Cisco Technology, Inc.

Silicon Graphics, Incorporated

Daniel R Ullum

David Walker

Thomas James Edsall

Silvano Gai

Philip R Manela

Soei-Shin Hang

Yichou Lin

Christina Hien Tran

John C Lin

Peter R Birch

Yan-ming Chen

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.

Traffic monitor using leaky bucket with variable fill

A network traffic shaper provides high-speed, multi-level shaping. The traffic shaper is in communicating relationship with a forwarding engine, and includes a queue controller having a plurality of queues for storing messages, a scheduler for computing release times, at least one time-searchable memory and a corresponding memory controller. Each queue is preferably associated with a corresponding traffic specifier, and a release time is computed for each queue and stored in the time-searchable memory. When a stored release time expires, the message at the head of the corresponding queue is retrieved and is either moved into a different queue or forwarded by the network device. By moving messages through two or more queues, each having its own release time computed in response to a different traffic specifier, the traffic shaper can perform multi-level shaping on network messages.

Method and apparatus for performing high-speed traffic shaping

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.

Network switch with hash table look up

A method of gaining access to multiple signals internal to a semiconductor chip while minimizing the number of pins dedicated for diagnostic and testing purposes. A chip designer determines which internal signals would most likely be helpful in troubleshooting and debugging a new chip design. These signals are input to a selector. A configuration register is loaded with information specifying which ones of these signals is to be routed to the output pin(s) so that they can be monitored externally by a logic analyzer in real-time. The selector only routes the currently designated signals to the appropriate output pin(s). Subsequently, a different set of signals can be selectively routed to the output pin(s) in place of the originally chosen signals.

Output pin for selectively outputting one of a plurality of signals

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San Jose, CA, United States of America

Daniel R Ullum