SDN Controller Packet Payload Forwarding Path Indication
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Solution Overview
Problem
In Software-Defined Networking (SDN), the modification of packet headers by services like firewalls and NATs leads to loss of forwarding path information, preventing the SDN controller from identifying the original forwarding path and resulting in abnormal packet forwarding.
Innovation Solution
The SDN controller modifies packets to include forwarding path indication information in the valid payload, ensuring that even if the packet header is altered, the original forwarding path can be identified and the packet can be forwarded correctly by embedding this information within the packet's payload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the packet header is modified by services (firewall, NAT, LB), then the packet can be processed and modified according to service requirements, but the forwarding path information is lost and the SDN controller cannot identify the original forwarding path
Solution Approach 1:
The patent divides the packet into two distinct parts: the header (which can be modified by services) and the payload (which carries forwarding path indication information). By segmenting the packet this way, the forwarding path information is isolated in the payload, protecting it from modification while allowing the header to be freely modified by services like firewall, NAT, and load balancing.
Solution Approach 2:
The patent introduces forwarding path indication information as an intermediary element within the packet payload. This intermediary carries the forwarding path information independently of the packet header, allowing services to modify the header without affecting the forwarding path identification capability.
2Reliability
If the packet header is modified by services, then the packet can undergo security inspection and address translation, but the SDN controller cannot identify the forwarding path and packet forwarding becomes abnormal
Solution Approach 1:
The patent segments the packet into header and payload portions, placing forwarding path indication information in the payload. This allows services to reliably modify the header for security and translation functions while the payload preserves the forwarding path information needed for controller control.
Solution Approach 2:
The patent implements a feedback mechanism where the SDN controller receives packets with modified headers but can still identify the original forwarding path through the forwarding path indication information in the payload. This feedback allows the controller to maintain awareness of the forwarding path despite header modifications by services.
3Loss of information
If forwarding path indication information is carried in the packet payload, then the original forwarding path can be maintained despite header modifications, but the packet structure becomes more complex
Solution Approach 1:
The patent applies segmentation by separating the packet into header and payload components, with the payload containing both the original payload data and the forwarding path indication information. This structured segmentation organizes the complexity rather than creating it, making the packet structure more manageable.
Solution Approach 2:
The patent makes the packet payload multi-functional by having it serve both as the original payload carrier and as the container for forwarding path indication information. This universal use of the payload area avoids adding separate structural elements, thereby limiting the increase in packet structure complexity.
Data Source
AI summary
A packet processing method, including receiving a first packet from a first switch, where the first packet belongs to a service flow that flows from a first device to a second device, determining a service chain through which the service flow passes, determining a forwarding path of the service flow according to the service chain through which the service flow passes, modifying the first packet to obtain a second packet, where the second packet belongs to the service flow, and a valid payload of the second packet includes a valid payload of the first packet and forwarding path indication information, generating a first flow table according to the forwarding path of the service flow, controlling a communications interface to send the first flow table to the first switch, and sending the second packet to the first switch.