VRF Instance Selector for Traffic Distribution Granularity
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Solution Overview
Problem
In large IP networks with many interfaces, existing routers struggle to distribute traffic effectively over all available egress interfaces due to insufficient hash values generated from packet headers, limiting the granularity of routing and traffic balancing.
Innovation Solution
The proposed solution leverages virtual routing and forwarding (VRF) functionality by selecting a VRF instance for each packet based on both the ingress indicator and an additional set of header data, increasing the granularity of egress interface selection and traffic distribution by mapping packets to multiple VRF instances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional hash-based routing is used with limited header fields, then the routing mechanism is simple, but the granularity of egress interface selection is insufficient for effective traffic distribution across many interfaces
Solution Approach 1:
The patent segments the routing decision process into multiple independent components: VRF instance selection based on ingress indicator and header fields, hash calculation on selected header fields, and egress interface selection from multiple paths. This segmentation allows each component to operate with appropriate granularity without overwhelming complexity.
Solution Approach 2:
The patent adds a new dimension to routing by introducing VRF instance selection as an intermediate layer between traditional hash-based routing and egress interface selection. This dimensional addition enables traffic distribution across multiple VRF instances, each with its own set of egress interfaces, thereby increasing overall granularity without requiring complete redesign of the routing mechanism.
2Productivity
If multiple VRF instances are introduced to increase routing granularity, then traffic distribution capability is improved, but the complexity of routing tables and forwarding logic increases
Solution Approach 1:
The patent makes the VRF routing tables universal by designing them to serve dual purposes: traditional VRF routing functions and traffic distribution across multiple egress interfaces. The same VRF routing table structure is used for both exact-match VRF routing and hash-based path selection, eliminating the need for separate complex data structures.
Solution Approach 2:
The patent introduces the VRF instance as an intermediary layer between the ingress packet and the final egress interface selection. This intermediary enables traffic to be distributed across multiple VRF instances based on header field hashing, while each VRF instance maintains its own routing table, thereby managing complexity through hierarchical organization rather than flat complexity.
3Measurement precision
If hash calculation is performed on all header fields, then the distribution granularity is maximized, but the processing overhead and computational cost increase significantly
Solution Approach 1:
The patent extracts only the necessary header fields for hashing purposes, rather than processing all header fields. By selecting specific fields (such as source/destination IP addresses and ports) for hash calculation, the system achieves sufficient distribution granularity while minimizing computational overhead and energy consumption.
Solution Approach 2:
The patent applies partial action by performing hash calculation on a subset of header fields rather than all fields. This partial processing provides adequate traffic distribution granularity for most scenarios while significantly reducing the computational burden compared to hashing all header fields, representing an optimal balance between precision and efficiency.
Data Source
AI summary
Communication apparatus includes a plurality of interfaces and routing logic coupled between the interfaces. The routing logic includes a parser, which extracts header data from selected fields of each data packet received from the network through an ingress interface. At least one hash calculator computes a hash over a first set of the header data extracted by the parser from each received data packet. A virtual routing and forwarding (VRF) instance selector selects a VRF instance for each received data packet responsively to both an ingress indicator associated with the received data packet and a second set of the header data extracted by the parser from the received data packet. A lookup engine selects an egress interface responsively to the selected VRF instance and the computed hash. Forwarding and switching logic forwards the data packet to the selected egress interface for transmission to the network.