ERFC: An Enhanced Recursive Flow Classification Algorithm

Abstract

Packet classification on multi-fields is a fundamental mechanism in network equipments, and various classification solutions have been proposed. Because of inherent difficulties, many of these solutions scale poorly in either time or space as rule sets grow in size. Recursive Flow Classification (RFC) is an algorithm with a very high classifying speed. However, its preprocessing complexity and memory requirement are rather high. In this paper, we propose an enhanced RFC (ERFC) algorithm, in which a hash-based aggregated bit vector scheme is exploited to speed up its preprocessing procedure. A compressed and cacheable data structure is also introduced to decrease total memory requirement and improve its searching performance. Evaluation results show that ERFC provides a great improvement over RFC in both space requirement and preprocessing time. The search time complexity of ERFC is equivalent to that of RFC in the worst case; and its average classifying speed is improved by about 100%.

Optimization of Lookup Schemes for Flow-Based Packet Classification on FPGAs

“…Precomputation for ruleset population in the original RFC scheme [13] could take hours to execute for complex rule overlappings such as those of ruleset ipc1 [46]. Computation complexity was further optimized in [14,47], achieving improvements over the original scheme. During ruleset population, URs are computed by considering a fixed ruleset size.…”

“…er mem and bnd mem scale as (2 ⋅ log 2 (2|UV|)) and ( ), respectively, while bv mem scales as ( ); thus gain can be obtained in memory consumption. Our proposal can be combined with those of [47] to get an optimized IND-based lookup. Contributions of [47] are, namely, the following: (1) it reduces the number of AND operations for checking BV…”

“…Our proposal can be combined with those of [47] to get an optimized IND-based lookup. Contributions of [47] are, namely, the following: (1) it reduces the number of AND operations for checking BV…”

An optimized RFC algorithm with incremental update

“…In paper [8], authors proposed an enhanced RFC (ERFC) algorithm, in which a hash-based ABY scheme is used to speed up its preprocessing procedure. The authors claim that the search time complexity of ERFC is equivalent to that of RFC in the worst case; and its average classifYing speed is improved by about 100%.…”

“…We also use the idea from paper [8] which uses ABV algorithm for CBM intersection. We can consider RFC phase 1 onwards preprocessing phases as ABV method's search procedure.…”