Infrastructure-Exclusive Service Forwarding for Scalable Network Overlays
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Solution Overview
Problem
Existing methods for forwarding traffic through service functions in communications networks face complexities in deployment and operation due to numerous forwarding touch points, scale challenges, and violations of operational environment policies, particularly due to errors in service function state management.
Innovation Solution
The implementation of infrastructure-exclusive service forwarding separates service overlays into service-function and infrastructure overlays, limiting forwarding state manipulation to forwarding elements and freeing service functions from decision-making, allowing for scalable and secure packet forwarding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If service functions are involved in making forwarding decisions, then service delivery flexibility is improved, but device complexity and scale challenges worsen
Solution Approach 1:
The patent segments the forwarding decision-making process by introducing a service chain controller that separates control plane functions from data plane forwarding. The controller manages service chain policies and forwarding decisions centrally, while network switches handle only simple forwarding based on controller instructions. This segmentation reduces the complexity at each forwarding touch point while maintaining service delivery flexibility through centralized control.
2Adaptability or versatility
If service functions manage forwarding state, then service customization is improved, but reliability worsens due to errors and unintentional modifications
Solution Approach 1:
The patent extracts forwarding state management from service functions and consolidates it in the service chain controller. The controller maintains the authoritative forwarding state and distributes it to network switches, preventing service functions from making errors or unintentional modifications. This extraction maintains service customization capabilities through controller policies while improving reliability by centralizing state management.
3Adaptability or versatility
If multiple forwarding touch points are used for service chaining, then service function coverage is improved, but ease of operation worsens due to deployment complexity
Solution Approach 1:
The patent introduces a service chain controller as an intermediary that simplifies deployment operations. The controller automatically programs network switches with forwarding rules based on service chain requirements, eliminating manual configuration at each forwarding touch point. This intermediary maintains comprehensive service function coverage while significantly reducing deployment complexity through automated control plane operations.
Data Source
Figure 1A~1C
Figure 2A~2B
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AI summary
A method is provided in one example embodiment and includes receiving at a network element a packet including a Network Services Header ("NSH"), in which the NSH includes an Infrastructure ("I") flag and a service path header comprising a Service Index ("SI"), and a Service Path ID ("SPI") and determining whether the I flag is set to a first value. The method further includes, if the I flag is set to the first value, setting the I flag to a second value and forwarding the packet to the service function that corresponds to the SI for processing. The method still further includes, if the I flag is not set to the first value, decrementing the SI and making a forwarding decision based on a new value of the SI and the SPI.