Redundant packet routing and switching device and method

• US 7,525,904 B1
• Filed: 04/14/2003
• Issued: 04/28/2009
• Est. Priority Date: 06/20/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Li, Anthony J., Barnes, Peter M., Lynch, William L.
• Primary Examiner(s): Chan; Wing F.
• Assistant Examiner(s): Mais; Mark A.
• Application Number:
  US10/414,133
• Time in Patent Office: 2,206 Days
• Field of Search: 370235-238, 370/238.1, 370/389, 370/390, 370/392, 370/395.1, 370/396, 370/395.21, 370/395.31, 370/411, 370/431, 370/432, 370474-476
• US Class Current: 370/217
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 49/252 Store and forward routing
• CPC Class Codes: H04L 49/3072 Packet splitting
• CPC Class Codes: H04L 49/552 by ensuring the integrity of packets received through redundant connections

Abstract

A router and method therefore for routing and switching a packet from an incoming link to an outgoing link. The router may include a plurality of network processing units, a plurality of switching engines, and a plurality of connections between the plurality of network processing units and the plurality of switching engines defining a rotational symmetric topology. The router may also include a means for connecting the plurality of network processing units to the plurality of switching engines, as well as means for connecting the plurality of switching engines to the plurality of line card units. In one example, the plurality of line card units is connected with the plurality of switching engines in a full mesh topology.

Claims

1. A method of routing and switching a packet from an incoming link to an outgoing link in a router with redundancy comprising:

providing at least one network processing unit to perform routing operations and to determine an outgoing link to transmit the packet based on information in a header of the packet, the at least one network processing unit being connected with at least one active switching engine and at least one inactive switching engine, wherein a transmission of packets is mapped from the at least one network processing unit to the at least one active switching engine, the outgoing link being determined prior to dividing the data packet into a plurality of cells and storing the plurality of cells in a memory of the at least one active switching engine;

activating one of the at least one inactive switching engines, when any active switching engine discontinues operating normally, and rotating the active inputs of the switching engine that has discontinued operating normally to the activated one of the at least one inactive switching engines; and

remapping the transmission of packets to the activated at least one inactive switching engine.

2. The method of claim 1, further comprising:

inactivating one of the at least one active switching engines.

3. The method of claim 1, wherein the operation of remapping further comprises:

rotating the transmission of packets from the inactivated one of the at least one active switching engines to the activated one of the at least one inactive switching engines.

4. A method comprising:

receiving a data packet, the data packet having a header including information indicative of a packet destination;

determining a destination port associated with the data packet, the destination port being determined based on information in the packet header, the destination port being determined prior to dividing the data packet into a plurality of cells and storing the plurality of cells in a switching engine memory;

assigning an output queue to the data packet, the output queue being associated with the destination port;

activating at least one inactive switching engine, when an active switching engine discontinues operating normally;

mapping the data packet to an active switching engine;

dividing the data packet into a plurality of cells;

storing the plurality of cells contiguously in the output queue; and

re-assembling the plurality of cells into the data packet and transmitting the data packet to the packet destination via the destination port.

5. The method as claimed in claim 4 including performing a forwarding table lookup prior to dividing the data packet into a plurality of cells and storing the plurality of cells in a switching engine memory.

6. The method as claimed in claim 4 including determining when any active switching engine discontinues operating normally.

7. The method as claimed in claim 4 including rotating connections to a different switching engine, when any active switching engine discontinues operating normally.

8. The method as claimed in claim 4 including determining a number of available line card units.

9. The method as claimed in claim 4 including remapping the assigned output queue to account for a reduced number of available line card units.

10. A router comprising:

a network processing unit to receive a data packet, the data packet having a header including information indicative of a packet destination, the network processing unit to determine a destination port associated with the data packet, the destination port being determined based on information in the packet header, the destination port being determined prior to dividing the data packet into a plurality of cells and storing the plurality of cells in a switching engine memory, the network processing unit to assign an output queue to the data packet, the output queue being associated with the destination port, to activate at least one inactive switching engine, when an active switching engine discontinues operating normally, and to map the data packet to an active switching engine;

a switching engine to divide the data packet into a plurality of cells, the switching engine to store the plurality of cells contiguously in the output queue; and

a line card unit to re-assemble the plurality of cells into the data packet and to transmit the data packet to the packet destination via the destination port.

11. The router as claimed in claim 10 wherein the network processing unit being further configured to perform a forwarding table lookup prior to the data packet being divided into a plurality of cells and the plurality of cells being stored in the output queue.

12. The router as claimed in claim 10 being further configured to determine when any active switching engine discontinues operating normally.

13. The router as claimed in claim 10 being further configured to rotate connections to a different switching engine, when any active switching engine discontinues operating normally.

14. The router as claimed in claim 10 being further configured to determine a number of available line card units.

15. The router as claimed in claim 10 being further configured to remap the assigned output queue to account for a reduced number of available line card units.