Service Function Forwarding via IP Tunnel Encapsulation
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Solution Overview
Problem
Existing methods for service function forwarding in data communication networks are limited in conveying ancillary information, performing adaptive routing, and using conventional packet forwarding mechanisms, requiring specialized equipment and being inefficient in handling service function chaining.
Innovation Solution
A method and apparatus that utilize conventional IP routing and forwarding mechanisms to forward packets along a service function path by encapsulating data packets within tunnel packets, inserting a service path descriptor and service context information into the header, allowing for efficient routing and processing using commercial off-the-shelf routers and switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If specialized equipment is used for service function forwarding, then service function chaining can be implemented, but device complexity increases and conventional packet forwarding mechanisms cannot be used
Solution Approach 1:
The patent introduces a service function header as an intermediary data structure that bridges conventional IP routing and service function chaining. This header contains service path descriptors and context information, allowing standard routers to forward packets through service functions without requiring specialized equipment. The service function header acts as a mediator that carries service-specific information through the network using existing IP infrastructure.
2Loss of information
If service function paths are implemented without encapsulation, then packet forwarding is simpler, but ancillary information and service context cannot be conveyed
Solution Approach 1:
The patent implements nesting by encapsulating the service function header within the IP packet structure. The service path descriptor and context information are nested within fields of the IP header (specifically utilizing source and destination address fields), allowing ancillary information to be conveyed without adding separate external data structures. This nested approach integrates service function information into the existing packet format.
3Device complexity
If conventional IP routing mechanisms are used for service function forwarding, then device complexity is reduced, but adaptive routing within the service function domain is limited
Solution Approach 1:
The patent introduces dynamic routing capabilities through the service path descriptor field in the service function header. This descriptor can be modified at different points along the service function path, enabling adaptive routing decisions. Service function forwarders can dynamically update the service path descriptor based on network conditions, service policies, or load balancing requirements, allowing conventional routers to perform adaptive routing without specialized equipment.
Data Source
AI summary
Solutions to packet forwarding along a service function path (SFP) by using packet-based transport are provided, where the destination address field in the transport tunnel packet header designates the SFP and the source address field contains the service context. Forwarding of packet flows in different SFPs is simplified by using conventional packet routing and forwarding mechanisms and commercial off-the-shelf routers and switches. For example, route aggregation, load balancing, equal cost multipath routing, and fast path restoration can be applied to service function paths.