Intelligent adjunct network device

• US 7,889,733 B2
• Filed: 04/28/2004
• Issued: 02/15/2011
• Est. Priority Date: 04/28/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Gourlay, Douglas Alan, Wang, Jeffrey Y M, Golshan, Ali, Smith, Michael R.
• Primary Examiner(s): Patel; Jayanti K
• Assistant Examiner(s): Sol; Anthony
• Application Number:
  US10/833,377
• Publication Number:
  US 20050243826A1
• Time in Patent Office: 2,484 Days
• Field of Search: None
• US Class Current: 370/392
• CPC Class Codes: H04L 12/08 Allotting numbers to messages; Counting characters, words or messages
• CPC Class Codes: H04L 12/2854 Wide area networks, e.g. public data networks
• CPC Class Codes: H04L 41/04 Network management architectures or arrangements
• CPC Class Codes: H04L 41/0813 characterised by the conditions triggering a change of settings
• CPC Class Codes: H04L 41/082 the condition being updates or upgrades of network functionality
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 47/10 Flow control; Congestion control

Abstract

An adjunct network device includes several ports, an uplink interface, and an adjunct forwarding engine coupled to the ports and the uplink interface. A first port is configured to receive a packet, which includes a destination address. The adjunct forwarding engine is configured to send the packet to the uplink interface if the destination address is not associated with any of the ports. The packet is sent to one of the ports if the destination address is associated with the one of the ports.

Claims

1. A method comprising:

receiving first forwarding information via an uplink interface;

storing the first forwarding information in a local forwarding table;

receiving a packet via a first port of a plurality of ports, wherein

the packet comprises a destination address, and

the uplink interface is different from the plurality of ports;

determining whether the destination address corresponds to any of the plurality of ports, wherein the determining is based, at least in part, on the local forwarding table;

in response to determining the destination address does not correspond to any of the plurality of ports, based at least in part on the local forwarding table, sending the packet and additional information associated with the packet to the uplink interface;

receiving second forwarding information via the uplink interface, wherein the second forwarding information comprises results of a table lookup;

comparing the second forwarding information with forwarding information stored in the local forwarding table; and

sending an error notification to the uplink interface in response to detecting a conflict between the forwarding information stored in the local forwarding table and the second forwarding information.

2. The method of claim 1, further comprising:

if the destination address corresponds to one of the ports, sending the packet to the one of the ports.

3. The method of claim 1, wherein the error notification comprises information, the information indicating a correct value of the forwarding information.

4. The method of claim 1, further comprising:

downloading routing information to a forwarding engine via the uplink interface.

5. The method of claim 1, further comprising:

receiving a second packet via the first port, the second packet comprising a multicast destination address; and

sending a copy of the second packet to one or more of the ports.

6. The method of claim 5, further comprising:

sending an additional copy of the second packet to the uplink interface.

7. The method of claim 1, further comprising:

receiving a second packet via the first port, the second packet comprising an unknown destination address; and

flooding the second packet, wherein the flooding comprises;

sending a copy of the second packet to the uplink interface and to one or more of the ports.

8. A method comprising:

receiving first forwarding information via an uplink interface wherein the uplink interface is coupled to a virtual link bundle;

storing the first forwarding information in a local forwarding table;

receiving a packet via a first port of a plurality of ports, wherein

the packet comprises a destination address, and

the uplink interface is different from the plurality of ports;

determining whether the destination address corresponds to any of the plurality of ports, wherein the determining is based, at least in part, on the local forwarding table;

in response to determining the destination address does not correspond to any of the plurality of ports, based at least in part on the local forwarding table, sending the packet and additional information associated with the packet to the uplink interface, wherein

the additional information identifies the first port;

receiving the packet sent via the uplink interface at a virtual network device; and

preventing the packet from subsequently being sent from the virtual network device via the virtual link bundle.

9. The method of claim 8, wherein

the additional information comprises a destination identifier generated by performing a lookup for the destination address.

10. A system comprising:

a plurality of ports, wherein a first port of the ports is configured to receive a packet comprising a destination address;

an uplink interface, wherein

the uplink interface is different from the plurality of ports; and

an adjunct forwarding engine coupled to the ports and the uplink interface, wherein the adjunct forwarding engine is configured to;

receive first forwarding information via the uplink interface;

store the first forwarding information in a local forwarding table;

determine whether the destination address is associated with any of the plurality of ports, wherein the determining is based, at least in part, on the local forwarding table;

send the packet and additional information associated with the packet to the uplink interface in response to determining the destination address is not associated with any of the ports;

receive second forwarding information via the uplink interface, wherein the second forwarding information comprises results of a table lookup;

compare the second forwarding information with forwarding information stored in the local forwarding table; and

send an error notification to the uplink interface in response to detecting a conflict between the forwarding information stored in the local forwarding table and the second forwarding information.

11. The system of claim 10, wherein

the packet is sent to one of the ports if the destination address is associated with the one of the ports.

12. The system of claim 10, further comprising:

a controller configured to append a header to the packet before the packet is sent to the uplink interface, wherein

the header comprises information identifying the first port.

13. The system of claim 12, wherein the header comprises a destination identifier generated by performing a lookup for the destination address.

14. The system of claim 10, wherein

the error notification comprises information, the information indicating a correct value of the forwarding information.

15. The system of claim 10, wherein

the adjunct forwarding engine is configured to download forwarding information via the uplink.

16. The system of claim 10,

wherein

the additional information identifies the first port.

17. The system of claim 16, wherein the additional information comprises a destination identifier generated by performing a lookup for the destination address.

18. The system of claim 16, further comprising:

an uplink coupled to the uplink interface, wherein the uplink is comprised in a virtual link bundle.

19. The system of claim 10, wherein

the destination address comprises a multicast destination address;

and

the adjunct forwarding engine is configured to send a copy of the packet to one or more of the ports.

20. The system of claim 19, wherein

the adjunct forwarding engine is configured to send an additional copy of the packet via the uplink interface.

21. The system of claim 10, wherein

the adjunct forwarding engine is configured to flood the packet, wherein flooding the packet comprises:

sending a copy of the packet to each of the uplink interface and one or more of the ports.

22. A system comprising:

a plurality of ports, wherein a first port of the ports is configured to receive a packet comprising a destination address;

an uplink interface, wherein

the uplink interface is different from the plurality of ports;

an adjunct forwarding engine coupled to the ports and the uplink interface, wherein the adjunct forwarding engine is configured to;

receive first forwarding information via the uplink interface;

store the first forwarding information in a local forwarding table;

determine whether the destination address is associated with any of the plurality of ports, wherein the determining is based, at least in part, on the local forwarding table; and

send the packet and additional information associated with the packet to the uplink interface in response to determining the destination address is not associated with any of the ports

an uplink coupled to the uplink interface, wherein the uplink is comprised in a virtual link bundle; and

a virtual network device coupled to the virtual link bundle, wherein

the virtual network device is configured to receive the packet via the uplink; and

the virtual network device is configured to prevent the packet from subsequently being sent via the virtual link bundle.