MULTICAST MISS NOTIFICATION FOR A DISTRIBUTED NETWORK SWITCH

• US 20130188640A1
• Filed: 02/25/2013
• Published: 07/25/2013
• Est. Priority Date: 01/19/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cors, Josep, Greenfield, Todd A., Shedivy, David A., Walk, Bruce M.
• Granted Patent: US 9,197,539 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 45/16 Multipoint routing

Abstract

Techniques are provided for multicast miss notification for a distributed network switch. In one embodiment, a bridge element in the distributed network switch receives a frame destined for a multicast group on a network. If a local multicast forwarding table of the bridge element does not include any forwarding entry for the multicast group, a forwarding entry is selected from the local multicast forwarding table as a candidate for being replaced. An indication of the candidate is sent to a management controller in the distributed network switch.

Claims

1. A computer-implemented method for multicast miss notification in a distributed network switch that includes a first switch module, the method comprising

receiving, by a bridge element of the first switch module, a frame destined for a multicast group on a network, wherein the first switch module includes a management controller associated with a global multicast forwarding table that includes a plurality of forwarding entries, wherein the bridge element is associated with a local multicast forwarding table specific to the bridge element and that includes a subset of the plurality of forwarding entries;

determining that the local multicast forwarding table associated with the bridge element does not include a forwarding entry for the multicast group for which the frame is addressed;

selecting a first forwarding entry from the local multicast forwarding table as a candidate for replacing with a forwarding entry for the multicast group for which the frame is destined; and

sending, to the management controller, an indication that the first forwarding entry is the candidate for replacing with the forwarding entry for the multicast group for which the frame is destined.

2. The computer-implemented method of claim 1, wherein the management controller is configured to:

retrieve, from the global multicast forwarding table, the forwarding entry for the multicast group, and wherein the management controller; and

store the retrieved forwarding entry in the local multicast forwarding table, based on the indication.

3. The computer-implemented method of claim 1, wherein the predefined selection criteria comprises a time that the forwarding entry was last accessed in processing a multicast frame.

4. The computer-implemented method of claim 1, wherein the bridge element comprises a distributed virtual Ethernet bridge (dVEB), and wherein the indication serves as a hint to the management controller which multicast forwarding entry is to replace.

5. The computer-implemented method of claim 1, wherein the indication comprises an index of the first forwarding entry in the local multicast forwarding table, and wherein the forwarding entry for the multicast group for which the frame is destined comprises at least one of a logical network of the multicast group, a virtual local area network (VLAN) of the multicast group, and a Media Access Control (MAC) address for the multicast group.

6. The computer-implemented method of claim 1, further comprising:

prior to sending the indication to the management controller, sending the frame to a broadcast domain associated with the network.

7. The computer-implemented method of claim 1, wherein the bridge element is configured to, upon determining that the local multicast forwarding table associated with the bridge element includes a forwarding entry for a second multicast group for which a second frame is destined, sending the second frame to the second multicast group based on the forwarding entry.