Granted Patent B2

US 10,187,293 · App. 14/861,838 · Granted Jan 22, 2019

Inventors: Donald B. Grosser (Apex, NC); Vanitha Neelamegam (Chennai, IN); Maruthamuthu Palani (Chennai, IN); Balasubramanian Ramu (Chennai, IN); Kannan Selvaraj (Chennai, IN)

Assignee: Extreme Networks, Inc.

H04L45/16H04L12/18H04L12/1886H04L12/4641H04L12/6418

Abstract

Claims (51)

1. In a switching device, a method comprising:

receiving a request to program a multicast entry in a forwarding table for forwarding a data packet to multiple destinations, the forwarding table including a layer 2 table and a layer 3 table, the request associated with a layer 3 multicast group address;

identifying a protocol with which the request is associated, the protocol identified from among a plurality of protocols supported in the switching device;

determining a cache mode of the identified protocol to determine whether the identified protocol is associated with the layer 2 table or the layer 3 table;

in response to determining that the identified protocol is associated with the layer 2 table, converting the layer 3 multicast group address associated with the request into a layer 2 multicast group address;

programming the multicast entry for the layer 2 multicast group address associated with the request into the layer 2 table;

receiving a layer 3 multicast packet comprising a layer 3 address and a layer 2 address;

determining that the layer 3 address is not indicated in the layer 3 table;

in response to determining that the layer 3 address is not indicated in the layer 3 table, determining whether the layer 2 address of the layer 3 multicast packet is indicated by the multicast entry for the layer 2 multicast group address in the layer 2 table; and

in response to determining that the layer 2 address of the layer 3 multicast packet is indicated by the multicast entry for the layer 2 multicast group address in the layer 2 table, forwarding the layer 3 multicast packet based on the layer 2 multicast group address.

2. The method of claim 1 , further comprising:

determining whether the identified protocol with which the request is associated requires forwarding across VLANs based on mapping the identified protocol to a corresponding one of the layer 2 and layer 3 tables.

3. The method of claim 2 , wherein the mapping is encoded in a cache distribution table that maps each of the plurality of protocols supported in the switching device to the corresponding one of the layer 2 and layer 3 tables.

4. The method of claim 1 , wherein programming the multicast entry into the layer 3 table includes:

allocating a layer 3 index for insertion into the layer 3 table, the layer 3 index corresponding to the multicast group address; and

programming table entries corresponding to the allocated layer 3 index for an egress VLAN and port lists associated with the request.

5. The method of claim 1 , wherein programming the multicast entry into the layer 2 table includes:

converting the multicast group address associated with the request into a layer 2 multicast group address, the converted layer 2 multicast group address composed of a multicast group MAC address and egress VLAN associated with the request;

allocating a layer 2 index for insertion into the layer 2 table, the layer 2 index corresponding to the converted layer 2 multicast group address; and

programming egress table entries corresponding to the allocated layer 2 index for ports in port lists associated with the request.

6. The method of claim 5 , wherein programming the multicast entry into the layer 2 table further includes linking the multicast group address associated with the request with the converted layer 2 multicast group address.

7. The method of claim 1 , wherein the identified protocol requires forwarding across VLANs when the identified protocol is any one of a Protocol Independent Multicast (PIM), Multicast VLAN Registration (MVR) and Private VLAN protocols.

8. The method of claim 1 , wherein the identified protocol does not require forwarding across VLANs when the identified protocol is a snooping protocol, the snooping protocol including any one of an Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) snooping protocol.

9. The method of claim 1 , wherein the multicast entry is programmed into the layer 2 table as a static entry.

10. The method of claim 1 , further comprising searching for a Virtual Local Area Network Identifier (VLAN ID) associated with the request in the layer 2 table.

11. An article of manufacture comprising:

a non-transitory computer-readable medium including instructions that, when executed on a computer processor, cause the processor to:

receive a request to program a multicast entry in a forwarding table for forwarding a data packet to multiple destinations, the forwarding table including a layer 2 table and a layer 3 table, the request associated with a multicast group address;

identify a protocol with which the request is associated, the protocol identified from among a plurality of protocols supported in a switching device;

determine a cache mode of the identified protocol to determine whether the identified protocol is associated with the layer 2 table or the layer 3 table;

in response to determining that the identified protocol is associated with the layer 2 table, convert the multicast group address associated with the request into a layer 2 multicast group address;

program the multicast entry for the layer 2 multicast group address associated with the request into the layer 2 table;

receive a layer 3 multicast packet comprising a layer 3 address and a layer 2 address;

determine that the layer 3 address is not indicated in the layer 3 table;

in response to determining that the layer 3 address is not indicated in the layer 3 table, determine whether the layer 2 address of the layer 3 multicast packet is indicated by the multicast entry for the layer 2 multicast group address in the layer 2 table; and

in response to determining that the layer 2 address of the layer 3 multicast packet is indicated by the multicast entry for the layer 2 multicast group address in the layer 2 table, forward the layer 3 multicast packet based on the layer 2 multicast group address.

12. The article of manufacture of claim 11 , wherein the instructions further cause the processor to:

determine whether the identified protocol with which the request is associated requires forwarding across VLANs based on mapping the identified protocol to a corresponding one of the layer 2 and layer 3 tables.

13. The article of manufacture of claim 12 , wherein the mapping is encoded in a cache distribution table that maps each of the plurality of protocols supported in the switching device to the corresponding one of the layer 2 and layer 3 tables.

14. The article of manufacture of claim 11 , wherein the instructions causing the processor to program the multicast entry into the layer 3 table include instructions to:

allocate a layer 3 index for insertion into the layer 3 table, the layer 3 index corresponding to the multicast group address; and

program table entries corresponding to the allocated layer 3 index for an egress VLAN and port lists associated with the request.

15. The article of manufacture of claim 11 , wherein the instructions causing the processor to program the multicast entry into the layer 2 table include instructions to:

convert the multicast group address associated with the request into a layer 2 multicast group address, the layer 2 multicast group address composed of a multicast group MAC address and egress VLAN associated with the request;

allocate a layer 2 index for insertion into the layer 2 table, the layer 2 index corresponding to the converted layer 2 multicast group address; and

program egress table entries corresponding to the allocated layer 2 index for ports in port lists associated with the request.

16. The article of manufacture of claim 15 , wherein programming the multicast entry into the layer 2 table further includes linking the multicast group address associated with the request with the converted layer 2 multicast group address.

17. The article of manufacture of claim 11 , wherein the identified protocol requires forwarding across VLANs when the identified protocol is any one of a Protocol Independent Multicast (PIM), Multicast VLAN Registration (MVR) and Private VLAN protocols.

18. The article of manufacture of claim 11 , wherein the identified protocol does not require forwarding across VLANs when the identified protocol is a snooping protocol, the snooping protocol including any one of an Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) snooping protocol.

19. The article of manufacture of claim 11 , wherein the multicast entry is programmed into the layer 2 table as a static entry.

20. The article of manufacture of claim 11 , wherein the instructions further cause the processor to search for a Virtual Local Area Network Identifier (VLAN ID) associated with the request in the layer 2 table.

Assignments (9)

Continuity (2)