SYNCHRONIZING MULTICAST INFORMATION FOR LINECARDS

• US 20110228773A1
• Filed: 10/27/2010
• Published: 09/22/2011
• Est. Priority Date: 03/19/2010
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Brocade Communications Systems, Inc. (Broadcom, Inc.)
• Inventors: Pudiyapura, Ajeer S., Yeung, Wing-Keung Adam, Dholakia, Mehul
• Granted Patent: US 8,503,289 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/586 of virtual routers
• CPC Class Codes: H04L 49/201 Multicast operation; Broadcast operation
• CPC Class Codes: H04L 49/354 for supporting virtual local area networks [VLAN]

Abstract

In a network device comprising redundant management processors and one or more linecard processors situated on one or more linecards, a linecard processor maintains multicast information that is synchronized with multicast information, or a portion thereof, maintained by an active management processor. When a switchover is performed due to which a previous standby management processor becomes the new active management processor, the switchover is performed without interrupting any multicast routing services provided by the network device. For example, a switchover may be performed in order to upgrade a linecard processor to a new software version.

Claims

1. A system comprising:

a set of ports for receiving and transmitting packets;

a first processor configured to operate in an active mode, the first processor configured to perform a set of multicast routing-related functions in the active mode, the first processor configured to maintain first information, which is used by the first processor for performing the set of multicast routing-related functions; and

a linecard coupled to at least one port from the set of ports, the linecard comprising a linecard processor and a packet processor with associated one or more memories;

wherein the packet processor is configured to facilitate forwarding of multicast packets; and

wherein the linecard processor is configured to;

maintain second information in a volatile memory coupled with the linecard processor;

receive, from the first processor, a portion of the first information maintained by the first processor;

synchronize, based upon the received portion, the second information maintained by the linecard processor with the first information; and

program the packet processor and associated memories using the second information.

2. The system of claim 1 wherein the linecard processor is configured to:

load a first version of software in the volatile memory; and

perform a reboot and, after the reboot, load a second version of software in the volatile memory that is different from the first version of software.

3. The system of claim 2 wherein:

the packet processor is configured to use third information to facilitate forwarding of multicast packets;

prior to the reboot, the linecard processor is configured to store correlation information such that the correlation information is preserved across the reboot; and

after the reboot, the second processor is configured to link the second information maintained by the linecard processor with the third information used by the packet processor using the correlation information.

4. The system of claim 3 wherein the correlation information links an entry in the second information stored in the volatile memory to an entry in a memory associated with the packet processor.

5. The system of claim 1 wherein the packet processor is configured to:

extract information from a multicast packet; and

determine, based upon the extracted information, multiple ports from the set of ports to be used for forwarding the multicast packet.

6. The system of claim 1 wherein the packet processor is configured to:

extract information from a multicast packet; and

determine, based upon the extracted information, multiple virtual LANs (VLANs) associated with a port of the system to which the multicast packet is to be forwarded.

7. The system of claim 1 wherein the first information and the second information both comprise multicast routes-related information and rendezvous point-related information.

8. A network device comprising:

a set of ports for receiving and transmitting packets;

a first processor configured to operate in an active mode, the first processor configured to perform a set of multicast routing-related functions in the active mode, the first processor configured to maintain first information, which is used by the first processor for performing the set of multicast routing-related functions;

a packet processor with associated one or more memories, wherein the packet processor is configured to facilitate forwarding of multicast packets; and

a second processor, the second processor configured to;

maintain second information in a volatile memory;

receive, from the first processor, a portion of the first information maintained by the first processor;

update the second information based upon the received portion; and

program the packet processor and associated memories using the second information.

9. The network device of claim 8 wherein the second processor is configured to:

load a first version of software in the volatile memory; and

perform a reboot and, after the reboot, load a second version of software in the volatile memory that is different from the first version of software.

10. The network device of claim 9 wherein:

the packet processor is configured to use third information to facilitate forwarding of the multicast packets;

prior to the reboot, the second processor is configured to store correlation information such that the correlation information is preserved across the reboot; and

after the reboot, the second processor is configured to link the second information with the third information using the correlation information.

11. The network device of claim 10 wherein the correlation information links an entry in the second information stored in the volatile memory to an entry in a memory associated with the packet processor.

12. The network device of claim 8 wherein the packet processor is configured to:

extract information from a multicast packet; and

determine, based upon the extracted information, multiple ports from the set of ports to be used for forwarding the multicast packet.

13. The network device of claim 8 wherein the packet processor is configured to:

extract information from a multicast packet; and

determine, based upon the extracted information, multiple virtual LANs (VLANs) associated with a port of the network device to which the multicast packet is to be forwarded.

14. The network device of claim 8 wherein the first information and the second information both comprise multicast routes-related information and rendezvous point-related information.

15. A method comprising:

operating a first processor of a network device an active mode, the operating comprising performing a set of multicast routing-related functions in the active mode;

maintaining, by the first processor, first information that is used by the first processor for performing the set of multicast routing-related functions;

facilitating, by a packet processor of the network device, forwarding of multicast packets;

maintaining, by a second processor of the network device, second information in a volatile memory;

receiving, by the second processor from the first processor, a portion of the first information maintained by the first processor;

updating, by the second processor, the second information based upon the received portion; and

programming, by the second processor, the packet processor and associated memories using the second information.

16. The method of claim 15 further comprising:

loading, by the second processor, a first version of software in the volatile memory; and

rebooting the second processor; and

after the reboot, loading, by the second processor, a second version of software in the volatile memory that is different from the first version of software.

17. The method of claim 16:

wherein the facilitating comprises using third information to forward the multicast packets;

the method further comprising;

prior to the rebooting, storing, by the second processor, correlation information such that the correlation information is preserved across the reboot; and

after the rebooting, linking the second information with the third information using the correlation information.

18. The method of claim 17 wherein the linking comprises correlating an entry in the second information stored in the volatile memory to an entry in a memory associated with the packet processor.

19. The method of claim 15 wherein the facilitating comprises:

extracting information from a multicast packet; and

determining, based upon the extracted information, multiple ports of the network device to be used for forwarding the multicast packet.

20. The method of claim 15 wherein the facilitating comprises:

extracting information from a multicast packet; and

determining, based upon the extracted information, multiple virtual LANs (VLANs) associated with a port of the network device to which the multicast packet is to be forwarded.

21. The method of claim 15 wherein the first information and the second information both comprise multicast routes-related information and rendezvous point-related information.