相对应的条目，包括在与先前转发的输出分组相对应的位置处设置的比特。 如果对应的位未设置在至少一个位图中，则网络节点丢弃相应的数据包。 最后，为了保持相对稀疏的位图，在检测到清除阈值事件之后，条目被重置。