Network Device Trunk Group Port Selection Hashing
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Solution Overview
Problem
Current network devices face challenges in efficiently transmitting packets across trunk groups, particularly in distributing packets across multiple physical ports without duplication and ensuring redundancy, especially when dealing with broadcast or multicast packets.
Innovation Solution
The implementation of a network device architecture that includes an ingress module, Memory Management Unit (MMU), and egress module, which uses a centralized ingress pipeline architecture and trunk group tables to dynamically select physical ports for packet transmission, employing hashing algorithms to distribute packets across trunk ports based on packet characteristics and load sharing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If packets are transmitted across trunk groups through dynamic port selection, then bandwidth utilization is improved, but packet duplication may occur
Solution Approach 1:
The patent implements a feedback mechanism where the ingress module receives information from the egress module about which physical ports were selected for packet transmission. This feedback allows the ingress module to track packet distribution across trunk ports and prevent duplication by adjusting subsequent packet routing decisions based on previous transmission patterns.
Solution Approach 2:
The patent replaces traditional mechanical switching mechanisms with a hashing-based port selection system. The ingress module uses hash functions to deterministically select physical ports from the trunk group, providing consistent and duplication-free packet distribution across multiple ports without requiring complex mechanical switching hardware.
2Reliability
If multiple physical ports are combined into a trunk port, then redundancy is improved, but device complexity increases
Solution Approach 1:
The patent makes the ingress module universal by enabling it to handle both single-port and trunk group packet transmission through the same hashing mechanism. The same port selection logic works whether the destination is a single physical port or a group of ports, eliminating the need for separate complexity-heavy management systems for different port configurations.
Solution Approach 2:
The patent changes the parameter of port selection from static (fixed port assignment) to dynamic (hash-based selection). This parameter change allows the system to adapt to different trunk group configurations and failure scenarios automatically, reducing the need for manual configuration and management complexity while maintaining redundancy.
3Productivity
If hashing algorithms are used to distribute packets across trunk ports, then load sharing is improved, but processing overhead increases
Solution Approach 1:
The patent extracts the hashing calculation from the main packet processing path and implements it as a separate, optimized function in the ingress module. This extraction allows the hashing operation to be performed efficiently without blocking other critical packet processing tasks, reducing overall processing overhead while maintaining effective load sharing across trunk ports.
Data Source
AI summary
A network device for selecting a port from a trunk group on which to transmit a multicast packet. The network device includes at least one trunk group including a plurality of physical ports. The network device is connected to at least one other network device by a number of the plurality of physical ports. The network device also includes a table with a plurality of entries, wherein each entry is associated with the number of the plurality of physical ports on the network device. Each entry specifies if a packet should be transmitted on one of the plurality of physical ports. The network device further includes a determiner for determining whether or not an override field is set, a hasher for hashing, based on a result from the determiner, a predefined number of bits from predefined fields in the packet to select one entry in the table, wherein the selected entry is used to identify a destination port and a transmitter for transmitting the packet to the destination port based on results from the one of the determiner or the hasher.