IP Route Aggregation via Gap Filling for TCAM Optimization
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Solution Overview
Problem
The increasing size of Internet Protocol (IP) route tables necessitates more router memory and processing power, leading to challenges with TCAM space, power consumption, and potential un-deterministic IP forwarding behavior due to limited capacity.
Innovation Solution
Identifying gaps in subsets of route entries with the same next hop and filling them to make the subsets contiguous, allowing for aggregation into single route entries in the forwarding table, with additional entries having priority for proper forwarding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of IP routes in the route table is increased to support more prefixes, then the routing capability and coverage are improved, but the TCAM space requirement and power consumption increase significantly
Solution Approach 1:
The patent merges multiple route entries with the same next hop into a single aggregated route entry. By identifying gaps in route entry ranges and filling them with synthetic entries, the system creates contiguous blocks that can be aggregated, reducing the number of individual TCAM entries while maintaining the same routing functionality and next hop information.
Solution Approach 2:
The patent performs preliminary gap-filling by identifying missing route entries between existing routes with the same next hop. These synthetic gap entries are added before aggregation to enable contiguous grouping, allowing the system to prepare the route table structure in advance for efficient aggregation and reduced TCAM usage.
2Quantity of substance
If the number of TCAM chips is increased to accommodate more route entries, then the forwarding table capacity is improved, but the cost and power consumption increase
Solution Approach 1:
The patent combines multiple route entries into aggregated entries that represent contiguous ranges of prefixes. This merging reduces the total number of entries that need to be stored in TCAM, thereby reducing the number of TCAM chips required while maintaining the full forwarding table capacity through the aggregated representation.
3Quantity of substance
If route entries are aggregated to reduce forwarding table size, then memory usage is reduced, but the forwarding accuracy may be compromised if gaps are not properly handled
Solution Approach 1:
The patent performs preliminary gap identification and filling before aggregation. By synthesizing missing route entries in the gaps and adding them to the route table, the system ensures that the aggregated ranges are contiguous and complete, preventing any forwarding accuracy issues while still achieving memory reduction through aggregation.
Solution Approach 2:
The patent introduces synthetic gap-filling entries as intermediary elements that bridge the gaps between existing route entries. These intermediary entries enable the creation of contiguous aggregated ranges while preserving the original routing information, acting as mediators that allow aggregation without sacrificing forwarding accuracy.
Data Source
AI summary
A subset of route entries having the same next hop is identified in a route table. The subset of entries falls within a range of prefixes. Gaps in the subset of route entries that prevent the subset from being contiguous are identified. The gaps in the subset are filled with route entries to make the subset contiguous. All of the route entries in the contiguous subset of route entries have the same next hop, thus the contiguous subset can be aggregated into a single route entry in a forwarding table. For each gap-filling entry added to the route table, an additional route entry having forwarding priority over the gap-filling entry is added to the forwarding table.