Network Device Pacing Rate Adjustment for Congestion Avoidance
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Solution Overview
Problem
In data communications networks, packet transmission pacing is hindered by mismatched rates between incoming packets and egress link capabilities, leading to congestion and packet dropping, especially when network elements like Wi-Fi links or mobile devices buffer packets together, and existing protocols struggle to re-establish pacing rates and fairly discard packets in congested scenarios.
Innovation Solution
A method where network devices detect pacing rate information in packets, determine a desired pacing rate to reduce packet dropping, and transmit packets at this rate, with the ability to aggregate flows, estimate pacing rates for flows without explicit information, and preferentially discard packets from flows with higher desired pacing rates to manage congestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If packets are transmitted at high rates to improve network throughput, then productivity increases, but packet dropping increases due to congestion
Solution Approach 1:
The patent applies preliminary action by proactively pacing packets before they enter congested network links. Network devices detect pacing rates in incoming packets and adjust the transmission rate in advance to prevent buffer overflow and packet dropping, rather than reacting after congestion occurs. This is implemented through pacing rate detection mechanisms that examine packet metadata and adjust egress timing accordingly.
Solution Approach 2:
The patent implements feedback by using pacing rate information embedded in packet metadata to continuously adjust transmission rates. Network devices monitor the pacing rates of incoming flows, compare them against link capacity and current congestion state, and dynamically modify the egress pacing rate. This closed-loop feedback mechanism allows the system to maintain high throughput while adapting to changing network conditions to prevent packet loss.
2Reliability
If network devices buffer packets to manage rate mismatches, then packet loss decreases, but congestion increases and fairness among flows deteriorates
Solution Approach 1:
The patent applies segmentation by treating each network flow independently with its own detected pacing rate. Instead of aggregating all packets into a single buffer pool, the system maintains separate pacing state for each flow, allowing individualized rate adjustment. This enables fair congestion management where each flow is paced according to its own characteristics and the current network state, preventing any single flow from dominating the buffer resources.
Solution Approach 2:
The patent implements local quality by applying different pacing rates to different flows based on their individual characteristics and current network conditions. Each flow receives customized pacing treatment rather than uniform buffering, with network devices adjusting the egress rate for each flow independently based on detected pacing information and link availability. This localized approach ensures fair resource allocation while maintaining overall network efficiency.
3Measurement precision
If pacing rate information is explicitly included in packets, then transmission control precision improves, but device complexity and information overhead increase
Solution Approach 1:
The patent applies partial action by extracting only the essential pacing rate information from packet metadata rather than processing all packet fields. Network devices selectively examine specific portions of packet headers or associated control data to obtain pacing rate values, ignoring unnecessary information. This partial processing approach provides sufficient pacing control precision while minimizing the computational overhead and device complexity required for packet inspection and rate adjustment.
Data Source
AI summary
The subject technology discloses configurations for receiving, at a first network device, a set of network packets corresponding to a first flow from a client, wherein the set of network packets includes a destination address of a second network device; detecting, in the received set of network packets, pacing rate information indicating a specified pacing rate for transmission of the network packets; determining, based on the detected pacing rate, a desired pacing rate to reduce packet dropping on route to the second network device; and transmitting, by the first network device, the set of network packets over an egress link at the desired pacing rate.