Fast Packet Classification Using Bit Compression with Fast Boolean Expansion

1. Fast Packet Classification Using Bit Compression with Fast Boolean Expansion Author: Chien Chen, Chia-Jen Hsu and Chi-Chia Huang Publisher: Journal of Information Science and Engineering, 2007 Presenter: Chun-Yi Li Date: 2009/03/11

2. Outline • Related Work • Bitmap intersection • Aggregated Bit Vector (ABV) • Bit Compression Algorithm • Fast Boolean Expasion • Performance

3. Bitmap intersection Related Work • Each interval associated with an N-bits bit vector. R5 R6 R3 R4 R2 R1

4. Aggregated Bit Vector (ABV) Related Work Field1 0 1 00001110000 00000001100 010 011 0 0 1 00010001110 00100001101 11001110000 111 111 110 Field2 0 1 00000010110 011 1 0 0 1 Aggregate size = 4 00100100000 10000010110 00011000001 01000011110 111 111 110 111

5. Aggregated Bit Vector (ABV) Related Work • Aggregation tries to decrease thememory access time by adding ABV. • Generates false matching. - Rule rearrangement. • Faster than bitmap intersection, but use more space.

6. Outline Related Work Bitmap intersection Aggregated Bit Vector (ABV) Bit Compression Algorithm Fast Boolean Expasion Performance

7. Bit Compression Algorithm • Memory storage - θ(dN㏒N) • Require additional time for decompression

8. Bit CompressionAlgorithm Construct Don’t Care Vectors (DCV) Removing the redundant “1” bits Don’t Care Vectors (DCV)

9. Bit CompressionAlgorithm Removing redundant ‘0’ bits

10. Bit Compression Algorithm Construct Compressed Bit Vector(CBV) Append “index table lookup address” (ITLA) For convience of memory access, fill up ‘0’ to the end of the CBVs and index table.

11. Bit CompressionAlgorithm Construct index table Filled up with ‘0’

12. Bit Compression Algorithm Search (DCV)

13. Maxmum Overlap Analysis Bit Compression Algorithm β – denote the probability that PA is a prefix of PB. (PA and PBare randomly selected from the rule table)

14. Region Segmentation The region segmentation algorithm constructs an undirected graphfirst. Each vertex vi corresponds to a rule Ri, and an edge is constructed between vi and vj if rules i and j are dependent.

15. Region Segmentation • Find connected component. • Remove maximum degree vectex if set smaller than maximum overlap. Maximum overlap = 5 STEP3: C11 {1, 3, 4} C121 {1, 2, 5, 6, 8} C122 {1, 2, 6, 7} C2 {9, 10} STEP1: C1 {1, 2, 3, 4, 5, 6, 7, 8} C2 {9, 10} STEP2: C11 {1, 3, 4} C12 {1, 2, 5, 6, 7, 8} C2 {9, 10}

16. Merge Rule Set Two rule sets can be merged together if the rule numbers of the merged rule sets are smaller than or equal to the maximum overlap. CR1 {1, 3, 4} CR2 {1, 2, 5, 6, 8} CR3 {1, 2, 6, 7} CR4 {9, 10} CR1 {1, 3, 4. 9, 10} CR2 {1, 2, 5, 6, 8} CR3 {1, 2, 6, 7} Merge

17. Merge Rule Set

18. Merge Rule Set

19. Outline Related Work Bitmap intersection Aggregated Bit Vector (ABV) Bit Compression Algorithm Fast Boolean Expasion Performance

20. Fast Boolean Expasion(FBE) • Original boolean expression: (CBVS+DCVS)*(CBVD+DCVD) • Modify boolean expression: (CBVS*CBVD)+(CBVS*DCVD)+ (DCVS*CBVD)+(DCVS*DCVD) Takes few memory accesses since CBVSand CBVDare compressed bit vector. Default rule Only extract the essential bits from DCV that are corresponding to the set bits of CBV

21. Outline Related Work Bitmap intersection Aggregated Bit Vector (ABV) Bit Compression Algorithm Fast Boolean Expasion Performance

22. Performance

23. Performance

24. Performance Transmission rate Without wildcard rule (K)

25. Performance Transmission rate Contain 20% wildcard rule (K)

26. Performance Transmission rate Contain 50% wildcard rule (K)