Policy Based Routing Data Processing Pipeline

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Solution Overview

Problem

The inefficient use of memory in network elements due to the need for separate routing tables for each policy map in policy-based routing (PBR) systems, which leads to suboptimal memory utilization.

Innovation Solution

Implementing a data processing pipeline that uses a longest prefix match lookup table to store routing entries for PBR, where special entries are created in the LPM lookup table for different virtual routing and forwarding instances, using a key formed by prepending an address indicator to the PBR policy map identifier, allowing for efficient lookup and determination of the next hop interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate routing tables are used for each policy map in policy-based routing, then routing decisions can be made based on different packet characteristics, but memory utilization becomes inefficient

Engineering Contradiction:

Improverouting decision flexibilityVSAvoidmemory utilization

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges multiple separate routing tables for different policy maps into a single unified routing table. Each entry in the unified table includes a policy map identifier field that indicates which policy map the entry belongs to. This consolidation eliminates redundant memory storage while maintaining the ability to perform policy-based routing decisions by examining the policy map identifier during packet processing.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The unified routing table serves multiple functions by supporting routing decisions for multiple different policy maps simultaneously. The table structure is designed to be universal, accommodating entries from various policy maps through the inclusion of policy map identifier fields, allowing a single data structure to replace multiple specialized tables.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple separate tables are maintained for different policy maps, then policy-based routing can be implemented, but the device complexity increases

Engineering Contradiction:

Improvepolicy map supportVSAvoidtable management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple policy map-specific routing tables into one unified table structure. This merging reduces the complexity of managing multiple separate tables, including table creation, deletion, and synchronization operations. The unified table simplifies the overall data structure management while preserving support for multiple policy maps through identifier fields in each entry.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10673757B2System and method of a data processing pipeline with policy based routing

Publication Date: 2020.06.02 ARISTA NETWORKS INC

AI summary

A method and apparatus of a network element that processes data by a network element with a data processing pipeline is described. In an exemplary embodiment, the network element receives network data and performs a policy-based routing lookup using one or more characteristics of the network data to retrieve a next hop identifier. In addition, the network element generates a key for the next hop identifier and performs a longest prefix match lookup to retrieve a forwarding result. The network element further determines a next hop interface based on the forwarding result.