Dual-TCAM Network Address Translation Rule Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current network address translation (NAT) systems require significant TCAM resources due to the need to store both NAT and access control list (ACL) rules in a single memory, leading to inefficient scaling and increased complexity as the number of NAT mappings and ACL filters grows.
Innovation Solution
Implementing a dual-TCAM configuration where NAT rules and ACL filter rules are stored separately in distinct TCAMs, allowing for efficient filtering and translation of packets based on ACL-qualified NAT mappings, reducing the number of TCAM entries required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NAT and ACL rules are stored in a single TCAM, then the system can perform filtering and translation, but the TCAM resource consumption increases quadratically with the number of NAT mappings and ACL filters
Solution Approach 1:
The patent divides the single TCAM into two separate TCAMs: one dedicated to storing ACL filter rules and another dedicated to storing NAT translation rules. This segmentation allows the system to independently manage and optimize each rule type, reducing the quadratic growth of TCAM entries that occurs when all rules are combined in a single memory structure.
Solution Approach 2:
The patent extracts the ACL filtering function from the NAT translation function by separating their rule storage into distinct TCAMs. This extraction allows the system to perform filtering and translation as independent operations, each with its own optimized rule set, thereby reducing overall TCAM resource consumption while maintaining full functionality.
2Device complexity
If a single TCAM stores both NAT and ACL rules, then the system structure remains simple, but scalability deteriorates as the number of rules increases
Solution Approach 1:
By segmenting the rule storage into two separate TCAMs, the patent enables the system to scale more effectively. Each TCAM can be independently sized and optimized for its specific rule type, allowing the system to accommodate larger numbers of NAT mappings and ACL filters without the quadratic resource consumption that would occur in a single unified TCAM structure.
3Ease of operation
If ACL filters and NAT mappings are combined in one TCAM, then rule management is straightforward, but the number of TCAM entries grows quadratically
Solution Approach 1:
The patent segments the rule management system into two independent management domains: one for ACL filters and one for NAT mappings. This segmentation reduces the total number of TCAM entries required because each TCAM only needs to store its specific rule type without requiring composite entries that combine both filter and translation rules, thereby eliminating the quadratic growth pattern.
Solution Approach 2:
The patent extracts the management complexity of combining different rule types by separating them into distinct TCAMs. This extraction allows each TCAM to be managed independently with optimized data structures for its specific rule type, reducing the overall number of entries needed while maintaining straightforward management practices for each rule category.
Data Source
AI summary
A system administrator can specify NAT mappings to perform NAT translations in a switch. The administrator can specify an ACL to filter packets to be translated. Filter rules generated from the ACL are stored in a first memory store in a switch and NAT rules generated from the NAT mappings are stored in a second memory store separate from the first memory store. When a packet matches one of the filter rules a tag that identifies the ACL is associated with the packet. When the tagged packet matches one of the NAT rules, the packet is translated according to the matched NAT rule.