Order-Sensitive Packet Marking in LLN Routing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Low Power and Lossy Networks (LLNs) face challenges such as lossy links, low bandwidth, and packet reordering, which affect communication reliability, especially in Smart Grid and Smart Cities applications, where traditional protocols like SCADA do not tolerate out-of-order packets, leading to communication failures.
Innovation Solution
The method involves marking packets sensitive to reordering, maintaining state about routing paths, and buffering out-of-order packets to restore original order, with devices signaling to adjust rerouting strategies to minimize future reordering, using techniques integrated into existing protocols like RPL and SCADA protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If packets are routed through multiple paths in LLNs to improve network utilization and reliability, then network robustness and bandwidth utilization are improved, but packet reordering occurs which causes communication failures in order-sensitive protocols
Solution Approach 1:
The patent applies preliminary action by marking packets as order-sensitive before routing, so that receiving devices can proactively buffer and reorder packets before protocol processing occurs. This prevents communication failures by ensuring proper packet ordering is established in advance, rather than reacting after reordering causes protocol errors.
Solution Approach 2:
The patent introduces an intermediary mechanism (packet marking and buffering system) between the routing layer and the application layer. The marking system acts as a mediator that identifies order-sensitive packets and routes them through buffering mechanisms, separating the routing function from the ordering requirement and allowing multiple paths while maintaining protocol compatibility.
2Reliability
If packets are buffered and reordered at receiving devices to fix out-of-order delivery, then communication reliability for order-sensitive protocols is improved, but network latency and device complexity increase
Solution Approach 1:
The patent applies local quality by implementing buffering and reordering only for packets marked as order-sensitive, rather than buffering all packets universally. This selective approach maintains reliability for protocols that require it (like SCADA) while allowing uninterrupted flow for protocols that tolerate reordering, thus minimizing overall network latency.
Solution Approach 2:
The patent uses partial action by applying reordering mechanisms only to the extent necessary - specifically for order-sensitive packets identified through marking. Instead of implementing comprehensive reordering for all traffic, the system applies the buffering mechanism selectively, reducing unnecessary latency for time-sensitive applications that don't require strict ordering.
3Adaptability or versatility
If routing protocols like RPL are used in LLNs to manage packet routing, then network management capability is improved, but packet reordering occurs due to dynamic path selection which harms order-sensitive applications
Solution Approach 1:
The patent applies segmentation by dividing packet handling into two distinct categories: order-sensitive packets (marked and buffered) and order-tolerant packets (routed normally). This segmentation allows the routing protocol to maintain its dynamic path selection capabilities for overall network management while isolating order-sensitive traffic into a separate handling stream that prevents reordering issues.
Solution Approach 2:
The patent introduces packet marking as an intermediary layer between the routing protocol and packet forwarding. This marking mechanism acts as a mediator that preserves the adaptability of dynamic routing protocols like RPL while filtering out order-sensitive packets for special handling, thus decoupling the routing flexibility from the ordering requirement.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In one embodiment, a device in a network determines that a particular packet flow in the network is sensitive to packet reordering. The device determines whether a particular packet of the packet flow is to be routed differently than an immediately prior packet in the packet flow, in response to determining that the particular packet flow is sensitive to reordering. The device marks the particular packet as taking a different route than the immediately prior packet in the packet flow, prior to forwarding the marked packet and in response to determining that the particular packet is to be routed differently than the immediately prior packet in the packet flow.