Packet Processing Header Translation for Service Function Compatibility
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Solution Overview
Problem
Existing packet forwarding systems face communication errors when a service function forwarder (SFF) can parse a packet header but the associated service function (SF) device cannot, leading to encapsulation errors and disrupted forwarding.
Innovation Solution
The SFF replaces the unparseable packet header with a parseable one, adding an identifier, processes the packet, and restores the original header upon receipt of the processed packet, using a mapping relationship to ensure compatibility and avoid encapsulation errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SFF forwards the original packet with its native header to the SF device, then the packet forwarding process is simple and fast, but the SF device cannot parse the packet header leading to communication errors
Solution Approach 1:
The patent introduces an identifier field as an intermediary element that bridges the SFF and SF device. The identifier carries mapping information that enables the SF device to parse packet headers it would otherwise be unable to interpret, while allowing the SFF to maintain simple forwarding logic. This intermediary mechanism resolves the contradiction by enabling reliable communication without significantly increasing processing complexity.
Solution Approach 2:
The patent applies preliminary action by pre-establishing mapping relationships between packet headers and identifiers before forwarding occurs. The SFF configures correspondence between packet header types and identifier values in advance, so that when packets are forwarded, the SF device can use the identifier to look up and parse the appropriate header format without complex real-time processing.
2Adaptability or versatility
If the SFF replaces the packet header with a parseable one, then compatibility with SF devices is improved, but encapsulation errors may occur due to query errors in subsequent encapsulation
Solution Approach 1:
The patent implements feedback mechanisms through the identifier field that carries mapping relationship information. This feedback enables the SFF to verify and correct header replacements, ensuring that the replaced header type corresponds to the actual packet content. The identifier acts as a feedback signal that prevents encapsulation errors by confirming the correctness of header replacements.
Solution Approach 2:
The patent uses copying by creating a mapping relationship copy between packet headers and identifiers. Instead of directly modifying packet headers, the system creates identifier copies that reference header types, allowing the SF device to work with simplified packet formats while maintaining accurate header information through the identifier reference.
3Manufacturing precision
If the SFF stores and queries packet headers locally, then accurate header replacement is achieved, but storage and query overhead increases
Solution Approach 1:
The patent applies parameter changes by transforming the packet header replacement problem into an identifier-based lookup problem. Instead of storing and querying complex packet header data structures, the system uses simplified identifier parameters that map to header types. This parameter transformation reduces storage requirements and query complexity while maintaining accurate header replacement.
Data Source
AI summary
A packet processing method, to improve a success rate of packet forwarding. The method implemented by a service function forwarder (SFF) includes: receiving a first packet; replacing a first packet header of the first packet with a second packet header to obtain a second packet, where the second packet includes a first identifier uniquely identified the first packet header; sending the second packet to a service function (SF) device; receiving a third packet from the SF, the third packet includes the first identifier; replacing a third packet header of the third packet with the first packet header to obtain a fourth packet; and sending the fourth packet to a next-hop node.