Correlation Cookie for Service Function Chain Metadata Preservation
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Solution Overview
Problem
Conventional methods for processing packets according to a service function chain (SFC) require additional processing time and resources when service function providers modify the packet flow identity, leading to metadata removal and subsequent reclassification needs.
Innovation Solution
Implementing a correlation cookie that associates packets with an SFC, encoding it into the packet, and storing information to restore metadata when the packet is received, thereby maintaining the SFC without reclassification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If service function providers modify the packet flow identity, then service functions can be performed on the packet, but metadata is removed and reclassification is required
Solution Approach 1:
The patent applies preliminary action by inserting a correlation cookie into the packet before the service function provider modifies the flow identity. This correlation cookie preserves the service function chain metadata independently of the flow identity changes, allowing the metadata to be restored after modification without requiring reclassification, thus eliminating the time loss associated with reclassification while maintaining service function capability
2Adaptability or versatility
If service function providers modify the packet flow identity, then service functions can be performed on the packet, but additional processing resources are required for reclassification
Solution Approach 1:
The correlation cookie is inserted in advance before flow identity modification, carrying the service function chain metadata independently. This preliminary action ensures that when the service function provider modifies the packet, the metadata is already preserved in the correlation cookie, eliminating the need for resource-intensive reclassification processing while maintaining full service function capability
Solution Approach 2:
The correlation cookie acts as an intermediary mechanism that decouples the flow identity modification from the metadata preservation. It serves as a mediator that carries the service function chain information independently of the packet's flow identity, allowing service functions to be performed while avoiding the need for additional reclassification processing resources
3Adaptability or versatility
If metadata is removed from the packet, then service function providers can modify flow identity, but the service function chain is broken and reclassification is needed
Solution Approach 1:
The correlation cookie is inserted before the service function provider modifies the flow identity, preserving the service function chain metadata independently. This preliminary action ensures that even when metadata is removed during flow identity modification, the service function chain integrity is maintained through the correlation cookie, which can be used to restore the metadata and maintain chain reliability without reclassification
4Reliability
If packets are reclassified to reestablish SFC, then service function chain is restored, but network overhead increases
Solution Approach 1:
The correlation cookie is inserted in advance before flow identity modification, carrying the service function chain metadata. This preliminary action prevents metadata loss and eliminates the need for reclassification to restore the SFC, thereby avoiding the network overhead associated with reclassification while maintaining SFC reliability
Data Source
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AI summary
According to examples, an apparatus may include a processor and a memory on which is stored machine readable instructions. The instructions may cause the processor to intercept a packet from a downstream service function classifier, in which the packet includes metadata that specifies an ordered set of service functions within a service function chain to be implemented on the packet, generate a correlation cookie that associates the packet with the service function chain, and encode the correlation cookie into the packet. The instructions may also cause the processor to store the correlation cookie and the metadata in a cache to correlate the correlation cookie and the metadata and send the packet with the encoded correlation cookie to the service function provider.