Nortel Networks Corporation

Bay Networks, Inc.

Jeffrey Prince

Randy Ryals

Mike K Noll

Derek H Pitcher

H Earl Ferguson

A method and apparatus for managing the flow of data within a switching device is provided. The switching device includes network interface cards connected to a common backplane. Each interface card is configured to support the maximum transfer rate of the backplane by maintaining a 'pending' queue to track data that has been received but for which the appropriate routing destination has not yet been determined. The switching device includes a switch controller that maintains a central card/port-to-address table. When an interface card receives data with a destination address that is not known to the interface card, the interface card performs a direct memory access over a bus that is separate from the backplane to read routing data directly from the central table in the switch controller. Each interface card builds and maintains a routing information table in its own local memory that only includes a routing information for the destination addresses that the interface card is most likely to receive.

Method and apparatus for managing the flow of data within a switching device

A method and apparatus for managing the flow of data within a switching device is provided. The switching device includes network interface cards connected to a common backplane. Each interface card is configured to support the maximum transfer rate of the backplane by maintaining a 'pending' queue to track data that has been received but for which the appropriate routing destination has not yet been determined. The switching device includes a switch controller that maintains a central card/port-to-address table. When an interface card receives data with a destination address that is not known to the interface card, the interface card performs a direct memory access over a bus that is separate from the backplane to read routing data directly from the central table in the switch controller. Each interface card builds and maintains a routing information table in its own local memory that only includes routing information for the destination addresses that the interface card is most likely to receive.

A method and apparatus for managing the flow of data within a switching device is provided. The switching device includes network interface cards connected to a common backplane. Each interface card is configured to support the maximum transfer rate of the backplane by maintaining a &ldquo;pending&rdquo; queue to track data that has been received but for which the appropriate routing destination has not yet been determined. The switching device includes a switch controller that maintains a central card/port-to-address table. When an interface card receives data with a destination address that is not known to the interface card, the interface card performs a direct memory access over a bus that is separate from the backplane to read routing data directly from the central table in the switch controller. Each interface card builds and maintains a routing information table in its own local memory that only includes routing information for the destination addresses that the interface card is most likely to receive.

A method and apparatus for controlling data flow within a switching device are provided. The switching device includes a cell-switched backplane. Both packet switched and cell switched network interface cards may be coupled to the cell-switched backplane. A destination tag is created for each unique destination port and for each unique set of destination ports. The destination tags are used to index a master destination tag table. The entry of the master destination tag table that corresponds to a given destination tag includes a destination mask that indicates which ports are destination ports the given destination tag. Local tables are built and maintained within each network interface card based on the information contained in the master destination tag table. When a network interface receives data from an external device, the network interface determines the destination tag associated with the data. Once the destination tag is determined, it is used as an index to the locally stored tables to determine whether the data should be forwarded to any local ports, and whether the data should be sent over the cell-switched backplane to other network interfaces within the switching device. When a network interface receives data over the backplane, the network interface uses the destination tag as an index to a locally stored table to determine to which local ports the data should be sent. Tables also establish correlations between destination tags and control information for converting data between packets and cells.

Growing community of inventors

Sunnyvale, CA, United States of America

Jeffrey Prince