Tri-color Packet Counting Using Dual TCAM Segmentation
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Solution Overview
Problem
Existing solutions using generic TCAMs can only count two colors of packets in a tri-color marking scheme due to cost and speed constraints, limiting the ability to fully account for flow characteristics in debugging or accounting purposes.
Innovation Solution
Implementing a method that utilizes two TCAMs with three counters each, where one TCAM counts green and yellow packets separately and the second TCAM counts all packets, allowing the count of red packets to be derived by subtracting the sum of green and yellow counts from the total.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single TCAM is used to count packets, then cost and device complexity are reduced, but the ability to count all three colors of packets is lost
Solution Approach 1:
The patent divides the packet counting function across two separate TCAMs: first TCAM counts green and yellow packets, second TCAM counts all packets. This segmentation enables full tri-color counting capability while managing device complexity through functional division.
Solution Approach 2:
Each TCAM entry is configured with multiple counters that can serve different counting purposes. The first TCAM entry has counters for both green and yellow packets, while the second TCAM entry has a counter for all packets, making each TCAM multi-functional in supporting the overall tri-color counting objective.
2Loss of information
If two TCAMs with three counters each are used to count all packet colors, then complete packet statistics are achieved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the counting of specific packet colors (green and yellow) from the general counting function by dedicating specific counters in the first TCAM to these colors, while the second TCAM handles total packet counting. This extraction approach ensures complete statistics are captured without requiring all three counters to be implemented in every TCAM.
Solution Approach 2:
The system uses an intermediary calculation approach where red packet counts are derived by subtracting the sum of green and yellow counts from the total packet count. This intermediary mathematical operation enables complete tri-color statistics without requiring a third dedicated TCAM for red packet counting.
3Quantity of substance
If counters are configured for all three packet colors in each TCAM entry, then complete counting capability is achieved, but resource utilization becomes inefficient
Solution Approach 1:
Instead of configuring all three counters in every TCAM entry, the patent applies partial action by configuring only the necessary counters in each TCAM: the first TCAM has counters for green and yellow packets, while the second TCAM has a counter for total packets. This partial configuration achieves complete counting capability while avoiding wasted TCAM resources.
Data Source
AI summary
The invention is directed to counting data packets marked according to tri-color marking techniques. Packets of a packet flow that are marked according to a three color (or tri-color) marking scheme are counted using a counter implemented on a ternary content addressable memory (TCAM). Advantages of some embodiments of the invention are to enable the use of generic and cost-efficient TCAMs to quickly obtain the counts of all three colors of packets in such a packet flow. These counts can be used to provide detailed statistics on characteristics of the packet flow, which can be useful for debugging and accounting purposes.