Inter-domain Service Function Chaining via Border Node Header Rewriting
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Solution Overview
Problem
Conventional service chaining techniques are limited to a single administrative domain, making it difficult to span service chains across multiple domains without address leaking and maintaining service function order, especially with the increasing distribution of cloud-based services.
Innovation Solution
The method involves using a service function path identifier and service index to modify packets at border nodes, allowing them to be forwarded across multiple administrative domains, with header rewrite as a service function to direct traffic correctly, regardless of service function location or order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If service chains are extended across multiple administrative domains, then service coverage and versatility are improved, but address leaking and loss of privacy between domains occur
Solution Approach 1:
The patent introduces border nodes as intermediary entities between administrative domains. These border nodes perform header rewriting operations that translate service function path identifiers and service indices across domain boundaries, enabling inter-domain service chaining while preventing direct address exposure between domains. The border node acts as a mediator that maintains service chain continuity without requiring domains to share internal addressing information.
2Adaptability or versatility
If service chains span multiple administrative domains, then service distribution flexibility is improved, but maintaining service function order becomes more difficult
Solution Approach 1:
The patent applies preliminary action by pre-establishing service function path identifiers and service indices that encode the required service function order. Border nodes are pre-configured with rewriting rules that automatically enforce the correct service function sequence across domain boundaries. This preliminary setup eliminates the need for complex real-time coordination to maintain service function ordering.
Solution Approach 2:
The patent uses parameter changes by modifying packet headers at border nodes through rewriting operations. The service function path identifier and service index parameters are transformed as packets cross domain boundaries, allowing the same service chain to be represented with different parameters in different domains while maintaining the logical service function order.
3Reliability
If header rewriting is performed at border nodes, then correct service function application is ensured, but processing complexity at border nodes increases
Solution Approach 1:
The patent extracts the complex header rewriting logic from border nodes and relocates it to dedicated service function chain control entities. Border nodes only need to perform simple lookups and replacements based on pre-configured rules, significantly reducing their processing complexity. The service function path identifier and service index manipulation is extracted as a separate control plane function.
Data Source
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AI summary
In one embodiment, a method includes receiving a packet in a service function chain at a network device located at a border of a first administrative domain, the packet comprising a service function path identifier and a service index, processing the packet at the network device, wherein processing comprises modifying the packet based on the service function path identifier and the service index to direct the packet to a second administrative domain, and forwarding the packet from the network device to the second administrative domain for processing in the service function chain. The service function chain extends over the first and second administrative domains. An apparatus and logic are also disclosed herein.