Intelligent adjunct network device

• US 8,755,382 B2
• Filed: 02/14/2011
• Issued: 06/17/2014
• 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: Smith, Michael R., Gourlay, Douglas Alan, Wang, Jeffrey Ym, Golshan, Ali
• Primary Examiner(s): Jiang, Charles C
• Assistant Examiner(s): KAMARA, MOHAMED A
• Application Number:
  US13/026,839
• Publication Number:
  US 20110134923A1
• Time in Patent Office: 1,219 Days
• Field of Search: 370/386, 370/392, 370/395.3, 370/400, 370/419, 370/256, 370/390, 370/389, 370/412, 370/252, 370/254
• 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 from a controlling network device via an uplink interface, wherein

the first forwarding information comprises one or more entries, and

each entry of the one or more entries comprises a destination address and an associated port identifier;

determining whether local forwarding information stored in a local forwarding table comprises a first entry of the one or more entries, wherein

the local forwarding information comprises a plurality of destination addresses and a plurality of port identifiers, and

the determining comprises comparing a first destination address of the first entry with the local forwarding information;

if the comparing indicates that the first destination address is not found in the local forwarding information

updating the local forwarding table, wherein

the updating comprises adding the first entry to the local forwarding information; and

if the comparing indicates that the first destination address is found in the local forwarding information

discarding the first entry, and

determining whether the first entry is consistent with the local forwarding information, wherein

the determining whether the first entry is consistent comprises comparing a first port identifier associated with the first entry with the local forwarding information.

2. The method of claim 1, further comprising:

sending an indication of inconsistency to the controlling network device via the uplink interface, if the first entry is not consistent with the local forwarding information.

3. The method of claim 1, further comprising:

generating the local forwarding information.

4. The method of claim 3, wherein the generating the local forwarding information comprises:

receiving a packet via a port;

detecting a source of the packet; and

storing information associating the source with the port in the local forwarding table.

5. The method of claim 1, further comprising:

forwarding a packet from a first port on an adjunct network device to a second port on the adjunct network device using the local forwarding information, wherein

the forwarding prevents the packet from being transmitted to the controlling network device via the uplink interface.

6. The method of claim 1, wherein

the receiving is performed in response to at least one of detecting expiration of a predetermined time period, or

detecting a state transition to online.

7. The method of claim 4, further comprising:

sending the packet to the uplink interface; and

appending a header to the packet before the packet is sent to the uplink interface, wherein

the header comprises a first port identifier associated with the first port, and

the first port identifier was specified by the controlling network device.

21. The method of claim 1, wherein

the first forwarding information is received at an intelligent adjunct network device from a controlling network device, and

the controlling network device is configured to be coupled between a plurality of intelligent adjunct network devices and a core network layer and to aggregate information flows from the intelligent adjunct network devices to the core network layer.

8. A system comprising:

an uplink interface configured to receive first forwarding information from a controlling network device, wherein

the first forwarding information comprises one or more entries, and

each entry of the one or more entries comprises a destination address and an associated port identifier; and

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

determine whether local forwarding information stored in a local forwarding table comprises a first entry of the one or more entries, wherein

the local forwarding information comprises a plurality of destination addresses and a plurality of port identifiers, and

determining whether local forwarding information stored in a local forwarding table comprises a first entry of the one or more entries comprises comparing a first destination address of the first entry with the local forwarding information;

if the comparing indicates that the first destination address is not found in the local forwarding information, update the local forwarding table, wherein

updating the local forwarding table comprises adding the first entry to the local forwarding information; and

if the comparing indicates that the first destination address is found in the local forwarding information

discard the first entry, and

determine whether the first entry is consistent with the local forwarding information, wherein

determining whether the first entry is consistent comprises comparing a first port identifier associated with the first entry with the local forwarding information.

9. The system of claim 8, wherein the adjunct forwarding engine is further configured to:

send an indication of inconsistency to the controlling network device via the uplink interface, if the first entry is not consistent with the local forwarding information.

10. The system of claim 8, wherein the adjunct forwarding engine is further configured to:

generate the local forwarding information.

11. The system of claim 10, wherein generating the local forwarding information comprises:

receiving a packet via a port coupled to the adjunct forwarding engine;

detecting a source of the packet; and

storing information associating the source with the port in the local forwarding table.

12. The system of claim 8, wherein the adjunct forwarding engine is further configured to:

forward a packet from a first port on the adjunct network device to a second port on the adjunct network device using the local forwarding information, wherein

forwarding the packet prevents the packet from being transmitted to the controlling network device via the uplink interface.

13. The system of claim 8, wherein the uplink interface is further configured to receive the forwarding information in response to at least one of:

expiration of a predetermined time period, or

a state transition to online.

14. The system of claim 8, wherein the adjunct forwarding engine is further configured to:

send the packet to the uplink interface; and

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

the header comprises a first port identifier associated with the first port, and

the first port identifier was specified by the controlling network device.

15. A non-transitory computer readable storage medium comprising program instructions executable to:

receive first forwarding information from a controlling network device via an uplink interface, wherein

the first forwarding information comprises one or more entries, and

each entry of the one or more entries comprises a destination address and an associated port identifier;

determine whether local forwarding information stored in a local forwarding table comprises a first entry of the one or more entries, wherein

the local forwarding information comprises a plurality of destination addresses and a plurality of port identifiers, and

determining whether local forwarding information stored in a local forwarding table comprises a first entry of the one or more entries comprises comparing a first destination address of the first entry with the local forwarding information;

if the comparing indicates that the first destination address is not found in the local forwarding information, update the local forwarding table, wherein

updating the local forwarding table comprises adding the first entry to the local forwarding information; and

if the comparing indicates that the first destination address is found in the local forwarding information

discard the first entry, and

determine whether the first entry is consistent with the local forwarding information, wherein

determining whether the first entry is consistent comprises comparing a first port identifier associated with the first entry with the local forwarding information.

16. The non-transitory computer readable storage medium of claim 15, wherein the instructions are further executable to:

send an indication of inconsistency to the controlling network device via the uplink interface, if the first entry is not consistent with the local forwarding information.

17. The non-transitory computer readable storage medium of claim 15, wherein the instructions are further executable to:

generate the local forwarding information.

18. The non-transitory computer readable storage medium of claim 17, wherein the instructions are further executable to:

receive a packet via a port;

detect a source of the packet; and

store information associating the source with the port in the local forwarding table.

19. The non-transitory computer readable storage medium of claim 15, wherein the instructions are further executable to:

forward a packet from a first port on an adjunct network device to a second port on the adjunct network device using the local forwarding information, wherein

forwarding the packet prevents the packet from being transmitted to the controlling network device via the uplink interface.

20. The non-transitory computer readable storage medium of claim 18, wherein the instructions are further executable to:

send the packet to the uplink interface; and

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

the header comprises a first port identifier associated with the first port, and

the first port identifier was specified by the controlling network device.