公开(公告)号：US06457058B1

公开(公告)日：2002-09-24

申请号：US09904431

申请日：2001-07-12

申请人： Daniel Ullum ,  Thomas J. Edsall ,  Soei-Shin Hang

发明人： Daniel Ullum ,  Thomas J. Edsall ,  Soei-Shin Hang

IPC分类号： G06F15173

CPC分类号： H04L12/467 ,  H04L12/4675 ,  H04L45/00 ,  H04L45/745

摘要： An improved look up mechanism for accessing a RAM to obtain forwarding information for data frames being transported among ports of a high-performance switch is provided. The look up mechanism includes a multi-page look up table and associated hashing technique. A media access control (MAC) address and a virtual local area network (VLAN) identifier are transformed with a hash function to obtain a hash key. The hash key is an address pointing to a particular entry in the look up table. A virtual first page is also derived from the hash key, which selects a particular physical page of the look up table to be initially accessed each time that MAC address/VLAN pair is used. The look up mechanism may also be used to access a short cut table containing Layer 3 short cut information. In either case, ultimately, the likelihood is increased that a match will be found on the first RAM access, thus maintaining high-speed switch performance.

摘要翻译： 提供了一种用于访问RAM以获得在高性能交换机的端口之间传输的数据帧的转发信息的改进的查找机制。 查找机制包括多页查找表和相关联的散列技术。 媒体访问控制（MAC）地址和虚拟局域网（VLAN）标识符通过散列函数进行变换以获得散列密钥。 哈希密钥是指向查找表中特定条目的地址。 还从散列密钥派生虚拟第一页，该密钥选择每次使用MAC地址/ VLAN对时最初访问的查找表的特定物理页。 查找机制也可用于访问包含第3层快捷方式信息的快捷表。 在这两种情况下，最终增加了在第一RAM访问中发现匹配的可能性，从而保持高速开关性能。

公开(公告)号：US06266705B1

公开(公告)日：2001-07-24

申请号：US09162730

申请日：1998-09-29

申请人： Daniel Ullum ,  Thomas J. Edsall ,  Soei-Shin Hang

发明人： Daniel Ullum ,  Thomas J. Edsall ,  Soei-Shin Hang

IPC分类号： G06F15173

CPC分类号： H04L12/467 ,  H04L12/4675 ,  H04L45/00 ,  H04L45/745

摘要： An improved look up mechanism for accessing a RAM to obtain forwarding information for data frames being transported among ports of a high-performance switch is provided. The look up mechanism includes a multi-page look up table and associated hashing technique. A media access control (MAC) address and a virtual local area network (VLAN) identifier are transformed with a hash function to obtain a hash key. The hash key is an address pointing to a particular entry in the look up table. A virtual first page is also derived from the hash key, which selects a particular physical page of the look up table to be initially accessed each time that MAC address/VLAN pair is used. The look up mechanism may also be used to access a short cut table containing Layer 3 short cut information. In either case, ultimately, the likelihood is increased that a match will be found on the first RAM access, thus maintaining high-speed switch performance.

摘要翻译： 提供了一种用于访问RAM以获得在高性能交换机的端口之间传输的数据帧的转发信息的改进的查找机制。 查找机制包括多页查找表和相关联的散列技术。 媒体访问控制（MAC）地址和虚拟局域网（VLAN）标识符通过散列函数进行变换以获得散列密钥。 哈希密钥是指向查找表中特定条目的地址。 还从散列密钥派生虚拟第一页，该密钥选择每次使用MAC地址/ VLAN对时最初访问的查找表的特定物理页。 查找机制也可用于访问包含第3层快捷方式信息的快捷表。 在这两种情况下，最终增加了在第一RAM访问中发现匹配的可能性，从而保持高速开关性能。

公开(公告)号：US20060209696A1

公开(公告)日：2006-09-21

申请号：US11438857

申请日：2006-05-23

申请人： David Walker ,  Daniel Ullum

发明人： David Walker ,  Daniel Ullum

IPC分类号： H04J1/16

CPC分类号： H04L47/21 ,  H04L43/00 ,  H04L43/022 ,  H04L43/024 ,  H04L43/12 ,  H04L47/10 ,  H04L47/11 ,  H04L49/254 ,  H04L49/503 ,  H04L2012/5637 ,  H04L2012/5684

摘要： An integrated circuit monitors the most active traffic flow rates on a communications network by using a leaky bucket model having a variable fill rate. As a switch receives packets, the packet identifications are sampled. A sampled packet identification is compared to record identifications in a table of identifications. If the sampled and record identifications match, an activity value for the packet identification is increased by an amount inversely proportional to an activity value associated with the record identification. If the sampled and record identifications do not match, the activity value is decreased. Record identifications are removed from the table when the activity value decreases to a specified level. New sampled identifications are added to the table if empty records exist.