Multicast Flow Reordering via Status Markers

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Solution Overview

Problem

Dynamic load balancing in multicast data transmission within communication networks often results in multicast data packets arriving out of order at the egress node, particularly when flows are reassigned from one sublink to another, leading to ordering issues due to the lack of sequence numbers in un-arbitrated multicast traffic.

Innovation Solution

A system and method for multicast data traffic flow reordering that marks data packets with 'last,' 'new,' or 'in-order' status indicators, allowing the egress node to reorder packets based on these markings and manage a reorder queue to ensure correct ordering, even in the absence of sequence numbers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If dynamic load balancing is used to reassign multicast flows to new paths, then network resource utilization is improved, but packet ordering is deteriorated

Engineering Contradiction:
Improvenetwork resource utilizationVSAvoidpacket ordering
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The ingress node performs preliminary actions by marking packets with status indicators ('last', 'new', 'in-order') before packets are transmitted through different paths. This pre-marking enables the egress node to correctly reorder packets without requiring sequence numbers, thus maintaining packet ordering reliability while allowing dynamic load balancing to improve network resource utilization

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Status indicator markings serve as an intermediary mechanism between the load balancing function and the packet delivery function. These markings carry ordering information through the network without adding complex sequence numbers, enabling the egress node to reconstruct proper packet order despite packets traversing different paths due to dynamic load balancing

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If sequence numbers are added to multicast packets for reordering, then packet ordering is improved, but protocol overhead is increased

Engineering Contradiction:
Improvepacket orderingVSAvoidprotocol overhead
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using complex, persistent sequence numbers that require significant processing and storage resources, the invention uses simple status indicator markings that are lightweight and disposable. These markings are added to packets at the ingress node and processed at the egress node, providing packet ordering functionality with minimal overhead and without requiring complex state maintenance

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the parameter used for packet identification from traditional sequence numbers to status indicator markings. This parameter change reduces the complexity and overhead of packet ordering while maintaining the ability to correctly reorder packets at the egress node, as the status indicators provide sufficient information for reordering without the burden of full sequence number processing

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3008868B1Multicast flow reordering scheme
Publication Date: 2019.02.13 CISCO TECHNOLOGY INC
  • EP3008868B1 patent drawingFigure 1~2A
  • EP3008868B1 patent drawingFigure 2B
  • EP3008868B1 patent drawingFigure 3

AI summary

An example system and method for multicast flow reordering in a network is provided and includes receiving a data packet at an egress of a node, the data packet associated with a descriptor including at least one parameter; determining the at least one parameter of the descriptor; and processing the data packet for reordering based on the determining of the at least on parameter of the descriptor.