SFF Packet Encapsulation for Buffer-Free SR Service Chaining
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Solution Overview
Problem
Existing packet processing methods for service function chains (SFC) using segment routing (SR) require significant resource overheads due to the need for buffer spaces to store and maintain segment routing headers, leading to inefficient resource utilization.
Innovation Solution
A method where the service function forwarder (SFF) modifies the packet encapsulation format by encapsulating the IP header in the outer layer of the segment routing header, allowing the original SR encapsulation format to be restored without the need for buffer storage, thereby reducing resource overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the dynamic proxy manner is used to support SR-based SFC, then the SFC can be supported with SR encapsulation, but the SFF needs to generate and maintain buffer space to store stripped segment routing headers, resulting in huge resource overheads
Solution Approach 1:
Instead of stripping the SR header before forwarding to SF and then restoring it later (which requires buffer storage), this patent inverts the approach by keeping the SR header in place and moving the IP header to the outer layer. This allows the SR header to remain attached to the packet throughout the forwarding process without requiring separate buffer storage, thereby resolving the contradiction between SR-based SFC support and buffer space consumption
Solution Approach 2:
The patent applies nesting by placing the IP header inside the SR header structure, and then nesting the SR header within the outer IP header. This nested structure allows the SR header to be carried along with the packet without requiring separate buffer allocation, as it becomes an integrated part of the packet structure rather than a separate entity that needs storage
Data Source
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AI summary
This application provides a packet processing method and apparatus, and a system. In this application, when receiving a packet in an SR encapsulation format, an SFF modifies the encapsulation format of the packet, encapsulates an IP header in the packet in an outer layer of an SR header, and sends a modified packet to an SF. In a process in which the packet is forwarded from the SFF to the SF, the packet still carries the SR header. Therefore, when the packet is subsequently returned from the SF to the SFF, the SFF can restore the original SR encapsulation format by using the SR header carried in the packet. In this way, a limitation that a buffer space used to store an SRH needs to be generated and maintained before an SR encapsulation format can be restored is eliminated, huge resource overheads caused by generating and maintaining the buffer space used to store the SRH are avoided, and resource overheads are reduced.