CREDIT-BASED FLOW CONTROL FOR MULTICAST PACKETS IN LOSSLESS ETHERNET NETWORKS

• US 20160173400A1
• Filed: 02/23/2016
• Published: 06/16/2016
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Kyndryl Incorporated (Kyndryl Holdings, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Banavalikar, Bhalachandra G., DeCusatis, Casimer M., Gusat, Mircea, Kamble, Keshav G.
• Granted Patent: US 9,699,105 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/34 Source routing
• CPC Class Codes: H04L 47/39 Credit based

Abstract

Methods and systems presented herein provide for self-routing multicast. In one embodiment, a method includes receiving, using a switch controller, a multicast data stream join request from a source in a network, and creating, using the switch controller, a multipath identifier (ID) for a multicast data stream. Moreover, the method includes creating, using the switch controller, path identifiers (IDs) for intermediate switches in the network based on a local network topology database. Each path ID is associated with an output port bitmap. The method also includes transmitting, using the switch controller, the multipath ID and a path ID to a source of the multicast data stream, the path ID corresponding to the source of the multicast join request. Also, the multipath ID and the path ID are configured to allow the source of the multicast data stream to determine an output port mapping for a packet.

Claims

1. A system, comprising:

a switch controller comprising a hardware processor and logic integrated with and/or executable by the processor, the logic being configured to;

receive a multicast data stream join request from a source in a network;

create a multipath identifier (ID) for a multicast data stream;

create a series of path identifiers (IDs) for intermediate switches in the network based on a local network topology database, each path ID being associated with an output port bitmap; and

transmit the multipath ID and a path ID to a source of the multicast data stream, the path ID corresponding to the source of the multicast join request; and

the source of the multicast data stream configured to;

receive the multipath ID and path ID from the switch controller;

create a unicast packet having the multipath ID in a header of the unicast packet, wherein the header comprises a multicast group address appended to an end of the multipath ID; and

determine at least one output port with which to forward the unicast packet, the output port corresponding to the source of the multicast join request; and

a recipient of the unicast packet configured to convert the unicast packet into a multicast packet using the multicast group address before sending the multicast packet to a device which is not capable of interpreting the multipath ID in the header of the unicast packet.

2. The system as recited in claim 1, wherein the multicast join request is an internet group management protocol (IGMP) join request, and wherein IGMP snooping is enabled on the source of the multicast join request.

3. The system as recited in claim 1, wherein the source of the multicast data stream and the source of the multicast join request are explicit multicast (Xcast)-compliant.

4. The system as recited in claim 1, wherein the logic is configured to collect and store maximum transmission units (MTUs) for inter-switch links (ISLs) positioned between the intermediate switches in the network.

5. The system as recited in claim 1, wherein the source of the multicast data stream is a virtual or physical switch, and wherein the at least one output port is determined based on the multipath ID and the path ID which corresponds to an output port mapping.

6. The system as recited in claim 5, wherein the virtual or physical switch comprises logic configured to:

duplicate the unicast packet based on the output port mapping indicating that multiple output ports are used to forward the unicast packet; and

forward the one or more unicast packets according to the output port mapping.

7. The system as recited in claim 1, wherein the source of the multicast data stream is a server, the server comprising logic configured to send the unicast packet to a first switch in the multipath as indicated by the output port mapping.

8. The system as recited in claim 1, wherein broadcast and/or multicast routing tables are not used by the intermediate switches in the network due to implementation of the path IDs specific to each intermediate switch to create a broadcast group.

9. A method comprising:

receiving, using a switch controller, a multicast data stream join request from a source in a network;

creating, using the switch controller, a multipath identifier (ID) for a multicast data stream;

creating, using the switch controller, a series of path identifiers (IDs) for intermediate switches in the network based on a local network topology database, each path ID being associated with an output port bitmap;

transmitting, using the switch controller, the multipath ID and a path ID to a source of the multicast data stream, the path ID corresponding to the source of the multicast join request;

receiving, using the source of the multicast data stream, the multipath ID and path ID from the switch controller;

creating, using the source of the multicast data stream, a unicast packet having the multipath ID in a header of the unicast packet, wherein the header comprises a multicast group address appended to an end of the multipath ID;

determining, using the source of the multicast data stream, at least one output port with which to forward the unicast packet, the output port corresponding to the source of the multicast join request; and

converting, using a recipient of the unicast packet, the unicast packet into a multicast packet using the multicast group address before sending the multicast packet to any device which is not capable of interpreting the multipath ID in the header of the unicast packet.

10. The method as recited in claim 9, wherein the source of the multicast data stream is a virtual or physical switch, and wherein the at least one output port is determined based on the multipath ID and the path ID which corresponds to an output port mapping, and further comprising:

duplicating, using the virtual or physical switch, the unicast packet using the switch when the output port mapping indicates that multiple output ports are used to forward the unicast packet; and

forwarding, using the virtual or physical switch, the one or more unicast packets according to the output port mapping.

11. The method as recited in claim 9, wherein the multicast join request is an internet group management protocol (IGMP) join request, and wherein IGMP snooping is enabled on the source of the multicast join request.

12. The method as recited in claim 9, wherein the source of the multicast data stream and the source of the multicast join request are explicit multicast (Xcast)-compliant.

13. The method as recited in claim 9, further comprising collecting and storing, using the switch controller, maximum transmission units (MTUs) for any inter-switch links (ISLs) positioned between the intermediate switches in the network.

14. The method as recited in claim 9, wherein the source of the multicast data stream is a virtual or physical switch, and wherein the at least one output port is determined based on the multipath ID and the path ID which corresponds to an output port mapping.

15. The method as recited in claim 14, further comprising:

duplicating, using the virtual or physical switch, the unicast packet in response to a determination that the output port mapping indicates that multiple output ports are used to forward the unicast packet; and

forwarding, using the virtual or physical switch, the one or more unicast packets according to the output port mapping.

16. The method as recited in claim 9, wherein the source of the multicast data stream is a server, further comprising sending, using the server, the unicast packet to a first switch in the multipath as indicated by the output port mapping.

17. The method as recited in claim 9, wherein broadcast and/or multicast routing tables are not used by the intermediate switches in the network due to implementation of the path IDs specific to each intermediate switch to create a broadcast group.

18. A system, comprising:

a hardware processor and logic integrated with and/or executable by the processor, the logic being configured to;

receive a unicast packet having a multipath identifier (ID) and a multicast group address stored in a header of the unicast packet;

convert the unicast packet into a multicast packet using the multicast group address; and

send the multicast packet to a device identified in the multipath ID which is not capable of interpreting the multipath ID stored in the header of the unicast packet.

19. A method comprising:

receiving, using a switch controller, a multicast data stream join request from a source in a network;

creating, using the switch controller, a multipath identifier (ID) for a multicast data stream;

creating, using the switch controller, path identifiers (IDs) for intermediate switches in the network based on a local network topology database, each path ID being associated with an output port bitmap; and

transmitting, using the switch controller, the multipath ID and a path ID to a source of the multicast data stream, the path ID corresponding to the source of the multicast join request,

wherein the multipath ID and the path ID are configured to allow the source of the multicast data stream to determine an output port mapping for a packet.