Computer-based flow synchronization for efficient multicast forwarding for products and services

Patent metadata

Field	Value
Publication number	US-9722810-B2
Application number	US-201414171015-A
Country	US
Kind code	B2
Filing date	Feb 3, 2014
Priority date	Feb 3, 2014
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A method for synchronizing multicast message subflows in a switched network includes associating, with a processing device, a first destination identifier corresponding to a multicast message with a first queue that corresponds to a first output port of a switching device, associating, with a processing device, a second destination identifier corresponding to the multicast message with a second queue that corresponds to a second output port of the switching device, pausing the first queue in response to a message counter corresponding to the first queue crossing a first predetermined threshold, and unpausing the first queue in response to the message counter crossing a second predetermined threshold, wherein the message counter indicates a quantity of data that has been forwarded by the first queue but remains to be forwarded by the second queue.

First claim

What is claimed is:

1. A method for synchronizing multicast message subflows in a switched network, comprising:
storing, to a payload replication buffer, a payload packet corresponding to a multicast message internal to a switching fabric of a switching device, wherein a pointer to a memory location of the payload packet is stored in a multicast header associated with the multicast message;
associating, with a processing device, a first destination identifier corresponding to the multicast message with a first queue that corresponds to a first output port of the switching device;
associating, with a processing device, a second destination identifier corresponding to the multicast message with a second queue that corresponds to a second output port of the switching device; and
facilitating flow synchronization for the first queue and the second queue to prevent an overload of the payload replication buffer, wherein the flow synchronization comprises
incrementing a subflow counter and a message counter when the first queue forwards a message to a destination;
decrementing the subflow counter when the first queue and the second queue have each forwarded at least one message;
pausing transmission of the multicast message by the first queue in response to the subflow counter crossing a first predetermined threshold, wherein the transmission of the multicast message by the first queue is paused when the second queue is determined to be behind by the first queue in message transmissions by a predetermined threshold based on the subflow counter; and

unpausing the first queue in response to the subflow counter crossing a second predetermined threshold, wherein the subflow counter crossing the second predetermined threshold is indicative that the second queue is within a predetermined range of the first queue for messages transmitted, wherein transmission of the multicast message by the first queue comprises forwarding the multicast header associated with the multicast message to the switching fabric that will use the pointer in the multicast header to forward a stored payload in the payload replication buffer to the first destination identifier.

2. The method of claim 1 , further comprising:
incrementing the message counter in response to the first queue forwarding the destination identifier;
adjusting the subflow counter corresponding to the multicast message in response to the first queue forwarding the destination identifier, wherein the subflow counter indicates a number of queues associated with the multicast message; and
decrementing the message counter in response to the subflow counter indicating that all queues associated with the multicast message have forwarded the destination identifier.

3. The method of claim 2 , further comprising:
initializing the message counter to zero; and
initializing the subflow counter to an initial number of queues with which the destination identifier is associated, wherein adjusting the subflow counter includes decrementing the subflow counter, and the subflow counter indicates a current number of queues associated with the multicast message that remain to forward the destination identifier.

4. The method of claim 1 , further comprising:
receiving at least a portion of the multicast message at an input port associated with the switching device; and
storing payload data corresponding to the multicast message in a replication buffer associated with the switching fabric of the switching device.

5. The method of claim 4 , wherein the first queue and the second queue further correspond to the input port.

6. The method of claim 4 , further comprising:
forwarding the destination identifier to the switching fabric;
replicating at least a portion of the payload data corresponding to the multicast message from the replication buffer; and
sending the replicated payload data via the output port.

7. The method of claim 4 , wherein the first predetermined threshold is greater than a total size of the replication buffer.

8. The method of claim 1 , wherein the first queue is associated with a plurality of destination identifiers corresponding to a plurality of network messages.

9. The method of claim 8 , wherein the first queue forwards destination identifiers on a first-in-first-out basis using a request-grant protocol.

10. A system for synchronizing multicast message subflows in a switched network, comprising:
a switching device configured to
store, to a payload replication buffer, a payload packet corresponding to a multicast message internal to a switching fabric of the switching device, wherein a pointer to a memory location of the payload packet is stored in a multicast header associated with the multicast message,
associate a first destination identifier corresponding to the multicast message with a first queue that corresponds to a first output port of the switching device, and
associate a second destination identifier corresponding to the multicast message with a second queue that corresponds to a second output port of the switching device;

a subflow controller configured to facilitate flow synchronization for the first queue and the second queue to prevent an overload of a payload replication buffer, wherein the flow synchronization comprises
incrementing a subflow count and a message count when the first queue forwards a message to a destination;
decrementing the subflow count when the first queue and the second queue have each forwarded at least one message;
pausing transmission of the multicast message by the first queue in response to the subflow count crossing a first predetermined threshold, wherein the transmission of the multicast message by the first queue is paused when the second queue is determined to be behind by the first queue in message transmissions by a predetermined threshold based on the subflow count, and
unpausing transmission of the multicast message by the first queue in response to the subflow count crossing a second predetermined threshold, wherein the subflow count crossing the second predetermined threshold is indicative that the second queue is within a predetermined range of the first queue for messages transmitted wherein transmission of the multicast message by the first queue comprises forwarding the multicast header associated with the multicast message to the switching fabric that will use the pointer in the multicast header to forward the stored payload in the payload replication buffer to the first destination identifier.

11. The system of claim 10 , further comprising:
a message counter configured to increment the message count in response to the first queue forwarding the destination identifier, wherein the message count is a number-ahead variable; and
a subflow counter configured to adjust the subflow count corresponding to the multicast message in response to the first queue forwarding the destination identifier, wherein the reference count indicates a number of queues associated with the multicast message, and the message counter is further configured to decrement the message count in response to the subflow counter indicating that all queues associated with the multicast message have forwarded the destination identifier.

12. The system of claim 11 , wherein the message counter is further configured to initialize the message count to zero, the subflow counter is further configured to initialize the subflow count to an initial number of queues with which the destination identifier is associated, adjusting the subflow counter includes decrementing the subflow count, and the subflow count indicates a current number of queues associated with the multicast message that remain to f

Assignees

• IBM

Inventors

• Basso Claude
• Chrysos Nikolaos
• Minkenberg Cyriel
• Shedivy David A
• Valk Kenneth M
• Vanderpool Brian T

Classifications

• H04L12/1881 Primary

  with schedule organisation, e.g. priority, sequence management · CPC title

• H04L47/29

  using a combination of thresholds · CPC title

• H04L47/32

  by discarding or delaying data units, e.g. packets or frames · CPC title