Thomas J Edsall

6457058, Sep 24, 2002

Jul 12, 2001

09/904431

Daniel Ullum - San Jose CA
Thomas J. Edsall - Mountain View CA

Cisco Technology, Inc. - San Jose CA

G06F 15173

709238, 709245

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 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.

6643260, Nov 4, 2003

Dec 18, 1998

09/213105

Raymond J. Kloth - Mountain View CA
Thomas J. Edsall - Cupertino CA
Michael Fine - San Francisco CA
Dinesh G. Dutt - Santa Clara CA

Cisco Technology, Inc. - San Jose CA

G01R 3108

370235, 370412

A content addressable memory (CAM or L3 Table) contains flow information for each active flow of packets passing through a given node of a data communications network. The CAM has associated with each entry (corresponding to each active flow) a packet counter, a byte counter, a token bucket and a contract value. Each flow is assigned one of a plurality of output queues and optionally at least one output threshold value. A token bucket algorithm is employed on each flow to determine whether packets from that flow exceed the contract value. Such packets may be dropped or optimally modified to reflect an alternate output queue and/or alternate threshold before being sent to the selected output queue for transmission from the node. In another aspect an access control list CAM (ACLCAM) contains masked flow information. The ACLCAM provides an index to internal token bucket counters and preconfigured contract values of an aggregate flow table which becomes affected by the packet statistics.

6675220, Jan 6, 2004

Aug 11, 1999

09/372480

Davide Bergamasco - San Jose CA
Thomas J. Edsall - Cupertino CA
Guglielmo M. Morandin - Milpitas CA
Keith McCloghrie - San Jose CA

Cisco Technology, Inc. - San Jose CA

G06F 1516

709232, 709233, 709234, 709235

Techniques for managing queues of packets are provided. Once the average queue size crosses a minimum threshold, packets are dropped according to a probability. Once a packet is dropped, the minimum threshold is increased in order to decrease the likelihood that a subsequent packet will be dropped. As packets are accepted, the minimum threshold is decreased gradually to its original value so that the distribution of dropped packets is very uniform.

6714985, Mar 30, 2004

Apr 28, 2000

09/561839

Dante Malagrino - Santa Clara CA
Thomas J. Edsall - Cupertino CA
Silvano Gai - San Jose CA

Cisco Technology, Inc. - San Jose CA

G06F 1516

709236, 370394

An IP packet reassembly engine provides high-speed and efficient reassembly of IP fragments received at an intermediate station in a computer network. The IP packet reassembly engine comprises a main controller logic circuit configured to âspeed-upâ re-assembly of original packets from IP fragments stored in a frame buffer at multi-gigabit per second rates. To that end, the reassembly engine further includes a content addressable memory having a plurality of entries for maintaining status information for each received fragment and for each original packet being reassembled from the fragments.

6735198, May 11, 2004

Dec 21, 1999

09/469062

Thomas J. Edsall - Cupertino CA
Herman Levenson - Palo Alto CA
Claudette Lucille Surma - Fremont CA
Ajit Sanzgiri - Cupertino CA
Saravanakumar Rajendran - San Jose CA
Tuan Thanh Nguyen - Milpitas CA

Cisco Technology, Inc. - San Jose CA

H04L 1228

370389, 370401, 370469, 370512

A mechanism and technique updates and synchronizes forwarding tables contained on line cards that are interconnected by a switch fabric of a distributed network switch. The network switch is preferably a L3 or L4 switch comprising a plurality of forwarding engines distributed among the line cards. Each forwarding engine has an associated forwarding table, which preferably includes a L2 portion and L3/L4 portions. The L2 portion of the table is used to execute forwarding decision operations for frames forwarded among ports of the line cards, whereas the L3/L4 portions of the table are used to execute shortcut and forwarding operations for frames routed among the ports. The mechanism comprises a media access control (MAC) notification (MN) frame for updating and synchronizing the location of a destination port stored in the L2 portions of the forwarding tables.

6735201, May 11, 2004

Sep 10, 2002

10/238422

Umesh Mahajan - Fremont CA
Ramana Mellacheruvu - Sunnyvale CA
Thomas J. Edsall - Mountain View CA
Raymond Kloth - Mountain View CA

Cisco Technology, Inc. - San Jose CA

H04L 1228

370390

Efficient switched network multicasting techniques are provided. Incoming multicast packets are processed by a central forwarding engine (CFE) in a network switch to generate forwarding indices used to make forwarding decisions for the packets based upon whether the packets are special multicast control packets or data packets. Forwarding of the special multicast control packets is determined by the switchs network management processor (NMP), while data packets are forwarded based upon conventional bridge forwarding techniques.

6741592, May 25, 2004

May 22, 2000

09/575774

Thomas J. Edsall - Cupertino CA
Michael Fine - San Francisco CA
Thomas Nosella - Sunnyvale CA

Cisco Technology, Inc. - San Jose CA

G06F 15173

370389, 370401, 709225

The invention uses a layer switch (L switch), or bridge, to separate users message traffic by use of Virtual Local Area Networks (VLANs) defined within the switch. Three new types of ports are defined, âpromiscuousâ ports âisolatedâ ports, and âcommunityâ ports. Three types of VLANs internal to the switch are defined, âprimaryâ VLANs, âisolatedâ VLANs and âcommunityâ VLANs. The promiscuous ports are connected to layer or layer devices. Isolated ports and community ports are connected to individual users servers, etc. , and maintain traffic for each user separate from other users. The primary VLAN connects to all promiscuous ports, to all isolated ports, and to all community ports. The primary VLAN is a one way connection from promiscuous ports to isolated or community ports. An isolated VLAN connects to all promiscuous ports and to all isolated ports.

6762675, Jul 13, 2004

Sep 27, 1999

09/406248

Luca Cafiero - Palo Alto CA
Maurilio De Nicolo - Saratoga CA
Thomas Edsall - Cupertino CA
Karl Nakamura - Palo Alto CA

Cisco Technology, Inc. - San Jose CA

H04Q 522

340 1042, 34031001, 379 2201, 713300, 713310

A network node determines the suitability of coupled devices for being remotely line powered before actually powering them. The node scan its ports to determine which ports are coupled to devices. The node then interrogates the coupled devices. A unique discovery tone or bit pattern is generated and sent to devices coupled to ports. The node then monitors the port for a return signal. If there is a return signal, it is compared to the transmitted discovery signal. The signal will be identical after allowing for line losses if the coupled device is suitable for remote line powering. If the comparison yields a match, the network node supplies remote line power to the device.