TCP Session Content Enrichment via HTTP Redirect Substitution
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Solution Overview
Problem
In mobile packet core networks, content enrichment of TCP sessions through gateways like GGSN and P-GW can lead to TCP signaling storms due to mismatches in TCP sequence and acknowledgement numbers, causing high CPU utilization and resource wastage when flow information is not properly maintained.
Innovation Solution
A network element, such as a GGSN, uses the HTTP redirect mechanism to eliminate the need for maintaining and altering TCP counters by creating a Redirect URL with a Substitution String, allowing for content enrichment without synchronizing TCP sequence numbers, thus preventing signaling storms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If content enrichment is performed in mobile packet core networks, then upper layer protocol content can be enriched, but TCP signaling storms occur due to mismatches in TCP sequence and acknowledgement numbers
Solution Approach 1:
The patent introduces an intermediary mechanism (HTTP redirect with substitution string) between the mobile device and server that allows content enrichment without directly modifying TCP sequence numbers. The substitution string acts as a placeholder that gets replaced with enriched content while TCP counters remain unchanged, preventing signaling storms.
Solution Approach 2:
The patent segments the content enrichment process into two phases: first, a redirect phase where the substitution string is inserted without affecting TCP counters; second, a content replacement phase where the actual enriched content is substituted. This segmentation allows enrichment functionality while maintaining TCP session integrity.
2Reliability
If TCP sequence numbers are synchronized during content enrichment, then TCP session stability is maintained, but CPU utilization increases due to the overhead of maintaining and altering TCP counters
Solution Approach 1:
The patent extracts the content enrichment function from the TCP layer and implements it at the application layer using HTTP redirects. This separation allows content enrichment to occur without involving TCP counter management, eliminating the CPU overhead associated with synchronizing TCP sequence numbers while maintaining session stability.
Solution Approach 2:
The system uses the existing HTTP redirect mechanism and substitution string infrastructure already present in the network to perform content enrichment. This self-service approach leverages available resources rather than requiring additional CPU-intensive TCP counter synchronization mechanisms.
3Loss of energy
If flow information is not maintained for enriched flows, then resource utilization is reduced, but TCP sequence number mismatches cause signaling storms
Solution Approach 1:
The patent performs preliminary action by inserting the substitution string during the redirect phase before actual content enrichment occurs. This preliminary placeholder ensures that the TCP packet structure is properly formed without requiring the gateway to maintain flow information, preventing signaling storms while reducing resource utilization.
Data Source
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AI summary
A gateway system employing a redirect mechanism at upper layer protocols over Transmission Control Protocol (TCP) in a packet network to circumvent problems related to alteration of TCP sequence number due to header enrichment. The gateway system increases the size of a redirect message by the size of the header enrichment and thereby brings TCP sequence number on both ends in sync despite adding the header enrichment information.