TCAM Entry Purging via Age Tracking for Network Routing
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Solution Overview
Problem
Current network devices face challenges in efficiently managing and routing frames across multiple protocols and rates, particularly in handling the aging of ternary content addressable memory (TCAM) entries, which affects their performance and efficiency in handling diverse network and storage protocols.
Innovation Solution
The implementation of a network device with a TCAM module that stores routing entries for multiple sub-ports, each with an associated history value to purge old entries based on age, and a scheduler to manage requests across various network links and protocols, ensuring efficient frame routing and handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TCAM entries are retained for longer periods to maintain routing information, then routing reliability is improved, but TCAM memory capacity is consumed and new entries cannot be accommodated
Solution Approach 1:
The patent changes the state of TCAM entries by introducing age bits that track the temporal state of each entry. This parameter change enables the system to differentiate between new and old entries, allowing selective retention or purging based on age criteria while maintaining routing reliability for active entries and freeing TCAM capacity for new entries.
2Quantity of substance
If TCAM entries are purged based on age to accommodate new entries, then TCAM memory availability is improved, but routing reliability may deteriorate due to loss of valid routing information
Solution Approach 1:
The patent implements a feedback mechanism where age bits continuously track the lifetime of TCAM entries. This feedback information is used by the purging logic to make informed decisions about which entries to remove, ensuring that only genuinely obsolete entries are purged while maintaining routing reliability for active entries that still require the TCAM space.
3Adaptability or versatility
If the network device handles multiple protocols and rates across numerous sub-ports, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal TCAM entry structure with standardized age bits and purging logic that works across multiple protocols (Ethernet, Fibre Channel, InfiniBand) and rate configurations. This multi-functional approach allows the same hardware mechanism to handle diverse protocols and sub-ports without requiring protocol-specific purging logic, thereby managing complexity while maintaining high adaptability.
Data Source
AI summary
Methods and systems for a network device having a plurality of base-ports, each base-port having a plurality of sub-ports configured to operate independently as a port for sending and receiving information using one of a plurality of network links at a plurality of rates complying with a plurality of protocols. The network device includes a ternary content addressable memory (TCAM) module for storing a plurality of entries for routing frames that are received for the plurality of sub-ports complying with the plurality of protocols. Each TCAM entry has an associated history value that is used by a processor for the network device to purge TCAM entries based on an age of the TCAM entries.