Packet Processing Pipeline PHV Expansion Without Extra Wiring
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Solution Overview
Problem
Existing configurable hardware switches face challenges in managing larger packet sizes and complex operations due to the limitations of expanding the packet header vector, which increases the number of wires and physical design area.
Innovation Solution
A network forwarding IC with a packet processing pipeline that utilizes multiple types of data containers, each with different availability and generation methods, allowing for the expansion of packet header vectors without increasing the number of wires or physical design area by using a parser, match-action stages, and a deparser to manage packet data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the packet header vector is enlarged to store more metadata and instructions, then the storage capacity is improved, but the number of wires and physical design area increases
Solution Approach 1:
The packet header vector is divided into multiple stages, with each stage processing a portion of the metadata. This segmentation allows the system to handle large amounts of data without requiring a single large storage structure, thereby reducing the physical design area while maintaining storage capacity.
Solution Approach 2:
The patent introduces a temporal dimension by processing packet header data through multiple sequential stages rather than storing all metadata simultaneously in a single vector. This transforms the problem from a spatial storage challenge to a temporal processing solution, reducing the physical area required.
2Adaptability or versatility
If the packet header vector is enlarged to accommodate larger packet sizes, then the packet size handling capability is improved, but the number of wires increases
Solution Approach 1:
The system dynamically allocates and processes packet header fields across multiple stages based on the actual packet size and requirements. This dynamic approach allows the system to adapt to varying packet sizes without provisioning for the maximum possible size in all components, reducing the number of wires required.
Solution Approach 2:
Each processing stage is designed to be universal and multi-functional, capable of handling different types of packet header fields and metadata. This universality allows the same hardware structure to accommodate various packet sizes without requiring additional dedicated wires for each specific case.
Data Source
AI summary
Some embodiments provide a network forwarding IC with packet processing pipelines, at least one of which includes a parser, a set of match-action stages, and a deparser. The parser is configured to receive a packet and generate a PHV including a first number of data containers storing data for the packet. A first match-action stage is configured to receive the PHV from the parser and expand the PHV to a second, larger number of data containers storing data for the packet. Each of a set of intermediate match-action stage is configured to receive the expanded PHV from a previous stage and provide the expanded PHV to a subsequent stage. A final match-action stage is configured to receive the expanded PHV and reduce the PHV to the first number of data containers. The deparser is configured to receive the reduced PHV from the final match-action stage and reconstruct the packet.