Back-pressure Control in Telecommunications Transport Networks
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Solution Overview
Problem
Next-generation telecommunications networks, such as 5G, face inadequate congestion control mechanisms, particularly in the midhaul transport network, due to varying link speeds and resource imbalances, leading to buffer overflow and packet loss.
Innovation Solution
A system for back-pressure control in the transport network, where a first network node monitors buffer states, dynamically adjusts sampling rates, and sends congestion notification messages to adjust parameters at second network nodes based on back-off information, reducing PDCP transmissions and improving network efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TCP's built-in rate adaptive mechanism is used to respond to network congestion, then packet loss is reduced through re-transmission, but network efficiency deteriorates due to increased latency and reduced throughput
Solution Approach 1:
The patent implements preliminary congestion notification by sending back-pressure messages from egress nodes to ingress nodes before buffer overflow occurs. This early warning system allows the ingress node to proactively reduce transmission rate, preventing packet loss without requiring actual packet drops and re-transmissions, thus maintaining both reliability and throughput
Solution Approach 2:
The patent establishes a feedback mechanism where egress nodes monitor buffer occupancy and send congestion notifications back to ingress nodes. This closed-loop feedback enables dynamic adjustment of transmission rates based on real-time network conditions, allowing TCP to respond to congestion signals without waiting for packet loss, thereby improving both reliability and network efficiency
2Reliability
If buffer size is increased to absorb congestion variation, then packet loss is reduced, but device complexity and memory requirements increase
Solution Approach 1:
The patent introduces congestion notification messages as an intermediary mechanism between ingress and egress nodes. Instead of relying solely on large buffers to absorb congestion, the system uses these notification messages to coordinate traffic flow, allowing smaller buffers to achieve the same congestion absorption effect, thereby reducing device complexity and memory requirements while maintaining reliability
3Reliability
If congestion notification messages are sent frequently to compensate for congestion, then network reliability is improved, but loss of time increases due to additional signaling overhead
Solution Approach 1:
The patent implements periodic sampling of buffer occupancy at the egress node, where congestion notifications are sent at regular intervals rather than continuously. This periodic action reduces signaling overhead and time loss while maintaining effective congestion compensation, as the buffered traffic between sampling points is already accounted for in the buffer management mechanism
Data Source
AI summary
Back-pressure control in a telecommunications network, in which a method of back-pressure control in a transport network is provided. A buffer state of a buffer is monitored. A condition indicative of back-pressure is also determined in response to a change of the buffer state passing a predetermined limit. In response to determining the condition indicative of back-pressure, a back-pressure notification message is created and, subsequently, transmitted to at least one second network node.