Hardware Packet Forwarding Table for Data Center Traffic Management

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Solution Overview

Problem

Traditional packet-forwarding systems in server groups are limited by software dependencies, which restrict them from achieving line rate data transmission speeds and are constrained by memory capacity, limiting the number of sessions they can process.

Innovation Solution

A hardware-based packet forwarding system that uses a packet forwarding table to map hash values from packet headers to servers, eliminating the need for software-based session management and enabling line-rate traffic management across servers without relying on session tables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If software-based traffic management is used, then session management capability is improved, but data transmission speed deteriorates due to inability to achieve line rate

Engineering Contradiction:

Improvesession management capabilityVSAvoiddata transmission speed

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent segments the traffic management system into two independent parts: a hardware-based forwarding plane that handles packet switching at line rate, and a separate control plane that manages session information. This segmentation allows the forwarding operations to proceed at full speed while session management handles complexity independently, resolving the contradiction between speed and session management capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism (hardware forwarding tables with hash-based lookup) that mediates between incoming packets and session management logic. The hardware component acts as an intermediary that can quickly determine forwarding decisions based on hash values without requiring full software-based session table lookups, thereby maintaining line rate performance while still enabling session management.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If software-based session tables are used, then session tracking capability is improved, but system capacity deteriorates due to memory constraints

Engineering Contradiction:

Improvesession tracking capabilityVSAvoidsystem capacity

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent extracts the session table management function from the main forwarding path and implements it as a separate, optional component. The core forwarding operation does not depend on software session tables but uses hardware-based hash lookup, allowing the system to maintain high capacity while providing session tracking capability when needed through a dedicated control plane component.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental parameter of how forwarding decisions are made - from software-based session table lookups to hardware-based hash value indexing. This parameter change transforms the system from being memory-constrained to being limited only by hardware resources, dramatically increasing system capacity while maintaining session tracking capability through alternative mechanisms.

Inventive Principle:

Principle #35Parameter changes

3Speed

If hardware-based forwarding is used, then data transmission speed is improved to line rate, but session management capability deteriorates due to lack of software processing

Engineering Contradiction:

Improvedata transmission speedVSAvoidsession management capability

Core Design Contradiction:

SpeedVSAdaptability or versatility

Solution Approach 1:

The patent segments the system into a hardware forwarding plane that operates at line rate and a separate software control plane that provides session management. This segmentation allows each component to specialize - hardware for speed and software for complexity management - resolving the contradiction between speed and session management capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces hardware forwarding tables with hash-based lookup as an intermediary between incoming packets and the destination. This intermediary provides fast hardware-based forwarding while the control plane can still access and manage session information when needed, combining the benefits of both hardware speed and software flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8867341B2Traffic management of client traffic at ingress location of a data center

Publication Date: 2014.10.21 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A switch device includes a packet-forwarding table for providing traffic management across servers in a server group. Each table entry maps a hash value to a server in the server group. A hash value is computed from data in one or more fields in the header of a received packet. The computed hash value is used as an index into the packet-forwarding table to access a table entry and to identify from the table entry the server in the server group to which the table entry maps the computed hash value. The switch device forwards the packet to the identified server. Implementing traffic management decisions in hardware enables packet switching at the line rate of the switch ports. In addition, the hardware-based traffic management performed by the switch device eliminates session tables and the memory to store them, enabling the switch device to handle an unlimited number of client connections.