Load Balancing Fragmented Tunnel Packets via Inner Header Extraction
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Solution Overview
Problem
Conventional load-balancing systems in computer networks face challenges in balancing tunneled traffic due to IP packet fragmentation, where the inner IP header is lost in subsequent fragments, preventing accurate forwarding of non-first fragments and degrading network functionality.
Innovation Solution
A system and method for load balancing network traffic that involves receiving tunnel frames, reassembling fragmented packets to determine the inner IP header, and applying traffic policies, including fragmenting packets to meet MTU restrictions and inserting headers with subscriber data, to ensure accurate routing and quality of service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IP packet fragmentation is performed to meet MTU restrictions, then packets can be transmitted across network links, but the inner IP header is lost in subsequent fragments making load balancing impossible
Solution Approach 1:
The patent applies preliminary action by extracting and preserving the inner IP header from the first fragment before fragmentation occurs. The system stores this header information in a buffer associated with the outer IP header, so that when subsequent fragments arrive, the inner IP header can be restored for load balancing decisions without being present in the fragment data itself.
Solution Approach 2:
The patent introduces an intermediary mechanism - a buffer that associates outer IP header information with the preserved inner IP header. This intermediary structure allows the system to maintain load balancing capability by providing access to inner IP header information without requiring it to be physically present in each fragment, thus mediating between the fragmentation process and load balancing requirements.
2Measurement precision
If load balancing is performed on inner IP header, then accurate traffic routing is achieved, but fragmented packets cannot be properly balanced since inner header is unavailable
Solution Approach 1:
The system performs preliminary extraction of the inner IP header from the first fragment and stores it in an associated buffer before processing subsequent fragments. This preliminary action ensures that load balancing decisions can be made with full inner IP header information available, maintaining measurement precision without requiring complex real-time header extraction from each fragment.
Solution Approach 2:
The patent creates a copy of the inner IP header from the first fragment and stores it in a buffer associated with the outer IP header. This copying mechanism allows the system to use the preserved header copy for load balancing decisions on all fragments, eliminating the need to perform complex operations on each individual fragment while maintaining accurate load balancing.
3Reliability
If full packet information is required for network functions, then complete functionality is maintained, but fragmented packets without full headers experience degraded functionality
Solution Approach 1:
The system performs preliminary preservation of the inner IP header from the first fragment, storing it in a buffer associated with the outer IP header. This ensures that when fragmented packets reach network functions requiring full packet information, the inner IP header can be restored, maintaining network function reliability without requiring the complete original packet to be present.
Solution Approach 2:
The patent introduces an intermediary buffer that associates outer IP header information with the preserved inner IP header. This intermediary structure allows network functions to access complete packet information by combining the outer header with the preserved inner header, maintaining full functionality even when packets arrive as fragments without the original complete header information.
Data Source
AI summary
A method and system for load balancing are provided. The method includes: receiving a tunnel frame from a traffic flow; determining whether the tunnel frame is one of a plurality of frames from a packet; if the frame is one of a plurality of frames, reassembling the plurality of frames associated with the packet to determine an inner IP header; load balancing the packet based on the inner IP header; and applying traffic policies to the packet. The system has: a traffic interface configured to receive a tunnel frame from the traffic flow; a subscriber load balancer configured to determine whether the tunnel frame is one of a plurality of frames from a packet; at least one IP reassembly engine configured to reassemble the plurality of frames associated with the packet to determine an inner IP header; and at least one flow policy engine configured to load balance the packet based on the inner IP header; and apply traffic policies to the packet.