Exact-Match Lookup Engine for Hierarchical Packet Forwarding
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Solution Overview
Problem
Current network protocols, such as IP and Ethernet, rely on location-based addressing schemes that are inadequate for handling variable-length identifiers, limiting their ability to efficiently process packets with hierarchically structured variable-length identifiers (HSVLIs) and perform longest-prefix-match lookups.
Innovation Solution
Adapting an exact-match lookup engine to convert HSVLIs into fixed-length addresses by generating prefixes and using exact-match lookups to perform effective longest-prefix-match lookups, facilitating the forwarding of packets with HSVLIs in existing network equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an exact-match lookup engine is used for fixed-length addresses, then lookup speed is improved, but it cannot handle variable-length identifiers like HSVLIs
Solution Approach 1:
The HSVLI is segmented into multiple fixed-length address components through prefix decomposition. Each prefix of the HSVLI is converted into a separate fixed-length address, allowing the variable-length identifier to be processed as multiple discrete units by the exact-match lookup engine.
Solution Approach 2:
A conversion mechanism acts as an intermediary between the HSVLI and the exact-match lookup engine. This intermediary converts the variable-length HSVLI into multiple fixed-length addresses that the lookup engine can process, bridging the gap between the two different data formats.
2Adaptability or versatility
If a longest-prefix-match lookup engine is used for variable-length identifiers, then adaptability to HSVLIs is improved, but device complexity increases compared to exact-match engines
Solution Approach 1:
Instead of modifying the simple exact-match lookup engine, the invention creates multiple copies of the HSVLI prefix as fixed-length addresses. Each prefix becomes a separate lookup key, allowing the simple exact-match engine to handle variable-length identifiers through multiple simple lookups rather than one complex lookup.
Solution Approach 2:
The system performs multiple exact-match lookups (excessive action) instead of a single longest-prefix-match lookup. By performing several simpler lookups on different prefix segments, the system achieves variable-length identifier handling without requiring a complex longest-prefix-match engine.
3Ease of manufacture
If location-based addressing schemes are used, then compatibility with existing protocols is improved, but network flexibility for content-centric routing deteriorates
Solution Approach 1:
The exact-match lookup engine, originally designed for simple fixed-length address matching, is made multi-functional by enabling it to handle HSVLIs through prefix conversion. This allows existing network equipment to perform both traditional location-based routing and content-centric routing with variable-length identifiers.
Data Source
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AI summary
One embodiment provides a system for forwarding packets with hierarchically structured variable-length identifiers (HSVLIs), wherein the computer includes a processor. During operation, the system converts an HSVLI into a number of fixed-length addresses, wherein the HSVLI indicates a piece of content and is hierarchically structured, and comprises contiguous components ordered from a most general level to a most specific level. In addition, the length of a respective HSVLI is not fixed. The system further performs an effective longest-prefix-match lookup by performing multiple exact-match lookups based at least on the fixed-length addresses.