Tunnel Packet Header Mapping for Consistent Flow Distribution
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Solution Overview
Problem
Existing network packet distribution systems struggle to ensure that packets from the same source device are processed by the same destination, especially in tunneling protocols where the source IP address changes, leading to potential processing out of order and unintended consequences.
Innovation Solution
Implement downstream destination selection for tunnel packets based on fixed header packet values, such as the UDP destination port or VPN IP address, using a network device driver to access a data structure and select a consistent downstream destination based on these values, ensuring packets from the same source device are always processed by the same destination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If network packets are distributed over multiple potential destinations for parallel processing, then processing throughput is improved, but packets from the same flow may be processed by different destinations leading to out-of-order processing
Solution Approach 1:
The patent changes the parameter used for destination selection from source IP address (which changes in tunneling scenarios) to fixed header values such as UDP destination port or VPN IP address that remain constant for packets from the same source device. This parameter change ensures consistent destination selection while maintaining load distribution across multiple destinations.
Solution Approach 2:
The patent introduces an intermediary data structure that maps fixed header values to downstream destinations. This intermediary layer decouples the packet flow identification from the destination selection, allowing packets from the same flow to consistently map to the same destination while still enabling parallel processing across multiple destinations.
2Device complexity
If source IP address is used for destination selection in tunneling protocols, then destination selection is simplified, but packets from the same source device may be routed to different destinations when source IP changes
Solution Approach 1:
The patent changes the selection parameter from source IP address to fixed header values (UDP destination port, VPN IP address) that remain constant throughout the tunneling session. This resolves the issue where source IP changes cause packets from the same device to be routed to different destinations.
Solution Approach 2:
The patent performs preliminary extraction and hashing of fixed header values at the beginning of packet processing, before destination selection. This preliminary action ensures that the same flow always produces the same destination selection key, maintaining consistency even when other packet fields change.
Data Source
AI summary
A network device driver (NDD) associated with a network interface device (NID) of a computing device processes a tunnel packet received by the NID and originating from a source device. The tunnel packet includes a tunnel packet header, a user datagram protocol (UDP) header, and a payload including a Transmission Control Protocol/Internet Protocol (TCP/IP) packet. The NDD accesses a data structure that corresponds to the NID. The NDD extracts a value from a field of the tunnel packet based on information in the tunnel packet and on information in the data structure. The NDD selects, based on the value, a first downstream destination from a plurality of downstream destinations operable to further process the tunnel packet, and causes the tunnel packet to be subsequently processed by the first downstream destination.