Allocation Node LPM Matching for Distributed Route Search
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Solution Overview
Problem
The efficiency of route searching mechanisms in distributed routers is relatively low due to uneven distribution of routing tables and hash conflicts, leading to reduced overall routing efficiency.
Innovation Solution
Routing tables are distributed across multiple searching nodes, and both allocation and searching nodes utilize the Longest Prefix Matching (LPM) principle to avoid conflicts and improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If routing tables are distributed using hash keys in a distributed router, then routing table distribution is achieved, but hash conflicts occur causing false hits and reduced routing efficiency
Solution Approach 1:
An allocation node is introduced as an intermediary between the ingress node and searching nodes. The allocation node performs initial LPM matching to determine which searching node should handle the routing lookup, preventing hash conflicts and false hits while maintaining efficient distributed routing
2Productivity
If routing tables are distributed across multiple searching nodes, then routing table pressure is reduced, but uneven distribution occurs leading to some nodes bearing more pressure
Solution Approach 1:
The system changes the matching parameter from hash keys to LPM (Longest Prefix Match) keys. This parameter change enables more uniform distribution of routing table pressure across searching nodes while maintaining high route searching efficiency through hierarchical LPM matching
3Extent of automation
If hash keys are used for distributed route searching, then route searching can be performed in distributed manner, but extra mechanisms are required to resolve hash conflicts
Solution Approach 1:
The conflict resolution mechanism is extracted and separated from the route searching process. The allocation node handles all LPM matching and searching node selection before packets reach the searching nodes, eliminating the need for complex conflict resolution mechanisms at the searching nodes themselves
Data Source
Figure 1a
Figure 1b~2
Figure 3A
AI summary
A route searching method and apparatus, an allocation node, a searching node, and an ingress node are provided. The method includes: receiving, by an allocation node, a destination IP address of a packet sent by an ingress node, where an allocation table on the allocation node includes a match item field and a searching node number field, the match item field is a prefix corresponding to a root node of a prefix subtree, and the searching node number field is a physical box number of a searching node on which routing information of the prefix subtree is located; performing, by the allocation node, matching of the match item field in the allocation table according to the destination IP address in an LPM principle; if the destination IP address successfully matches a first match item field in the allocation table, obtaining, by the allocation node, a physical box number of a first searching node on which routing information of a first prefix subtree corresponding to the first match item field is located; and sending, by the allocation node, the destination IP address to the first searching node.