Routing Table Broadcast Flag Mechanism for IP Packet Processing Bottlenecks

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Solution Overview

Problem

The processing of outgoing IP packets to verify whether the destination IP address is a broadcast address is resource-intensive, especially in systems with many IP aliases, leading to bottlenecks in multiprocessor systems due to the need for locks on the interface and extensive comparisons.

Innovation Solution

The method involves using flags in the routing table to determine if a packet is to be broadcast, reducing the need for per-packet comparisons and avoiding bottlenecks by checking RTF_BROADCAST and RTF_HOST flags to identify broadcast packets, thus minimizing the processing required for each packet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If per-packet verification of broadcast addresses is performed, then broadcast traffic is correctly identified, but processing time and resource usage increase significantly

Engineering Contradiction:

Improvebroadcast traffic identification accuracyVSAvoidpacket processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-computing and storing broadcast address verification results in a routing table before packets arrive. The routing table is populated with broadcast address information in advance, allowing the system to quickly check pre-computed values rather than performing expensive per-packet verification. This resolves the contradiction by maintaining reliable broadcast identification through pre-computed routing tables while dramatically reducing packet processing time through simple table lookups.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If per-packet comparisons with multiple broadcast addresses are performed, then accurate broadcast detection is achieved, but resource usage and processing overhead increase

Engineering Contradiction:

Improvebroadcast address detection accuracyVSAvoidprocessing resource usage

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent performs the expensive comparison operations in advance by pre-computing broadcast address matches and storing the results in routing table entries. During packet processing, the system only needs to compare the destination address against pre-computed routing table entries rather than performing multiple comparisons with each broadcast address. This maintains precise broadcast detection while minimizing processing resource usage during actual packet handling.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent creates a copy of broadcast address verification information in the routing table structure. Instead of directly comparing packets against multiple broadcast addresses, the system copies the essential verification information into routing table entries that can be quickly consulted. This copying approach maintains detection accuracy while reducing the computational burden during packet processing.

Inventive Principle:

Principle #26Copying

3Stability of the object's composition

If locks on the interface are required for verification, then data consistency is maintained, but bottlenecks occur in multiprocessor systems

Engineering Contradiction:

Improveinterface data consistencyVSAvoidpacket processing throughput

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent resolves the locking bottleneck by performing all verification-related computations in advance and storing results in the routing table. During packet processing, the system only needs to read pre-computed routing table entries rather than performing verification operations that require locks. This maintains data consistency through the immutable routing table structure while eliminating bottlenecks in multiprocessor systems by removing the need for interface locks during packet handling.

Inventive Principle:

Principle #10Preliminary action

4Measurement precision

If extensive comparisons are performed to verify destination IP addresses, then accurate broadcast identification is achieved, but processing speed decreases

Engineering Contradiction:

Improvedestination address verification accuracyVSAvoidpacket processing speed

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent applies preliminary action by pre-computing all necessary address verification information and storing it in routing table entries before packets arrive. The routing table contains pre-calculated broadcast address matches and other verification data, allowing the system to achieve accurate destination address verification through simple table lookups rather than extensive per-packet comparisons. This maintains verification accuracy while dramatically improving packet processing speed.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7734812B2Method and apparatus for processing outgoing internet protocol packets

Publication Date: 2010.06.08 D-LINK CORP

AI summary

A method, apparatus, and computer instructions for processing packets in a network layer. A packet is received for transmission in which the packet includes a destination address. A routing entry for the destination address is identified. A determination is made as to whether a flag indicating the packet is to be broadcast has been set in the routing entry. Header information is placed in the packet in which the header information indicates that the packet is a broadcast packet in response to the flag being set.