Packet-Action Cache Fingerprints for Low-Power Packet Classification
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Solution Overview
Problem
Network devices face challenges in efficiently classifying ingress packets due to the large size of packet headers, leading to either large, expensive, and power-consuming cache memories or small cache capacities, which can result in false-positive fingerprint identification and potential blocking of packet flows.
Innovation Solution
The implementation of a Packet-Action Cache Memory (PACM) that uses smaller fingerprints derived from packet headers, allowing for reduced cache size and power consumption, with mechanisms to mitigate false positives through periodic flushing and a stash memory to resolve ambiguities, ensuring low false-positive probabilities and maintaining efficient packet processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cache memory size is increased to store full packet headers for accurate classification, then packet classification accuracy is improved, but device cost and power consumption increase
Solution Approach 1:
The patent extracts only the essential identifying features from packet headers to create compact fingerprints. Instead of storing and comparing complete packet headers, the system calculates hash-based fingerprints that capture the essential classification information in a condensed form, significantly reducing memory requirements and power consumption while maintaining classification accuracy.
Solution Approach 2:
The patent transforms packet headers into a different parameter representation through hash function calculation. The original large-scale parameter (full packet header) is converted into a compact fingerprint parameter that preserves classification capability while occupying minimal storage space and requiring minimal processing energy.
2Use of energy by stationary object
If cache memory size is reduced to decrease cost and power consumption, then device cost and power usage are reduced, but false-positive identification increases
Solution Approach 1:
The patent performs preliminary hash calculation on packet headers before cache lookup to generate unique fingerprints. This preliminary transformation ensures that even with reduced cache size, the probability of different packets producing the same fingerprint (false positive) remains extremely low, thereby maintaining reliability while using smaller memory.
Solution Approach 2:
The patent creates a simplified copy of packet header information in the form of a fingerprint. This fingerprint copy contains sufficient information for accurate classification without requiring the full original header data, enabling smaller cache memory while preserving classification reliability.
3Quantity of substance
If smaller fingerprints are used to reduce cache size, then memory capacity and power consumption are reduced, but false-positive probability increases
Solution Approach 1:
The patent replaces the mechanical approach of storing and comparing full packet headers with a mathematical hash function-based fingerprinting system. This substitution enables the use of much smaller fingerprint values while maintaining extremely low false-positive probabilities through the properties of cryptographic hash functions.
Solution Approach 2:
The patent changes the parameter representation from full packet headers to compact hash-based fingerprints. This parameter transformation achieves dramatic reduction in memory size (from thousands of bytes to dozens of bytes) while the mathematical properties of the hash function ensure that false-positive probability remains negligibly small.
Data Source
AI summary
A network device includes at least one communication ingress port, ingress packet processing circuitry and a packet-action cache memory (PACM). The at least one communication ingress port is configured to receive packets including packet headers from a network. The ingress packet processing circuitry is configured to receive the packets and to process the packets in accordance with respective packet actions specified for the packets. The PACM is configured to store one or more of the packet actions in association with one or more respective fingerprints which are calculated over the packet headers of the corresponding packets, for use by the ingress packet processing circuitry. The fingerprints are smaller than the corresponding packet headers.